A cow herd’s greatest nutrient requirements occur immediately after calving and continue through peak milk production.

During this period, a cow uses the majority of the nutrients it consumes to produce milk to sustain a hungry, growing calf. After that, the cow uses the nutrients to regain body condition, and as a last priority, to repair its reproductive system.

“Cows in poor body condition at the time of calving likely will have difficulty rebreeding,” cautions Carl Dahlen, North Dakota State University Extension Service beef cattle specialist. “Cows often lose some body condition in the months after calving, and the goal of a solid nutrition program should be to minimize this loss in condition.”

Feeding lactating cows to their increased nutrient requirements is the best way to minimize loss of body condition. Every herd has cattle at a variety of ages and body conditions, and every herd has its limitations in the way it can group cows before and after calving.

Minimizing the competition in the feeding area is one way to help ensure cows have access to feed. Thin cows, cows that had difficult births and first-calf heifers may be pushed away from feed by older cows or cows in better condition. If facilities are available to feed different groups of cows, heifers and thin cows should be fed separately from mature cows, Dahlen advises.

The importance of these increasing nutrient needs is even greater in heifers calving for the first time. In addition to the increased demands of lactation, this class of cattle has more difficulty calving and still is growing. These factors add up to the heifers needing a greater amount of time to start having estrous cycles after calving.

Delayed estrous cycles after calving result in delayed breeding, This is the basis for a common recommendation to calve heifers two weeks prior to other cows in the herd. Being the first to calve means the heifers get more attention, producers can dedicate more time to heifers having problems, and the heifers have more time for uterine repair and resumption of estrous cycles.

Reproductive performance and performance of calves is reduced in thin cows. However, gaining body condition in thin cows after calving is expensive in terms of feed energy and finances and should be approached with caution, Dahlen says. Improving body condition is much easier before calving and typically cheaper while the cows are on pasture.

While difficult to accomplish, thin cows may gain body condition after calving. But overfeeding an entire herd to allow thin cows to gain weight will result in overfeeding the cows in adequate body condition. In addition, cows in good body condition may eat more aggressively and keep thin cows from getting the extra feed delivered for them. If producers decide to feed thin cows to gain weight, the best option is to feed a group of thin cows away from the main herd.

Another area of the nutritional program that needs emphasis at this time of the year is mineral nutrition. Minerals are important for reproduction, health and growth, and these are all areas that drive profit potential in beef operations. Producers should provide adequate mineral supplements to all classes of cattle.

Producers feeding a mixed ration may consider adding ionophores to cow diets. Ionophores are feed additives that alter bacterial environment in the rumen. Ionophores can reduce the feed consumption of cows fed high-forage diets without changing cow performance, thus improving feed efficiency.

“In addition, and possibly more importantly at this time of year, is the effect ionophores can have on coccidiosis-causing organisms,” Dahlen says. “Coccidiosis can be devastating to calf health, producing severe scours and death if left untreated. Feeding ionophores can reduce the prevalence of coccidia in cows, thus reducing potential exposure in the calves.”

Nutrient content of feeds can vary depending on the field, cutting, year and/or load of feed purchased. The most accurate rations will be formulated with nutrient values of feed used on individual operations.

Also, producers should try to estimate the amount of loss on their operation and increase the feed delivered to their cattle by the amount of feed that is wasted. Each method of feeding (on the ground, in bale rings, in a bunk, etc.) has a different amount of loss. Losses can be as high as 40 percent.

For information on nutrient requirements of cows, cow rations or feed testing, producers should consult their Extension agent or a nutritionist.

NDSU Agriculture Communication - March 28, 2011