Early in the new year, I was at a local beef meeting where a group of cattlemen was discussing what they see as an issue with spring calving, that being a small but nevertheless disturbing increase in the number of open cows in the fall. The discussion included producers, extension specialists and researchers and focused on a variety of potential reasons to explain the increase without coming to any consensus as to the extent of the problem or the reasons behind it. While puzzling, this issue serves as a reminder of the need to continually focus one’s attention on the reproductive performance of the cow herd and the importance of proper nutrition in achieving your goals.
As many operations are calving as I write this article or will be in May and June, it is worthwhile to review the relationship between reproductive success and nutritional management. In previous columns (i.e. January 2011 and 2012), I have discussed how nutrient requirements change with stage of pregnancy, as well as with lactation. So without going into detail, it is safe to say that for many of you, the next two to four months (i.e. the last six to eight weeks prior to calving and the period from calving through breeding) are going to be critical for ensuring a successful 2014 breeding season.
When consulting with producers on their pre-calving and pre-breeding feeding programs, high on my checklist is ensuring that the nutrient requirements for pregnancy and lactation are met, particularly that of energy. Failure to meet the increased demand for energy imposed by the developing fetus or initiation of lactation will result in a loss of body condition as the cow compensates by mobilizing body fat stores. It is well established that cows losing weight coming into calving will take longer to return to breeding status (i.e. estrus or heat) while excessive weight loss after calving will extend the anestrus period as well as reduce first-service conception rates.
- More from the Canadian Cattlemen: A midterm checkup for your feeding program
To prevent this weight loss, now is the time to adjust your feeding program. Cows entering the last six to eight weeks of pregnancy will have energy and protein requirements 15 to 20 per cent higher than in mid-gestation while lactating cows will have these requirements increased by an additional 10 to 20 per cent or more. To compensate for these increased needs, an adjustment to either the amount fed or the quality of the ration is necessary. The latter usually means higher-quality hay and/or providing a supplemental energy/protein source. For those relying on early-spring pasture growth to meet these needs, remember that such forage is typically high in moisture, which limits dry matter intake and may not meet the energy requirements of early-lactation cows.
This spring it will be advisable to pay extra attention to body condition at calving as it was a long winter which likely resulted in a higher-than-normal percentage of thin cows and heifers. If this is the case, consider flushing these animals with extra grain about a month prior to breeding.
This is also a time when you want to be on top of your mineral feeding program. Both pregnancy and lactation increase the requirements for many of the essential macro and trace minerals. A good example is calcium. As calving approaches, the cow’s requirement increases dramatically due to the high calcium content of colostrum. Failure to provide adequate calcium or imbalances in the mineral content of the diet can induce milk fever, particularly in older multiparous cows. As well, trace mineral deficiencies can lead to a variety of reproductive issues including prolonged anestrous, reduced conception rates, retained placentas and poor semen quality. Ideally you have had your herd on a complete mineral over the winter that was designed to match your forage feeding program. If so, your animals should be in good shape coming into calving, however, post-calving, it will be important to ensure continued access to a mineral specifically designed for breeding cows.
Herds with a history of reproductive issues such as those listed above can often trace the cause to a specific mineral deficiency such as copper, zinc or selenium. In some cases the cause is as simple as failure to provide a supplemental mineral source while in other cases there can be confounding factors such as high sulphur and/or molybdenum levels in the feed and/or water that tie up trace minerals such as copper and induce a deficiency. In such cases chelated minerals may be a good option. Chelated minerals while more expensive, are better utilized by the animal. Their strategic use can alleviate a deficiency or ensure requirements are met more efficiently than conventional inorganic mineral programs. Most companies involved with selling minerals have products specifically designed to meet the needs of breeding cows including blends of chelated and inorganic minerals for problem situations.
While some may feel that such nutritional fine tuning is not worth the effort or expense, astute cattlemen such as those who inspired this column know that when it comes to a successful breeding program, attention to detail pays dividends, particularly with calf prices at $2 or better.