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University of Missouri
DROUGHT INFORMATION |
Reviewed July 26, 2005
Limit-Feeding Concentrate Diets to Beef Cows
Continued dry conditions throughout the Midwest have prompted many cow-calf operators to begin planning for the pasture and hay shortages that will likely face their beef herds. Scarce forage can have dire ramifications for those that are unprepared. Reduced reproductive performance is usually the primary threat. An excellent strategy to spare forage resources is to reduce nutrient requirements of breeding females. Early weaning has been successfully used as a measure to spare cow body condition and reproductive performance, as well as pastures and other feed stocks, during drought conditions. There are a number of excellent resources on this topic that can be accessed via the world wide web. Web addresses for several of them are included at the end of this message. Please consult them for specific issues related to early weaning as you have need. They include: preconditioning, facilities, processing, feeding, and treating sick calves. One particular point with regard to early weaning that is not addressed with any depth by those web resources is specific diets and feedstuffs that are suitable for early-weaned calves. That is by design, as feedstuff availability varies widely across the country. We are fortunate in Missouri to have access to many commodity and byproduct feeds which are ideal for this task; however, we really need to consider feeding the early weaned calf in two distinct phases. Early weaning is typically applied when the calf is at least 60 days of age and has been suckling up to that point. The rumen of an animal of that age is nearly fully developed and dry feed consumption can be facilitated with proper management. The first phase of early-weaning nutrition concerns the 7 to 14 day immediately post-weaning. It is very much like the receiving phase of a stocker/backgrounding operation. Immediately after weaning, specialized diets and management are required to 1) slowly adapt the calf to a dry diet and 2) facilitate normal immune system function. It is important to keep in mind that ruminal microbial populations can require up to 14 days to completely adapt to a new diet. Therefore, the newly weaned calf should be fed a diet that mimics, as closely as possible, feeds contained in the pre-weaning diet. Milk will obviously not be a part of this equation; however, we can still do a reasonably good job of adapting the suckling calves rumen to a new diet regime without causing undue digestive upset. Premium quality grass hays are an essential part of the post-weaning phase of nutrition. These forages should be offered free-choice and in the long stem form. The long particle size stimulates ruminal motility and encourages extensive rumination (cud chewing); these factors are vital to achieving a smooth transition from an immature rumen to a fully functional one. It is also important that calves be introduced to concentrate feeds at this point. During the post-weaning phase, calves are predisposed to low intake and disease challenge. Increasing the energy density of the diet can help to alleviate these potential problems. Concentrate feeds should be selected that complement the basal forage. That is, concentrate feeds should be low in starch, high in fiber, and moderate in protein during the post-weaning phase. Feeds that fit into this category are cottonseed hulls, soybean hulls, corn gluten feed, distillers dried grains, rice meal, etc. Corn and other high-starch feeds can also be feed to newly weaned calves, however care should be taken to limit the amount. In general, corn should be fed at 0.25% of body weight or less during the 1 to 2 weeks post-weaning. Avoid high-moisture feeds in the post-weaning ration. The reason for this is that they are unfamiliar to the calf and, as a result, intake is often too low to sustain the calf's high nutrient demands. Examples of feed that fit into this category are silage, wet gluten feed, wet distillers grains, and ensiled grains. Feeds extremely high in moisture, such as lush pasture, can adversely affect the calf during the post-weaning phase from the standpoint that the calf is unable to consume enough dry matter to meet its nutrient requirements. Calves will only consume 0.5 to 1.5% of their body weight in dry matter during the post-weaning phase; therefore, the ration must be fairly nutrient-dense. In general, the post-weaning phase diet should contain 13-15% crude protein , 0.75 Mcal/lb NE maintenance, and 0.44 Mcal/lb NE gain on a dry matter basis. The ration should 82 to 90% dry matter. Energy values are the rough equivalent of 68% TDN. This diet should be maintained until a stable intake level is reached by 85 to 90% of the cattle under early weaning management. The second phase of early weaning nutrition can be commenced once stable intake levels have been reached on the post-weaning diet. As calves enter this feeding phase, they should be slowly adapted to a ration containing 50 to 80% concentrate over a period of ten days to two weeks. Rations containing large proportions of high-fiber byproduct feeds are the easiest to manage in this circumstance. These should be formulated to contain 12 to 14% crude protein, 0.6 Mcal/lb NE maintenance, and 0.35 Mcal/lb NE gain on a dry matter basis - in short the calves should be fed to gain from 2.0 to 2.4 lbs. per day. Conversion efficiencies are extremely good at this stage of the calf's life, ranging from 4.3 to 5 lbs of dry matter consumed per pound of gain. This is the time to adapt calves to high moisture feeds like silage. It can be accomplished by providing cattle with the opportunity to select these feeds in addition to their normal diet. Once consumption has reached a significant level (i.e., 0.5% body weight), high-moisture feeds can be substituted into the diet in favor of other feeds. This is also the time to consider implants and ionophores for the calves - a growth promoting implant (feeder cattle only; no replacement heifers) is an excellent investment in the calf's growth rate and ionophore antibiotics will promote improved feed efficiency and gain.
Early Weaning Web Resources
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KC Olson, OlsonKC@missouri.edu 573-882-7289 College of Agriculture Food and Natural Resources |
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