On farms across America, it is common practice to hand-deliver colostrum to newborn dairy calves. Although it varies amongst each operation if they choose to feed maternal colostrum or a colostrum product, each calf is getting a measured feeding of colostrum.

 

In contrast, when beef calves are born, they are not commonly fed by hand as cattlemen typically depend on the calf to suckle enough colostrum from the dam. Data shows, only 1 in 5 dairy calves on average have failure passive transfer (FPT), whereas 1 in 3 beef calves have FPT. This means we should not assume that every beef calf is receiving sufficient colostrum from the dam within the first few hours of life.

To prevent this, let’s discuss when beef calves should receive a colostrum supplement or replacer to best ensure calves are getting the immunity and energy they need.

 

RISKS OF DYSTOCIA

When a calf is born and consumes colostrum within the first two hours of life, it can typically absorb about 30- 40% of the immunoglobulins (IgG) in the colostrum. This efficacy of absorption can quickly be disrupted by stressful calving events like dystocia. Hard-pulled calves or calves with abnormally long presentation time can show reduced absorption rates of 20-26%. This means those stressed calves should not rely entirely on maternal colostrum from the dam and need to be fed higher IgG levels to meet their needs for successful passive transfer of immunity. In addition, these calves are usually weaker and slower to get up to nurse, and delayed colostrum consumption can also decrease their absorption rate.

To ensure these stressed calves receive the colostrum they need, we recommend tube-feeding a minimum of 200g IgG replacement within the first two hours of life. If they do not stand to suckle from the dam within six hours of that initial feeding, we recommend following up with an additional 100g IgG supplemental feeding.

 

NIGHT CALVING

Although we cannot avoid calves being born in the middle of the night, we can be prepared to properly manage those calves without adding stress to the cattleman. Night-born calves are typically not monitored as diligently as those born throughout the day. As soon as a calf is born, its absorption of IgGs is at its peak, and after about four hours it starts to rapidly decline. So, we need to be sure nightborn calves do not have delayed colostrum consumption resulting in reduced IgG absorption putting them at risk of failure passive transfer.

In order to prevent this, night-born calves should be quickly fed a full colostrum replacer (200g IgG) so that the person on watch does not have to sit to monitor how rapidly the calf gets up to nurse. If the calf was born several hours before it was noticed, it should also be immediately fed a colostrum replacer since it should not be assumed that calf has already nursed to receive sufficient colostrum from the dam.

 

COLD STRESS

Calving season can take place during some of the harshest weather conditions. Newborn calves born in cold weather can be at risk for hypothermia. USDA estimates approximately 95,000 calves die each year of hypothermia. The best method to prevent hypothermic calves is to provide calves a potent energy source to thermoregulate. Colostral fat, found in only whole bovine colostrum replacers and supplements, is the most digestible and efficient energy source to allow calves to metabolize the brown fat they are born with. That allows calves the ability to regulate their body temperature and enough energy to shiver to stay warm.

You can start by delivering the calf a colostrum supplement that is high in colostral fat right after birth. If the calf does not stand to nurse off the dam within six hours of providing the supplement, you should follow up with an additional supplement to ensure the calf receives a total of 200g IgG within the first eight hours of life.

 

FIRST-CALF HEIFERS

First-calf heifers can have a few issues during calving season. They can be vulnerable to dystocia if they were not bred calving-ease, and they also produce less colostrum volume compared to cows. On average, heifers produce only 3-4 liters in the first milking whereas cows produce 5-7 liters. Low colostrum volume in first-calf heifers can put their newborn calves at risk of not consuming enough colostrum within the first few hours to achieve successful passive transfer.

To avoid this risk, we recommend supplementing all calves born to first-calf heifers with a colostrum product made with whole colostrum. This supplement should be given in addition to calves suckling off the dam. Calves should receive 10% of their birth weight in colostrum volume (for instance a 40Kg calf should receive 4 liters of colostrum). By consuming a supplement plus nursing off the dam, these calves should be reaching that amount.

Calving season can be stressful on both the calves and the ranchers. Although we cannot predict when these challenges will come during calving season, we can be prepared for them by having high-quality whole bovine colostrum products readily available on-farm to use when the need arises.

 

The summer heat can have a large impact on a dairy herd, but the impact on calves in particular is often overlooked. Heat stress can have long term effects on the future productivity of growing heifers. As calves feel the summer heat, help keep them comfortable by following a few simple cooling practices.

A calf’s body temperature will rise and fall with the surrounding air temperature. When night temperatures remain above 78°F, calves are unable to return to their normal body temperature. Installing fans in a calf nursery has been shown to slow breathing rates and increase growth by 15% (Bateman, 2012). Installing shade structures over calf hutches can also greatly reduce the air temperature inside by up to 5.4°F, helping reduce the effort of keeping cool.

Similar to lactating cows, calves also consume less feed during heat waves. Growth rates would be expected to drop accordingly, and as shown in Figure 1, growth rate decreases by a greater amount than feed intake as temperature increases. Calves expend energy to keep cool, primarily by panting. This means energy for maintenance is increased leaving less energy available for growth.

Research has found immunoglobulin concentrations in the blood of calves born during heat stress are reduced due to failure of passive transfer (FPT) (Hill et al., 2012). This occurs not only because cows produce lower levels of immunoglobulin in their colostrum when heat stressed, but a calf’s ability to absorb these immune proteins is also diminished.

In a study comparing calves raised in three environments, cold (23°F), thermo neutral (74°F), and hot (95°F), the calves exposed to the hot conditions showed immunoglobulin levels 27% lower than the calves in the thermo neutral environment which resulted in higher mortality. Hutches are poor environments for calves in areas of extreme heat. Particularly when positioned in the sun, hutches trap heat and reduce air flow to cool the calf inside. In Figure 2, cortisol levels are higher when the calf is housed in a hotter environment such as a calf hutch. Cortisol is a hormone produced in higher levels during stress. Looking back at the graph, immunoglobulin concentration in the blood of calves decreases as cortisol levels rise demonstrating calves are less able to absorb colostral immunoglobulins when exposed to stress from hot environments.

Lower immunoglobulin levels can also lead to increased cost of treatment, lower milk production, and reduced growth rates, subsequently delaying pregnancy. To avoid these outcomes, it can be beneficial to provide calves born during times of heat stress with a colostrum supplement or replacer to ensure high levels of immunoglobulin available for uptake by the calf.

Ultimately, taking steps to reduce heat stress in calves will result in increased profits long term. Calves can drink anywhere from 11 to 22 liters of water per day to replace fluids lost trying to stay cool (Bungert, 1998). For this reason it is very important to provide clean free choice water to calves at all times. A method of reducing the air temperature inside calf hutches is building shade structures over the hutches. As well as reducing air temperature, air movement is also crucial as is allowing evaporative cooling of the calf so proper ventilation should be in place. All these methods used in conjunction with providing a colostrum supplement or replacer at birth will set your calves well on their way to leading long, healthy productive lives.

 

 

REFERENCES

 

G. Bateman, M. Hill. 2012. “How heat stress impacts the growth of calves.” Dairy Basics; April

K. Bungert. 1998. “Calves feel the heat too.” Dairy Herd Management; 35, 5: 15.

T.M. Hill, H.G. Bateman II, J.M. Aldrich, R.L. Schlotterbeck. 2012. “Case Study: Effect of feeding rate and weaning age of dairy calves fed a conventional milk replacer during warm summer months.” Professional Animal Scientist 28:125-130

J.N. Spain, D.E. Spiers. 1996. “Effects of Supplemental Shade on Thermoregulatory Response of Calves to Heat Challenge in a Hutch Environment.” Journal of Dairy Science Vol. 79, No. 4.

Stott et al. 1975. J Dairy Sci. 59:1306 – 1311

With the ever changing global limitations on antibiotic use and the increased need for more natural therapies, colostrum has shown to be an effective alternative to minimize the days to resolution of diarrhea and improve average daily gain in preweaned calves.

Diarrhea in preweaning calves is a multifactorial disease that is contracted due to a combination of environmental, management, and pathogenic factors. This is one of the reasons why it is the primary cause of morbidity and mortality as well as one of the leading causes of antimicrobial therapy in dairy calves1. Alone, diarrhea can have short-term and long-term consequences related to health, welfare, and productivity. Additionally, the use of antimicrobials can negatively affect the calf’s gut microbial communities, leading to diminished immune function2. This combination, paired with concerns related to antimicrobial resistance, justifies the need for alternate diarrhea therapies for calves.

Bovine colostrum is specifically tailored to meet a calf’s need for immune function, growth, and development. For centuries, bovine colostrum has been used as a treatment and preventative in humans and other species, but its benefits as a therapy for calves have yet to be explored. Its ample supply of antibodies, nutrients, hormones, growth factors, vitamins, and minerals as well as antimicrobial and anti-inflammatory properties provide several therapeutic benefits such as cell growth and reparation. The benefits of colostrum create an enticing argument that it may have the potential to act as a therapy for diarrhea in preweaning calves.

A study was completed at the University of Guelph to explore the impact of colostrum as a therapy for diarrhea in preweaned calves. It was completed at a commercial calf-raising facility in Southwestern Ontario during the summer of 2021. Over the 6-week period, 108 calves were enrolled once they had visible diarrhea. Once enrolled, each calf was randomly allocated to receive one of three treatments:

1) control (CON); eight feedings over 4 days of 2.5 L of milk replacer at a concentration of 130 g/L,

2) short-term colostrum supplementation (STC); four feedings over 2 days of 2.5 L of a mixture of milk replacer and colostrum replacer, each with a concentration of 65 g/L, followed by four feedings over 2 days of 2.5 L of milk replacer at a concentration of 130 g/L, or

3) long term colostrum supplementation (LTC) eight feedings over 4 days of 2.5 L of a mixture of milk replacer and colostrum replacer, each with a concentration of 65 g/L.

Several variables were recorded during this study including serum immunoglobulin G concentration, severity of diarrhea at enrollment, fecal and respiratory scores, and weight gain to evaluate their contributing effects on diarrhea resolution.

 

Calves allocated to the LTC treatment group showed several significant and positive results. When compared to the CON group, calves in the LTC group had a reduced duration and severity of diarrhea. Figure 1 illustrates the mean time to resolution of diarrhea across treatment groups. Several variables influenced diarrhea resolution; an increased body weight at the onset of diarrhea and the number of days to enrollment since facility arrival reduced the time to resolution of diarrhea. However, calves infected with two or more different pathogens and calves enrolled with a more severe fecal score on a scale of 0-3, had an increased time to resolution.

Calves in the LTC group also showed improved growth rates compared to CON calves, gaining 98 g/day more. Figure 2 illustrates the growth curves of each treatment with calves in the LTC group being significantly larger on days 42 and 56 following enrollment.

Results from this study indicate that feeding a low dose of colostrum over an extended period can effectively minimize the days to resolution of diarrhea and improve average daily gain in preweaned calves. Future research should explore the most optimal dose and duration of the treatment that can be effectively and practically used by producers.

 

 

Havie Carter, B.Sc.(Agr.)

M.S.c Candidate, Department of
Population Medicine, University of Guelph
[email protected]

 

 

When considering treatment of scours, there are several options for prevention, supportive therapy and treatment that do not involve reaching for the bottle of antibiotics. By identifying the weaknesses in the chain of disease, we can avoid calfhood scours altogether

Prevention is the single most important step in managing calf scours. Whether a calf stays healthy or gets scour is determined by the balance between the resistance of the calf to infection and the level of infection to which it is exposed.

• Provide adequate colostrum in the first few hours after birth.

• 10% of calf’s body weight of colostrum >24 Brix in the first 2 hrs of life.

• 5% of calf’s body weight of colostrum >24 Brix at 6-8 hrs of life.

• In order to achieve excellent passive transfer calves must receive 300 grams of IgG in the first 8 hrs of life.

• Provide proper housing or shelter from the weather to reduce stress.

• Carefully plan calf housing to avoid overcrowding.

• Avoid mixing different ages (i.e. new born calves with calves older than 3-4 days) as younger calves will be more susceptible.

• Minimize stresses associated with routine management practices e.g. disbudding, castration, vaccination.

• Maintain strict hygiene by cleaning and sterilizing feeding utensils and facilities.

• Prevent the build-up of fecal contamination around feed and water troughs. Keep fening areas and water buckets/ troughs off the ground.

• Individual or group calf pens/hutches must be cleaned out and disinfected between animals.

• Clean out bedding regularly or generously top dress bedding. Check bedding by kneeling in the pen; your knees should not get wet if the bedding is dry enough.

• Develop a routine milk feeding program with as few people involved as possible.

• Respond quickly to symptoms of scour; isolate sick calves and address the cause.

• Implement a sound scours vaccine program for dry cows. The vaccinated cow produces more antibodies to rotavirus, coronavirus, cryptosporidium, and E.coli and delivers them in her colostrum. Purchase calves from cows that have been vaccinated with a scours vaccine before calving.

Generalized Treatment of Scours

Although specific treatments are available for scours depending on the causal pathogen, the following steps should be taken in all cases to ensure calf recovery:

1. Isolation

• Scouring calves should be isolated in a clean, dry, and warm pen.

2. Rehydration therapy

• Once scouring, a calf becomes rapidly dehydrated, acidotic, and low in essential electrolytes such as sodium (Na), Potassium (K), and Chloride (Cl). They can lose 5% to 10% of their body weight daily in fluids. Treatment involves rehydration, correction of acidosis, and replacement of electrolytes. Some electrolyte products on the market, while assisting with rehydration and replacement of electrolytes, often fail to effectively correct acidosis. Correcting acidosis is essential for calf recovery.

• Calves must receive sufficient liquid and electrolytes to replace those lost in the feces.

• Frequent, small, feeds of electrolytes or milk are better than fewer larger ones.

• Healthy calves need up to four liters of fluid a day, and scouring calves need an additional four liters to replace lost fluids.

• Electrolyte scours treatments must have a Strong Ion Difference (SID) of 60mmol.

• The amount of electrolytes needed depends on the extent of the calf’s symptoms. Overfeeding electrolytes causes little detriment to calves. However, underfeeding electrolytes can prolong scours and not correct the dehydration and loss of electrolytes.

3. Milk feeding

• Continuing to feed milk or good quality milk replacer will not prolong or worsen the scour and can help to heal the intestine.

• Continue to offer scouring calves normal amounts of milk or milk replacer for as long as they want to drink it.

• If reintroducing milk, it should be offered full strength. Milk should never be diluted with electrolyte solutions as this can lead to poor milk clotting.

• Electrolytes should be given at least 30 minutes before a milk feed.

• Milk or milk replacer should not be stomach tubed.

4. Colostrum

• Feeding colostrum during scours is an effective treatment for a variety of scours pathogens.

• Feeding colostrum as a treatment has demonstrated a significant reduction in the number of scouring days and severity. It has also proved to significantly increase average daily gain over calves that are treated with antibiotics.

• To use colostrum as a treatment:

• Feed 140-150 grams of colostrum mixed in 1 liter of water as a separate feeding.

• Feed colostrum 1x/day for 5 days, or until diarrhea is resolved

• Mixing 140-150 grams of colostrum and electrolytes in 2 liters has also been very effective at treatment and rehydration.

Note: It is important to remember that not all electrolytes are created equal and some electrolyte/colostrum combinations are not advised. Please consult wit your veterinarian to determine the best combination.

5. Antibiotics

• Antibiotics do not work against the parasites and viruses which are the most common causes of calf scour.

• Antibiotics should only be given:

1. After consulting with your veterinarian

2. By injection

3. Calf has a temperature above 102.5°F.

In summary, prevention is key to avoiding calfhood scours. If disease does occur, supportive therapy and alternative treatments such as feeding colostrum can help calves recover, and thrive again.

 

Dr. Travis White, DVM.

Director of Veterinary Technical Services, SCCL
[email protected]

REFERENCES

Feeding colostrum as a therapy for diarrhea in preweaned calves

1. Urie, N. J.; Lombard, J. E.; Shivley, C. B.; Kopral, C. A.; Adams, A. E.; Earleywine, T. J.; Olson, J. D.; Garry, F. B. Preweaned Heifer Management on US Dairy Operations: Part V. Factors Associated with Morbidity and Mortality in Preweaned Dairy Heifer Calves. J. Dairy Sci. 2018, 101 (10), 9229–9244. https://doi.org/10.3168/jds.2017-14019.

2. Oultram, J., E. Phipps, A.G.V. Teixeira, C. Foditsch, M.L. Bicalho, V.S. Machado, R.C. Bicalho, and G. Oikonomou. 2015. Effects of antibiotics (oxytetracycline, florfenicol or tulathromycin) on neonatal calves’ faecal microbial diversity. Vet. Rec. 117:598. doi:10.1136/vr.103320.

There’s no better time than summertime, but the stress from the heat can take it’s tole on pregnant cows, and their calves. The effects last long into the pre-weaning period, so care needs to be taken to avoid heat stress in the animals that are the future generation of the herd.

During the summer months, it is hot and humid and we notice that our lactating cows reduce their feed intake and in turn they do not produce as much milk as they did during the cooler season. Similarly, when cows are exposed to heat stress during late gestation, we see compromised mammary gland development before calving, followed by decreased milk production after calving. While the physiology of what is happening to our cows during heat stress is well understood, there is much less concrete evidence about how this can affect the unborn calf and colostrum quality.

The results of heat stress during the pre-partum period on calf growth are well-agreed upon among researchers and similar results are seen across studies when we have calves born to cows that are either exposed to a heat-stress environment or a cooled environment. For starters, calves born to heat-stressed cows weigh less at birth compared to calves born to cooled cows. Research conducted in the 1970s has shown that this occurs due to decreased blood flow to the uterus, as well as decreased placental weight, which results in fewer nutrients reaching the fetus and thus a lighter calf at birth. Moreover, heat-stress often decreases the length of gestation, which can also affect calf birth weight. These weight differences may carry over into the pre-weaning and weaning period. For instance, a study conducted in 2017 demonstrated that cooled calves gained 0.2 kg more per day and weighed 4 kg more at weaning compared to heat-stressed calves.

In addition to affecting growth, calves born to heat-stressed cows are also less efficient at absorbing IgG compared to their cooled counterparts. Multiple studies over the last decade have demonstrated that compared to cooled calves, heat-stressed calves have lower blood IgG concentrations and lower apparent efficiency of absorption (AEA) of IgG. The apparent efficiency of absorption of IgG basically tells us how much IgG the calf is absorbing from the colostrum on a percentage basis. For example, a study conducted at the University of Florida reported that heat-stressed calves were only able to absorb 12% of the available IgG from colostrum, while cooled calves were able to absorb 20%. In this study, as well as many others, calves are fed colostrum from their own heat-stressed dams.

This led researchers to form two questions:

1. Are the differences in IgG absorption due to heat-stressed calves being fed poor quality colostrum from heat-stressed cows?

2. Are heat-stressed calves less efficient at absorbing IgG because of an effect of the heat-stress during gestation on the calf itself?

Regarding the first theory, reports on whether or not heat-stressed cows have decreased colostrum quality are conflicting. Many studies have found that heat-stressed cows have lower colostrum quality (amount of IgG/L) and quantity (total amount of colostrum produced) compared to cooled cows. In support of this research, testing of more than 100,000 colostrum samples per year over the last 20 years from our lab (SCCL, Saskatoon, Canada) has demonstrated that IgG in colostrum can decline by up to 20% in the summer compared to other seasons. Yet, some studies are still reporting that there is no difference between the colostrum of heat-stressed and cooled cows. Many of these studies often pool colostrum from heat-stressed cows, test colostrum from only a small group of animals, or do not record the colostrum yield; all of which may affect the concentrations reported. However, as there are many factors that can influence colostrum quality aside from calving season, it is always a good idea to test the quality of your colostrum before feeding it to your calves to ensure passive immunity regardless of the time of year.

While the research on colostrum quality in heat-stressed cows is conflicting, a study in 2014 sought out to determine whether the decreased passive immunity in heat-stressed calves was due to a colostrum effect or due to the second theory mentioned above: a calf effect. This study demonstrated that even when both groups of calves are fed the same colostrum from cows kept in a thermoneutral environment, heat-stressed calves still have a lower blood concentration of IgG at 1 day of life compared to cooled calves. Moreover, when calves born to thermoneutral dams were fed colostrum either from heat-stressed or cooled cows, no differences in blood IgG concentrations were observed. This shows us that regardless of the colostrum source, heat stress during the last weeks of pregnancy somehow negatively affects the calf’s ability to absorb IgG when it is born.

So, why are heat-stressed calves less efficient at absorbing IgG? As mentioned previously, calves born to heat-stressed cows are lighter at birth, which may lead to a lower small intestinal surface area to absorb IgG. Basically, no matter how much IgG is fed, smaller calves do not have as much surface area on their small intestine to absorb it into the blood. Researchers have also hypothesized that heat stress during late pregnancy may impair the development of the small intestine; either resulting in less surface area for the absorption of IgG or a decreased number of intestinal cells available to absorb the IgG.

In summary, calves born to heat-stressed cows have a lower birth weight, reduced growth during the pre-weaning period, and a decreased ability to absorb IgG from colostrum compared to calves born to cooled cows. Although research regarding the quality of colostrum from heat-stressed cows varies, it is important that we feed calves born during the summer season the best quality colostrum possible in order to increase their chances at being as healthy and productive as their cold season counterparts.

 

Mike Nagorske, DVM.

Director of Research, SCCL
[email protected]

Calfhood Diarrhea is the most common health problem affecting young cattle and milk-fed animals. Calves are particularly susceptible during their second week of life. Up to 40% of calf deaths in the first six weeks of life are scour related. It is important that we know how to identify them before we begin to apply treatment options.

1. Causes of calf scours:

Scours can be classified into two types: nutritional and infectious. Nutritional scours is usually caused by stress due to a breakdown in management routine. Nutritional scour often progresses to become an infectious scour, which is caused by a high population of pathogens. Several infectious agents can cause scour in calves and often more than one of them is involved:

2. Symptoms of scours:

Calf scours is easily recognized, with calf feces increasing in frequency and quantity, and having a higher-than-normal water content. Whatever the cause, farmers will see some or all of the following:

• Bright yellow or white feces.

• Depressed calves who are reluctant to feed.

• Calves with sunken eyes and/or a temperature.

• Skin remaining peaked or tented when lifted, indicating dehydration.

• Weight loss and weakness.

• In severe cases, calves will collapse, become comatose and die.

With careful observation, it is possible for calf raisers to anticipate the onset of scour the day before it occurs by looking out for the following signs:

• Dry muzzle, thick mucus appearing from the nostrils.

• Very firm feces.

• Refusal of milk.

• A tendency to lie down.

• A high body temperature (over 102.5°F).

Estimation of hydration status in calves with diarrhea

 

 

Dr. Travis White, DVM.

Director of Veterinary Technical Services, SCCL
[email protected]

Many farms wish to use the colostrum they already have available, but often it falls short of perfect. A new way of feeding colostrum allows producers to boost the quality their maternal colostrum before feeding it to the calf.

It is now widely known colostrum is essential for calf survival, performance and has impacts on lifelong productivity.

Colostrum management typically involves managing colostrum and implementation protocols with emphasis on four main points:

1. Timing of administration (within the 1st two hours and a second feeding within 12 hours)

2. Colostrum Quality (concentration of IgG antibodies greater than 50 g/L)

3. Colostrum cleanliness (low pathogen load or bacteria counts)

4. Colostrum quantity (typically 10% of the body weight in kg).

These management facets are all equally important. For example, a producer could do a good job managing three out of the four and yet still have poor calf health. If lets say the timing, colostrum cleanliness and colostrum quantity are all being managed well, but the colostrum lacks proper antibody levels, it results in more calves failing transfer of passive immunity (FTPI). When calves either do not get enough colostral antibodies or none, the risk for scours, respiratory disease and overall death loss increases by upwards of fourfold in the first 60 days of life. This happens because in a sense the dam of the calf is passing her immunity onto the calf via the colostrum, and this is also why we call the phenomenon passive transfer. For this article, lets focus on the colostrum quality or concentration of antibodies/ IgG. And while we will discuss the proper antibody levels, it is important to realize colostrum is much more than just antibodies. It is packed full of on the order of hundreds of bioactive factors, natural pre-biotics, nutrients and vitamins/trace minerals.

How do you determine the antibody or IgG concentration in colostrum?

While the gold standard way to measure colostral antibody/ IgG concentration is by a highly technical laboratory method called radial immunodiffusion, an indirect way to measure it on farm is with an optical or digital brix refractometer. Again, these devices are “indirect” measurements of true colostral IgG content and are indeed about 80% accurate. A brix level of 22% equates to approximately 50 g of IgG per L. Therein, if a person were to feed a 90lb/40kg calf 4L of 22% brix colostrum, it would provide a mass of 200 grams of IgG to the calf. This has served as a rule of thumb over the years for a Holstein calf which is to feed 10% of the body weight (.1 X 40 = 4L) at 22% brix (50 g IgG/L x 4 = 200 grams IgG). There are new recommendations; however, indicating calf morbidity and rate of failed transfer of passive immunity (FTPI) decrease by providing more colostral antibody/IgG. In fact, these new recommendations aim now to provide 300 grams of IgG in order to achieve excellent passive transfer. So what does this mean in terms of brix? Well, it means we need to raise standards on farm to select colostrum with brix levels above 24% brix.

Should we brix every batch of colostrum fed or every milking of colostrum from individual cows?

The answer is yes, we should. The reason being is colostrum is highly variable in terms of antibody concentration. In fact, there are genetic differences between cows, dry cow nutrition, seasonality, parity and timing of collection are just some of the factors, to name a few, which contribute to the variability. Research over the years has shown that upwards of 30% of colostrum has antibody below 50 g/L (and remember this is based on old standards where 22% brix = 50 g/l IgG) and a recent survey study conducted by the National Health Monitoring Study in 2014 showed approximately 23% of colostrum to have below 22% brix. This is something to consider when new standards indicate to feed colostrum with greater than 24% brix levels. Does this mean as well that colostrum is worthless below 22 % brix? How can we manage to use colostrum below 24 % brix? First and foremost, one rule of thumb which still stands true today is to discard any colostrum with brix levels below 15-16%. Brix levels at these levels typically indicates colostrum has less than 30 g of IgG per Liter and it does not provide enough immunity for calves.

So what if the colostrum brix test between 15-24% brix?

One solution is to use this colostrum for a second feeding between 6-12 hours birth; however, a new application called “enrichment” can be performed with efficacy.

There is a solution!…. Enrichment!:

Enrichment involves adding a precise amount of colostrum replacer powder directly to maternal colostrum. Therein if the brix level falls between 15-24%, enriching with colostrum replacer of a consistent IgG level can indeed turn poorer quality colostrum into excellent quality maternal colostrum.

A new research study conducted at the University of Guelph proved this to be an efficacious way to improve maternal colostrum. In the study, Researchers fed maternal colostrum at various brix levels with the lowest level being 15.8% brix (equated to 30 g of IgG per liter).

On calves fed maternal colostrum at 15.8% brix, 18.8% failed transfer of passive immunity.

They also fed colostrum which was enriched from 15.8% brix up to 26% brix and were able to achieve good levels of passive transfer while have 0% of calves failing transfer of passive immunity (compared to the 18.8% mentioned had they not enriched).

The Researchers also enriched from 20.3% brix to 31.3 % brix and they achieved on the average excellent passive transfer in the calves. In fact, the calves fed the 20.3% brix colostrum had only 50% of the calves achieving excellent passive transfer and 6.25% achieving fair passive transfer.

After enriching the 20.3% colostrum to 31.3% brix they were able to achieve higher passive transfer levels with 62.5% of calves achieving excellent passive transfer and 0% achieving fair passive transfer (vs only 50%).

Again, based on research indicating lower morbidity for calves achieving excellent passive transfer, the enrichment strategies proved to improve transfer of passive immunity and significantly decrease the percentage of calves failing transfer of passive immunity.

Enrichment is an excellent way to still use maternal colostrum that you have on hand from the dam and boost it’s quality with a colostrum product.

 

Mike Nagorske, DVM.

Director of Research, SCCL
[email protected]

 

Newborn calves are extremely susceptible to environmental conditions. Both heat and cold stress play a major factor in a calf ’s ability to survive the first days of life, and their comfort range is much more narrow than we would think. Mother nature can deliver the weather, but we can deliver colostrum that will give calves a fighting chance.

We know the significant impacts of failure of passive transfer from low IgG consumption after birth, but did you know colostral fat can also impact the overall health and performance of newborn calves? Neonatal animals in terms of both calves and small ruminants are sensitive to cold temperatures. Many may think of cold stress happening at temperatures below freezing; however, it does not take much in terms of cool ambient air to induce cold stress to a neonate. The thermoneutral zone is one way to describe this phenomenon. It is a range of temperatures where an animal will not require additional energy, metabolism or physiological defense mechanisms to maintain its body temperature. The ambient temperature below what is considered the lower critical temperature (LCT) would thereby induce an animal to increase metabolic heat production to defend its body temperature. When the temperature goes above the upper critical temperature (UCT), the animal must also expend energy to maintain body temperature and prevent over-heating. And the physiologic mechanisms to do so require energy.

Thermalneutral Zone

Despite variances in environmental conditions, the thermoneutral zone of most calves is between 13.4°C/56°F and 25°C/77°F.

This means, if the temperature goes below 13.4°C/56°F, it induces cold stress and requires the calf to defend its body temp in ways we will discuss. The same goes for the upper range inducing heat stress above 25°C/77°F.

Let’s say for example, it is a cold winter night and a cow calves. The temperature is 10 degrees C/50 degrees F.

What then is required for this animal to defend its body temperature given it is literally coming into this world below its thermal-neutral zone?

In other words, how is this neonate going to produce enough heat to maintain its bodily functions? The answer lies in two important physiologic responses.
One is through shivering thermogenesis, and the other is through non-shivering thermogenesis involving brown adipose tissue metabolism (also called Brown fat). Studies proving this phenomenon stem all the way back to the 80’s where Vermorel et al (1983) placed newborn calves in a 37 degree C water bath and found shivering began at 32 degrees C. Shivering worsened as they cooled the water; in fact, heat production increased by as much as 100%. So, with the calf just born, it is likely shivering is going to take place visually.
Research in neonatal lambs has shown that approximately 60% of the thermogenic response is due to shivering and the other 40% due to brown fat metabolism (Carstens 1994). This fresh calf just born will therein shiver most certainly and then it will also tap into the most potent heat producing organ in its body: brown fat! Interestingly, the brown fat this calf likely has will only constitute 1-2% of its body weight at birth and yet still contribute 40% of its thermogenic capability. (Fun fact: Believe it or not, brown fat, even though 1-2% of the body weight is an actual organ).

What can we do to trigger heat production?

So with this calf now having two mechanisms to defend its body temperature through shivering or brown fat metabolism, it should be okay right? We can just in sense walk away and go to bed? Well, one might want to make sure the calf at least stands up. A study conducted by Vermorel et al, found heat production in newborn calves to increase by 100% when calves stood for 10 minutes and by another 40% when they stood for 30 or more minutes. Activity as simple as standing increases muscle movement and indeed triggers heat production.

Is there anything we can give the calf to warm them up?

There is one more thing we need to consider which may be most important. Colostrum! While there are antibodies and hundreds of bioactive factors in colostrum to provide immunity and tissue growth, colostral fat is an important player in cold stress. Colostral fat has a unique fatty acid profile and serves as a substrate for the brown fat cells. In a sense, it provides the proverbial jet fuel for the potent heat producing brown fat. The brown fat cells take in the fatty acids from colostrum and then it sparks combustion to where the cell literally produces heat. Interestingly, there are other bioactive factors in colostrum which recruit more brown fat cells to mature into functional heat producing machines. These include growth factors in the colostrum which have been documented in research to proliferate more brown fat cells, namely, fibroblast growth factor (FGF), insulin-like growth factor (IGF), Epidermal growth factor (EGF) and platelet derived growth factor (PDGF).

Therefore, whether a calf is beef or dairy and the temperature is below the lower critical temperature (ie.. 13.4 degrees C/56 degrees F), it is vitally important this calf receives colostrum. This will do three things:

1. It will supply an abundance of energy to get the calf to stand up (and remember heat production increases with activity)

2. It will provide the unique colostral fat to jump start the brown fat cells to produce heat

3. The plethora of growth factors in the colostrum will recruit more brown fat cells (in a sense make more heat machines).

Can a colostrum replacer can be used as a tool in a beef or dairy calf to play a role in thermogenesis?

Are colostrum replacers the same as the maternal colostrum produced by the beef or dairy cow? This is where things can get dicey. Unfortunately, not all colostrum replacers are created equal. Many colostrum replacers are made from blood serum, whey, whey protein concentrate, and do not have only colostral fat as the main energy source. Fat sources can include but are not limited to animal fat, vegetable oil, coconut oil, dairy and palm fat to name a few. These fats do not have the same or unique fatty acid profile as colostral fat. Fat is therefore also not created equal, and this has shown to have ramifications in terms of brown fat stimulation. Researchers have shown for example polyunsaturated fats (i.e… omega 3 and 6 fatty acids… fish oil) vs saturated fats (tallow, animal fat, butter, etc.) have shown to have both recruiting and stimulation effects on brown fat. (in terms of contributing key cell components (UCP1 protein content) which spark heat production in brown fat cells). In fact, research by Wilms et al (2022) shows colostral fat to be higher in polyunsaturated fatty acids compared to whole milk. The polyunsaturated fat called omega-3 fatty acid was 45% higher in colostrum compared to whole milk (fun fact: Eicosapentaenoic acid (EPA), a type of omega three fatty acid, was 73% higher in colostrum vs whole milk and it produces signaling molecules to reduce inflammation in the body). It is likely there is a physiological reason for this, and it raises doubt amongst many of the fat sources used in synthetically derived colostrum replacers on the market.

What should we look for in a colostrum replacer?

If a colostrum replacer is used, be sure to check it is made from whole bovine colostrum and colostral fat… not a different fat source!

To further prove the point of the importance of colostral fat in colostrum replacers, research was performed looking at colostrum replacer with low fat levels. It is important if a colostrum replacer is utilized it not only contains colostral fat (derived from pure bovine colostrum) but also enough fat.

The study compared colostrum replacer with 22% fat vs defatted colostrum at 5.7 % fat. Both replacers had the same amount of IgG/antibody with the only difference being the fat content. The study was designed such to not stimulate shivering and attempt to stimulate only brown fat metabolism (Min temp 13.4 Degrees C and average temp of 21.4 degrees C).

The results were astounding! Calves fed the defatted colostrum replacer had a 50% increase in respiratory disease in the first 90 days of life and a 6% increase in mortality. They also had lower rectal temperatures and spent less time standing and more time in a lying position. Interestingly, the calves fed defatted colostrum had lower weight gain in the first 4 months of life. The calves fed the full fat colostrum gained 6.6 kg/14.6 lbs more at 90 days of age and 10 kg/22 lbs more at 127 days of age. This equates to a difference in average daily gain of 0.07 kg/d (.154 lbs/d) in the first 90 days and 0.1 kg/d (.22 lbs/d) at 127 days of age. The impact on weight gain was immense and economically it means one can spend money on colostrum replacer with full fat and whole colostral fat.

In a conservative approach, lets say it costs $1.50 per head per day to feed out to 127 days old and the target weight is 129 kg/284 lbs.

If a calf is born at 40 kg/88lbs and gains .71 kg/d (1.56 lbs/d) it would take (129kg/284lbs-40 kg/88lbs = 89 kg/196 lbs of total weight gain ) (89 kg/196 lbs total weight gain/.71 kg/d (1.56lbs/d) = 125 days to hit 129 kg/284 lbs. Now lets say in that 127 day period the calf gains .81kg/d (1.79 lbs/d).

The math would be as follows: (129kg/284lbs-40 kg/88lbs = 89 kg/196 lbs of total weight gain (89 kg/196 lbs total weight gain/.81 kg/d (1.79lbs/d) = 109 days to hit 129 kg/284 lbs. The difference then is 125d-109d = 16 days. In other words if a calf gains 0.07kg/d (.154 lbs/d) more, it will hit the target of 129 kg/284 lbs, 16 days sooner. If it costs $1.50 per day to feed the calf it would equate to $24.00 more in savings in terms of decreased days on feed. Can you afford to spend $24.00 more on a full fat colostrum replacer with pure colostral fat?

By now it should be evident how important brown fat is to the newborn and the role colostrum plays in thermoregulation. It does not mean a colostrum replacer can’t be used but it is important to be sure it is made from whole bovine colostrum and is not defatted or made with other fat sources.

 

 

Mike Nagorske, DVM.

Director of Research, SCCL
[email protected]

Calves are a unique species in how they rely on colostrum ingestion to provide immune protection for the first months of life. Are refractometers an accurate way to quickly and easily measure immune transfer in individual calves?

Adequate colostrum ingestion is the single most important determinant of health, survival, performance and therein profitability in calf’s life. Passive Transfer is commonly used to describe the phenomenon by which a calf acquires its immunity from the dam via colostrum.

My calves received colostrum. How can I now verify that my calves have enough immunity?

Many producers often question if there are visual ways to determine if a calf fails passive transfer; however, it usually requires pulling a blood sample, centrifuging the sample to collect serum and either directly or indirectly measuring the level of IgG.

The indirect way to measure IgG in the serum is by utilizing an optical or digital refractometer which measures serum total protein (STP). This method is considered a calf side test because the blood can be collected on a particular day, centrifuged, and the serum can be placed on the refractometer with the result being known right then.

Because serum total protein is readily analyzed and available on the farm, many producers have relied on this test to determine the level of passive transfer in calves. While this has been practiced for many years and it is regarded as a useful tool, the results have frequently been misinterpreted due to limitations of the test.

It is important to understand how a refractometer works and the composition of the serum tested before heavily placing emphasis on data from STP. Believe it or not, refractometers were originally designed for use in the wine, beer and maple syrup industries to measure the amount of sucrose or sugar in water. The refractometer itself, whether it is optical or digital, relies on a light source and prism.
Brix refractometers have been validated for use on farm to indirectly measure IgG content in both colostrum and serum.

In calves specifically fed maternal colostrum, use of serum total protein has proven to be highly correlated to levels of IgG in the calf and also used to identify failure of passive transfer (FTP).
However, the serum total protein test is not meant to determine passive transfer status of individual calves.

The serum total protein testing is not meant to answer questions regarding passive transfer status on individual calves. Rather, the correct way to utilize this test is on a population level and to answer one question: Is my colostrum management program likely working or not working? Godden et al., 2008 best describes this and indicates that results need to be interpreted on a group or herd basis and will accurately reflect the relative proportion of calves with FPT.

How do I accurately perform the test and what do the results mean?

To perform it properly, the serum samples should be collected from at least 12 clinically normal calves
(without scours or respiratory disease) between 24 hours and 7 days of age. Godden et al;, 2008 also mentions two cutoff methods for determining the proportion of calves with FTP where one goal is for 80% or more of calves tested to meet or exceed 5.5 g/dL or another in that 90% or more of calves be above a cut-off of 5.0 g/dL.

It is recommended then when a disproportionate number of calves have FPT, that an investigation be performed to determine problems with the colostrum management program.

Furthermore, this could involve utilizing the gold standard method for determining true IgG concentration in the serum where radial immunodiffusion (RID) testing be performed.

“…the correct way to utilize this test is on a population level and to answer one question: Is my colostrum management program likely working or not working?”

Can I use a refractometer to test my calves after feeding colostrum replacer products?

If a colostrum replacer is fed, serum total protein testing should not be utilized to determine passive transfer status even on a population level. A recent study conducted by Lopez et al,. (2021) looked at the accuracy of the use of serum total proteins for maternal colostrum fed calves and calves fed a colostrum-based colostrum replacer. Serum IgG was inaccurate or poorly correlated with serum IgG when considering calves fed a colostrum-based colostrum replacer.

Therefore, because results are widely variable and inaccurate, it is not recommended to utilize serum total proteins when monitoring or determining passive level status in calves fed colostrum replacer. It is recommended instead to perform radial immunodiffusion testing.

Which other factors can affect serum total protein levels and alter the results from testing with a refractometer?

It is also important to consider the composition of serum and some of the limitations of what is being tested in the serum. When it comes to trying to understand passive transfer status based on serum total protein, we must remember the following assumptions:

1. Colostrum solids are about 50% proteins (up to half of which is IgG1).
2. All colostrum proteins are nonselectively absorbed into the bloodstream (not only IgG).
3. Calves that suckle large amounts of colostrum can be identified by measuring serum total protein levels and calves with high total proteins have high IgG1 levels. While this is somewhat correct, it is also important to remember that serum total proteins are taken after colostrum ingestion.

Serum total protein therefore will also be affected by the following:

1. Presuckle levels of serum proteins
2. Amount of protein absorbed (as described in terms of 1). The more colostrum absorbed, the more protein absorbed
3. The higher the level of IgG in colostrum, the higher the serum proteins.
4. Timing of blood collection.

As to the presuckle levels of serum proteins, some colostrum fed calves have lower total proteins than colostrum deprived calves (Tennant et al AJVR 1969 30: 345) likely due to differences in albumin concentrations which can vary form 1.9-3.4 g/100 ml in day old calves (Schultz et al 1971, 35:93). This is to a large degree why calves serum total protein can read high even before colostrum ingestion.

The figure below outlines the many other proteins in serum. As with measuring the total solids content of colostrum measuring the total proteins in calf serum assumes that if the serum protein is high that the serum IgG is high and visa versa. However, since the IgG is only one component (and not the major component), changes in the other fractions also affect the total serum protein level. In other words, if for example a calf is born with an initially higher albumin level, the serum total protein may read higher and IgG may not be indicative of the higher protein level.

In summary, it is important to measure immune status of our calves, however the most practical and accurate means of doing this is at the herd level. Rather than getting fixated on one individual calf’s result, lets ask ourselves, do I have healthy calves? By looking at immune transfer at the herd level, it can give us insight into the colostrum program and health status of our calves.

Serum Total Protein Tests

DO’S	DON’TS
✓ Evaluate a herd status of at least 12 calves ✓ Understand category levels ✓ Draw samples between 12- 36 hours ✓ Use it to get a general evaluation of your maternal colostrum program	× Evaluate individual calves × Draw samples after 48 hours or on sick calves × Use STP to pay calf premiums × Use it to test colostrum replacer program success

 

Mike Nagorske, DVM.

Director of Research, SCCL
[email protected]

Newborn lambs and kids require colostrum at birth as a sole source of nutrition. When the dam cannot provide enough high quality colostrum, producers now have a highly effective and convenient alternative.

 

What is colostrum?

Colostrum is the first secretion produced by the doe/ewe’s mammary gland, and is the key and most important source of nutrition for the newborn. This milk is an important component for the survival and health of the offspring, not only because of its high nutritional values, but also because it is a source of antibodies that helps development and protects from infections. Since it is an energy-rich source, it helps the newborns maintain their body temperature in order to survive. The colostrum also contributes to the kid/lamb body and organ growth and development, as well as their future milk production performance due to its diverse components such as bioactive factors, cells and hormones. Feeding high-quality colostrum in sufficient quantity immediately after birth protects the neonate, both in the short and long term. Ideally, each newborn should be fed colostrum as soon as possible (within 30 minutes) after birth, taking care not to exceed more than two hours after birth for this first ingestion.

Because of the type of the ruminant’s placenta, the transfer of passive immunoglobulin from the mother to the foetus during pregnancy is impaired. Therefore, colostrum is the sole source of initial acquired immunity. Thus, the percentage of newborn kids/lambs’ survival depends on the access of colostrum during the first hours after birth.

When and how much colostrum?

Morbidity and mortality of kids and lambs are a global challenge that affects their welfare and productivity on the farm. Providing adequate quantities of colostrum is key to reducing losses that may occur due to infectious diseases that harms newborns. In most intensive dairy farms, lambs and kids are separated from their mothers immediately after birth and transferred to an artificial rearing unit. Early access to colostrum that is of good quality, enough quantity and is fed as quickly as possible, is essential for their health, since the lack of adequate passive immunity from the dam to the offspring is the main cause of morbidity and mortality in small ruminants.

Lambs and kids must receive at least 50 ml/kg of good colostrum (>25% Brix) as soon as possible after birth. This first feeding must not exceed 2 hours after nascency. In 24 hours, a newborn lamb/kid must receive the equivalent of 200 ml/kg body weight in colostrum (AHDB) or at least 30g of IgG. Thus, a 3 kg newborn should get ideally at least 600 ml of colostrum on its first day of life. This amount can be divided into two or three meals. However, if this amount is not possible, the suggested intake to secure adequate passive immune transfer is between 10-15% of the newborn body weight. That means that the 3 kg kid/lamb should get at least 450 ml divided in two to three times during the first day of life.

Difficulties regarding colostrum may arise, due to poor quality, lack of adequate quantity, or even due to short of farm staff to help providing colostrum quickly. All these problems can harm newborns’ health and expose them to infections and low development in their first months of life. As a result, protocols have been developed for the administration of dried colostrum, which can help ensure that newborns receive sufficient amounts of high-quality colostrum.

Can I use dried cow colostrum?

The use of commercial bovine-dried colostrum already exists in several rearing units. Studies have shown the high efficiency in the absorption of IgG antibodies that originate both in bovine colostrum and sheep/goat colostrum. This means that cow colostrum can be provided to newborn kids and lambs and show excellent results.

Using a whole bovine colostrum substitute reduces preweaning morbidity and mortality, as well as decreases the use of antibiotics. This results in a better daily weight gain, and increases the number of lambs/kids marketed. In addition, colostrum is known to protect against diarrhea, improve overall health and weight gain.

 

 

Juliana Mergh Leão, DVM, MSc., DSc.

Veterinary Technical Specialist, SCCL
[email protected]

 

Haim Leibovich, PhD.

Consultant, Small Ruminant Production Systems
[email protected]

 

Joana Palhares Campolina, DVM, MsC, DsC.

Veterinarian/Research Veterinarian
[email protected]