Ontario Beef Magazine

February 2019

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Vet On Call: Hold on to your hats – winter calving may be a bumpy ride

By Katharine Found, DVM

The weather this winter has been, for lack of a better word, unpredictable, to say the least. Rain with a bitter cold wind one day, followed by snow, then sunshine and double digits – all within the same week! And if you find yourself in the midst of calving during these fluctuating forecasts, you will want to ensure that your colostrum management is the best it can be for the sake of your calves, your profitability and your sanity.

Colostrum is the first milk produced by the dam and is a critical source of antibodies, energy, vitamins, minerals and growth factors for the newborn calf. Antibodies from the dam do not cross the placenta during pregnancy, therefore newborn calves are born with a naïve immune system – they have zero ability to fight off infections. Therefore, it is essential for the health and survival of a calf that they receive antibodies from colostrum.

During winters such as these, disease pressures are often higher, which can lead to more sick calves if we aren’t paying attention to crucial details. It becomes extremely difficult to keep calving pens clean and dry, no matter how much bedding you seem to add. And, the change in temperatures and humidity often makes ideal ventilation a challenge. We can’t change the weather. Grumbling about it may be good for our stress relief, but it won’t help the calves. There are, however, a number of things within your control that will help to make this calving season a little less challenging.

First, find time, energy and resources to keep pens cleaner and drier. Use a bedding substance that is more absorbable and use lots of it. Corn stalks might have to be saved for a drier time of the year, or be used in conjunction with straw to help improve moisture wicking capacity. Add lots and add it often to maintain dryness. Decreasing the stocking density in the pens will also help to keep pens drier, if spreading cows out is a possibility within your setup.

Next, it is imperative to ensure all calves receive ample amounts of high-quality colostrum from a clean udder, or from a clean bottle or feeding tube. It is well-defined that dairy calves should receive four litres of good quality colostrum within six hours of birth. In this setting, where humans are typically responsible for colostrum feeding, this is a goal that can easily be observed and measured. Beef calves are no different, however, it is much harder to know how much and how quickly these calves acquire their colostrum since we typically allow Mother Nature to control the feeding program.

To manage this uncertainty, more frequent observations may be needed. Whether that is more frequent physical barn checks (at least every four hours), or the installation of calving pen cameras that allow you to rewind to see past events, find a method that allows you to have eyes on the barn more often. All dams should have their udders checked post-calving for visual colostrum quality. Any colostrum that is bloody, or has an abnormal colour, has a bad smell or contains clots or chunks, should be considered unacceptable. In this case, the calf should be given three to four litres of frozen colostrum or sufficient powdered colostrum over the next two to six hours to meet their needs. These feedings can be separated into two to three allotments if necessary, but try to get as much as possible into the calf during the first feeding, for best passive transfer results. Next, if you did not observe the calf exhibiting a strong suckle on an udder that you have checked to have ample amounts of normal looking colostrum, put the calf on the cow and watch it suck. If the calf does not have a strong suckle, supplement with frozen or powdered colostrum immediately.

Having a good supply of supplemental colostrum on-hand is always a good idea, and can literally be a lifesaver, especially during a challenging calving season. It is acceptable to have a stash of frozen colostrum on hand, but if you choose this method, ensure the product was a good quality sample, collected cleanly, frozen immediately and is stored for no longer than eight weeks in a fridge freezer or six months in a chest freezer. The other major drawback to frozen colostrum is the time it takes to thaw and the possibility of decreasing the quality of the product through improper collection, storage and thawing techniques. For best results, colostrum should be collected and stored in one- to two-litre portions in Ziploc freezer bags. Freezing immediately is ideal, but if not possible, the sample should be refrigerated within 20 minutes after collection, and frozen as soon as possible after that. To thaw, the samples should be placed in a warm water bath (50oC) to prevent the denaturing of the proteins.

Alternatively, there are several commercial sources of colostrum powders available on the market that provide the calf with the necessary IgG antibodies required for successful passive transfer. These products vary in price, and similar to most things in life, you get what you pay for. Beef calves need 150 to 200 grams of IgG within the first six to 12 hours of life. Read the labels of these powder products to ensure you are meeting these requirements. Cheaper products usually contain a lower concentration of antibodies and will therefore not meet the calf’s requirements if only one bag is offered. Be sure to read the labels and not just the price tag. Will one bag be enough? How much water and at what temperature do you need to mix with the powder to prepare the colostrum correctly? Mixing these products can sometimes pose difficulty so have a good quality whisk and be prepared to add some elbow grease. These products also have an expiry date and therefore its quality cannot be confirmed after this date.

During challenging calving seasons, it’s a good idea to develop a system to check your colostrum management. Handheld BRIX refractometers can be purchased to allow producers to assess the quality of colostrum from a cow immediately. Simply place a drop of colostrum on the refractometer’s slide and read the level, which is displayed as good, fair or poor. A BRIX reading of 22% or higher is considered good and the colostrum can be used. Anything less than this, you should have a plan developed with your veterinarian on how to proceed appropriately to ensure calves receive enough antibodies.

The transfer of passive immunity can also be assessed by working with your veterinarian to measure serum total proteins. A simple blood sample is collected from a number of calves that are one to seven days of age, and is assessed in the clinic. A reading of 5.6 g/dL suggests successful passive transfer and excellent colostrum management. A value of 5.2 g/dL or less suggests a failure of passive transfer. This type of testing provides a great deal of useful information, but its downfall is that it is historical information. Once you have results, it’s impossible to improve a calf’s score, given that the calf’s ability to absorb antibodies from colostrum ends at 24 hours of age. But what it does allow you do to is work with your veterinarian to identify why calves are not receiving adequate passive transfer and make changes for the future.

Now is also a good time to work with your veterinarian to ensure your vaccination protocols are an ideal fit for the added challenges this calving season may bring. Keeping in mind that colostrum is produced six to eight weeks prior to calving, vaccines administered to cows, intended to prevent calf diseases must be on board prior to this time. Your veterinarian will also be a useful resource to ensure cows are in good health and body condition and are receiving adequate nutrition to ensure they will produce enough colostrum at calving.

When so many things are out of our control, colostrum management is something we can manage that can help make bad days better. Work closely with your veterinarian to have a clear plan for what to do, how to monitor and when to make adjustments. Healthier calves are worth the extra time and effort, every time.

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