Significant areas of Western Canada are affected by feed shortages and drought, which means many producers are faced with difficult management decisions for their herd in the coming year.
Many producers will have to consider alternative and even unusual feed sources for both the fall and winter.
I’ve seen media reports on the importance of feed testing and this will be an important year to have your forage and other feeds tested for nutrient value.
However, feed testing is only one important step in the management of the cow herd before the winter feeding period. Feed testing alone will not be useful unless you use those results to design a ration that meets the needs of your cows and heifers through winter. This is definitely a year where the services of an expert in livestock nutrition will be valuable.
Once you have some rations balanced and planned with the help of a nutritionist, the next necessary step will be to monitor body condition scores in your cows and heifers. Body condition scoring is best done as a “hands on” process because it is difficult to carry out visual assessments on cattle, especially with winter hair coats.
Body condition scoring may be necessary to sort cattle into various feeding groups at the beginning of the winter feeding season. Heifers and thin cows may need more energy in their ration and may also require a situation that allows for less competition for feed. It is also a useful tool to fine-tune and adjust rations as the winter progresses.
Numerous research studies have shown the impact of body condition on subsequent fertility. By 70 days after calving, only 55 percent of thin cows will start cycling again. In contrast, 80 percent of cows in moderate condition will be cycling by 70 days post calving and 96 percent of cows that are in good body condition will be cycling at that time. In addition, the first service conception rates may be as much as 20 percent lower for thin cows.
The results are dramatic and can have significant effects on the pregnancy rate in the following year. If the cows aren’t cycling, they cannot get pregnant.
Cows should ideally calve in a body condition score of 2.5 to three and maintain or improve that body condition score during the breeding season on pasture when feed resources are typically less expensive.
However, if thin cows are identified at weaning time, it is important to try to improve their body condition prior to calving. Once cows begin lactating, their energy demands become much higher and this makes it very difficult to “catch up” on body condition after calving. This year’s drought conditions will make feed resources even more expensive and many producers may have to unfortunately consider culling some of their herd to make the best use of the scarce resources available. Obviously this is not ideal and can be very difficult. However, the alternative of having a major problem with too many thin cows and a significant animal welfare problem is unacceptable.
Finally, you may want to consider monitoring your herd’s trace mineral and vitamin levels carefully this winter. Mineral and vitamin supplementation will certainly be part of balancing a ration, but in drought years, it might even be more important to be cognizant of trace mineral and vitamin levels.
In particular, the relationship of low vitamin A levels associated with drought conditions is well established. Vitamin A is manufactured by cattle from a precursor found in plants known as beta carotene. Plants that are green and growing are rich in beta carotene, while concentrates or plants that are growing in drought conditions are usually not a good source of vitamin A and beta carotene. The precursor to vitamin A degrades over time with harvesting, dehydration and storage of forages. Up to 50 percent of the beta carotene may be lost over time.
Newborn calves get almost all of their vitamin A from the colostrum they consume shortly after birth. They are actually born with very low levels of vitamin A and rely on their dam’s vitamin A levels in the colostrum. If a cow has been grazing under drought conditions or fed stored feeds low in vitamin A and not received adequate levels of supplemental vitamin A, the calf will be at a much higher risk of being deficient in vitamin A. Vitamin A is necessary for adequate immune function and normal growth. One study in Western Canada demonstrated that calves deficient in vitamin A were almost three times more likely to die than calves that have adequate levels of vitamin A for their age.
Your veterinarian can submit blood samples from cows during the winter feeding period to test for trace minerals and vitamin levels. These results may help you to monitor the success of your supplementation program and allow you to make adjustments as necessary.
As well, work with your veterinarian and nutritionist to get the most value out of the feed you have available.