With calving in full swing and Mother Nature throwing some curve balls, ensuring newborn calves receive high-quality colostrum is more critical than ever.

Introduction

Colostrum, the first milk produced by the dam, is rich in immunoglobulins (antibodies), essential nutrients, and bioactive components that are vital for the health and survival of neonatal calves. The timely intake of adequate colostrum is crucial for passive immunity transfer, protecting calves from diseases and setting the foundation for robust growth and development.

The Importance of Colostrum in Beef Calves

Newborn calves are born without a fully developed immune system, making them susceptible to various pathogens. Colostrum provides the necessary antibodies, primarily Immunoglobulin G (IgG), to safeguard against infections during the early stages of life. Research indicates that calves require approximately 300 grams of immunoglobulins (IgG) within the first day of life to achieve excellent passive transfer. The absorption of these IgGs is highest in the first 2 hrs of life. Producers should be aware of this and strive to ensure calves are receiving colostrum from the dam or as a supplement/ replacer in a timely fashion. Beyond immunoglobulins, colostrum contains elevated levels of fat, protein, vitamins (such as A, D, and E), and minerals compared to regular milk. These nutrients are essential for jumpstarting the calf’s metabolism, stimulating digestive activity, and supporting overall vitality.

Dr. Lisa Gamsjäger’s Research Findings

Dr. Lisa Gamsjäger, a researcher specializing in pre-weaning ruminant health, has focused her studies on the transfer of passive immunity and neonatal vaccine strategies. Her work emphasizes the critical role of colostrum not only in providing antibodies but also in delivering growth factors and bioactive components that influence gut health and metabolic programming. Dr. Gamsjäger’s research suggests that even when calves receive sufficient antibodies to prevent clinical Failure of Passive Transfer (FPT), inadequate intake of these additional colostral components can lead to suboptimal growth and increased susceptibility to stressors such as weaning and transportation.

In a collaborative study, Dr. Gamsjäger and her colleagues investigated the impact of colostrum management on beef calves. The findings highlighted that calves receiving high-quality colostrum shortly after birth exhibited improved health outcomes and reduced incidence of diseases. This underscores the necessity for beef producers to adopt effective colostrum management practices to enhance calf performance and welfare.

Challenges in Colostrum Management for Beef Producers

Unlike dairy operations, where colostrum quality can be directly measured using tools like Brix refractometry, beef producers often lack the means to assess colostrum quality on-farm.

Therefore, implementing best management practices is essential to ensure calves receive adequate and high-quality colostrum. Factors to consider include:

• Dam Nutrition and Health: Proper nutrition and health of the dam during gestation significantly influence colostrum quality and yield.
• Timely Intervention: Calves should ingest colostrum as soon as possible, preferably within the first two hours post-birth, to maximize antibody absorption.
• Environmental Conditions: Adverse weather, muddy environments, and stress can hinder a calf’s ability to nurse effectively, necessitating manual colostrum administration.

Decision Process for Colostrum Supplementation or Replacement

To assist producers in making informed decisions regarding colostrum supplementation or replacement, the following protocol is recommended:

• Birth Intervention Assessment:
  • No Assistance or Minor Difficulty: Monitor to ensure the calf stands and nurses within two hours.
  • Major Difficulty, C-Section, or Abnormal Presentation: High risk for FPT; consider immediate colostrum supplementation or replacement.
  • Dam-related Issues (e.g., death, poor udder conformation, inadequate bonding) or Weak Calf: Provide full colostrum replacement promptly.
• Initial Monitoring (0-2 Hours Post-Birth):
  • Calf Standing and Nursing Vigorously: No intervention needed; continue to monitor.
  • Calf Not Standing, Lacks Suckle Reflex, or in Adverse Conditions (e.g., mud, twin birth): Administer colostrum replacement immediately.
  • Calf Attempting but Failing to Nurse Successfully: Provide an appropriate dose of colostrum supplement.
• Follow-Up Monitoring (6-12 Hours Post-Birth):
  • Calf Nursing and Bonded with Dam: Continue regular monitoring.
  • Calf Not Nursing: Administer a second feeding of colostrum supplement or replacement as necessary.
  • Assess Additional Needs: Determine further colostrum requirements based on the calf’s size and health status.

By adhering to this structured colostrum management protocol and incorporating insights from recent research, producers can enhance calf immunity, reduce disease incidence, and promote optimal growth and development. Proactive colostrum management is a pivotal investment in the long-term productivity and profitability of beef operations.

Dr. Travis White

SCCL, Director of Veterinary Technical Services

Introduction

Newborn calves have an underdeveloped immune system and no circulating maternal antibodies, leaving them highly susceptible to infectious diseases. Unlike humans, where passive immunity is transferred through the placenta, the synepitheliochorial placenta of cattle prevents the transfer of immunoglobulins from the dam to the fetus (Peter, 2013). As a result, calves are born without humoral immunity and rely entirely on colostrum intake for passive immunity.

Immunoglobulins and their role in calf immunity

Introduction

Colostrum, rich in nutrients and antibodies, is essential for providing passive immunity to newborn calves. The concentration of Immunoglobulin G (IgG) in colostrum is a key factor in determining its quality, and Brix refractometry is commonly used on farms as an indirect measure of IgG concentration in colostrum. Feeding calves with high-quality colostrum during the first hours of life is crucial for ensuring adequate IgG transfer, as calves strictly rely on it to develop disease resistance (Figure 1). However, the quality of maternal colostrum can vary significantly among cows within the same herd. In this context, enriching maternal colostrum with a colostrum replacer has emerged as an effective strategy to improve quality by increasing levels of IgG, nutrients, and bioactive compounds.

Figure 1. Graphical representation of the transfer of passive immunity mechanism in newborn calves.

 

Brix % and variability of maternal colostrum

 

This has been a general guideline for many years for a Holstein calf, which should receive 10% of its body weight (.1 X 40 = 4L) at 22% Brix (50 g IgG/L x 4 = 200 grams of IgG). However, new recommendations indicate that calf morbidity and the rate of failed passive transfer decrease when more antibodies (IgG) are provided in the colostrum. These new recommendations now suggest providing 300 grams of IgG to achieve excellent passive transfer. What does this mean in terms of Brix? It means that we need to raise the standards on the farm to select colostrum with Brix levels higher than 24%. However, ensuring consistent colostrum quality in a herd is very difficult, as there are conditions that cause significant variability among cows in the same herd. This variability is influenced by factors such as age, breed, nutrition, prepartum vaccinations, milk production, and the interval between calving and colostrum collection, among others (Moore et al., 2005; Conneely et al., 2013). In a study conducted in 8 dairy farms in the United States (Figure 2), which analyzed IgG concentration in maternal colostrum through refractometry, Brix percentages ranged from 12% to 32%, with an average of 23.8%, indicating the vast variability in IgG concentration among cows (Quigley et al., 2013). This study by Quigley et al. (2013) highlights the challenge of relying exclusively on maternal colostrum to ensure adequate quality and, therefore, correct passive transfer of IgG in calves.

 

 

Figure 2. Adapted from Quigley et al. (2013). Distribution of total protein in maternal colostrum estimated through Brix refractometry

 

To address this variability and improve the quality of maternal colostrum, an effective strategy is the enrichment with a colostrum replacer. This strategy presents itself as a viable alternative to overcome the limitations associated with differences in the quality of maternal colostrum available on the farm, thus ensuring greater consistency in the transfer of essential antibodies for the immune development of the calves.

 

 

Benefits of enriching low – quality maternal colostrum

There is scientific evidence supporting the usefulness of enriching maternal colostrum. In a study conducted in Canada, researchers investigated whether low-quality maternal colostrum could be enriched with bovine colostrum replacer to reach adequate serum IgG levels in newborn calves (Lopez et al., 2023).

In this study, the researchers fed the calves maternal colostrum with a Brix content of 15.8% (equivalent to 30 g/L of IgG), achieving an average serum IgG concentration of 11.76 g/L (Figure 3). This IgG concentration falls within the “fair” category on the most recent passive transfer of immunity classification scale (Lombard et al., 2020). The maternal colostrum was then supplemented with 551 g of colostrum replacer (Saskatoon, SK, Canada; SCCL) to bring the IgG concentration up to 60 g/L. Calves that were fed the combination of maternal colostrum + colostrum replacer had an average serum IgG concentration of 19.85 g/L, thus moving from the “fair” to the “good” category on the passive transfer of immunity scale of Lombard et al. (2020). Furthermore, 18.8% of the calves fed maternal colostrum with 15.8% Brix experienced failure in the transfer of passive immunity. However, when that colostrum was enriched with colostrum replacer, 0% of the calves showed failed passive immunity (Lopez et al., 2023). In another similar study conducted in Brazil, calves were fed maternal colostrum with 25% Brix or maternal colostrum that initially had 20% Brix but was enriched to 25% Brix using a colostrum replacer (Saskatoon, SK, Canada; SCCL) (Silva et al., 2024).

The final results of this study found no differences between the calves regarding serum IgG concentration, total serum protein, apparent efficiency of IgG absorption, concentrate intake, daily weight gain, body weight, or variables related to the health status of the calves.

Figure 3. Modified from Lopez et al. (2023).

These results demonstrate that improving the quality of maternal colostrum through enrichment with a colostrum replacer is possible, as evidenced by the lack of differences in serum IgG levels, health status, and productivity in the calves across both treatments. At SCCL, there are a series of recommendations for enriching colostrum on the farm. It is considered that any colostrum with a Brix percentage of 22% or lower should be enriched to achieve an adequate IgG mass. Table 1 shows the classification of colostrum based on its Brix percentage and the corresponding recommendation.

Table 1. Recommendations for enriching maternal colostrum with a colostrum replacer.

To know exactly how much colostrum replacer we need to add to our maternal colostrum, we first need to determine the Brix percentage of the colostrum we are working with. This can be done using a refractometer, which will quickly provide us with a reading based on the quality of our colostrum. Additionally, we need to set the target Brix percentage we want to achieve with the enrichment. Our goal should always be to obtain colostrum that falls between 25-30% Brix. Once we know the Brix percentage of our colostrum (what we have) and our enrichment goal (what we want to reach), we can use Table 2 as a reference to determine how many grams of SCCL colostrum replacer we need to add to our maternal colostrum.

 

Table 2. Colostrum powder calculations to enrich fresh colostrum.

Finally, it is essential that when enriching colostrum, a colostrum replacer derived directly from maternal colostrum is used. This ensures that the product retains the essential characteristics of natural colostrum, without the addition of additives or the removal of crucial components. An appropriate replacer should maintain the natural levels of fat, protein, immunoglobulins, and bioactive compounds present in maternal colostrum. In this way, it ensures that the calves receive nutrition and immune protection like what they would obtain from natural maternal colostrum, maximizing the benefits for their health and development.

Figure 4. Key points of an adequate colostrum management protocol.

Conclusion

Lucía Pisoni, Juliana Mergh Leão, José María Rodríguez, Isela Ceballos, and Marina Godoy

Department of Clinical Research, The Saskatoon Colostrum Company Ltd., Saskatoon, Canada  

The Importance of Colostrum for Dairy Goat Kids

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]