MANAGEMENT MATTERS
Next Year’s Planning Begins Now Nutritional, management challenges for a 365-day calving interval Story By Elizabeth Walker for Cattlemen’s News
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ny time cattlemen prepare for calving season, we are preparing for next year’s calving season as well. One of the most important determinants of female rebreeding, other than her future mate’s ability to breed her, is her body condition going into the calving season. A cow’s nutritional status is directly correlated to her calving interval. A cow with a body condition score of less than 4 will take, on aver-
age, 80 days to come back into heat once she calves. On the other hand, a cow with a body condition of a 5 or 6 will take 55 days or less to show heat after calving. A cow that is in a lower condition score will have less likelihood of maintaining a 365-day calving period. On average, depending upon frame score of the cow, one body condition score equates to about 70 to 100 pounds.
Break-even cost of a cow in a BCS of 6 is significantly lower than one in a condition score of 4. Those 200 pounds make a difference in your overall business plan and profits. It takes time, money, and most importantly, nutrients to raise the body condition score of a cow who is in a poor or marginal condition. If a cow is in a BCS of 3 and she is 90 days pre-partum, she will need a feed ration that is a 64-percent total digestible nutrients (TDN) compared to a cow in a 5 BCS, who will require a ration that is 53-percent TDN, to raise or maintain her condition. As a reminder, the TDN of dairy-quality hay is in the 60s.
You have likely heard that the best defense is a good offense, and in this case, the offense is managing the cows so they don’t lose an excessive amount of condition. That will keep you from going on the defense to put several hundred pounds back on her. Sure, just like humans, cows don’t always fit into jeans size, but it can be costly both in terms of added nutrients and in loss of fertility to allow an animal to lose too much weight. When a cow is expected to calve also impacts her dietary requirements. A cow in a BCS of 5 will require an extra 1 percent energy for every degree below 19°F. As temperatures drop below 20°F, expect a cow’s dry matter intake to increase by as much as 10 percent. And, when temperatures drop below 5°F, dry matter intake can increase by as much as 25 percent. A cow in a BCS of 5 or 6 who is adapted to the cold and has a dry hair coat will certainly fare better than a thin cow with wet coat. A non-temperature-stressed cow will normally require 25 percent more feed, 11 percent more energy and 30 percent more protein than a gestating cow. Add cold stress into the mix, and you can easily see why it can be expensive to have a cow in a lower body condition score, especially heading into winter who is expected to calve and rebreed. Forage should be the best route for a gestating or lactating cow, unless you have one who is over-producing milk and as a result has a higher nutrient requirement. You can supplement grazing with good quality hay. If possible, that hay should be unrolled to provide both bedding and greater access to the feedstuff. When cows are eating a forage-based diet, you should not feed corn at more than 2-3 pounds per head per day. Adding that much starch to a forage-based diet will decrease fiber digestion by disrupting the normal, fiber-digesting microbes. If energy is needed, consider a non-starch supplement such as distillers grains or soy hulls. CONTINUED ON NEXT PAGE
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FEBRUARY 2016
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