Balanced nutrition, age grouping, keys to efficient winter cattle feeding

News
Nov 11, 2011
by WLJ

Drought-ravaged pastures and tight hay supplies mean that cattle producers must take extra care this winter to balance the right amount of forage and supplement for their breeding females, especially the young animals.

“Two-year-old first-calf heifers are being asked to continue to grow, produce milk, keep the reproductive tract in good repair, and have enough stored body energy to return to heat cycles in a short time frame,” said Glenn Selk, Oklahoma State University Cooperative Extension emeritus cattle specialist.

The heifers must fill all these energy demands at a time when their mouth is going through the transition from baby teeth to adult teeth.

“If these young animals are pastured with larger, older cows in the herd, they very likely will be pushed aside when the supplements are being fed in the bunk or on the ground,” Selk said. “The result of these adverse conditions for the heifers very often is a lack of feed intake and lowered body condition.”

Lowered body condition, in turn, can result in delayed return to heat cycles, as well as a later calf crop or smaller calf crop the following year.

North Dakota State University (NDSU) data of commercial cow herds recorded over a 21-year period illustrated the differences in size and body condition of very young cows and very mature cows compared to cows in the prime of their lives. The NDSU data clearly showed that the average 2-year-old animal is about 20 percent smaller than full-grown herd mates.

“There is little wonder that the younger cows get pushed away from feed bunks, hay racks or supplements fed on the ground,” Selk said. “The results of the size differences and the need to continue to grow are manifest in the lower body condition scores noted in the very young cows. At the same time, the very old cows are experiencing decline in dental soundness that makes it difficult for them to maintain feed intake and, therefore, body condition.”

Over the 21-year NDSU data set, the 2-year-old cows and the 10-year-old and older cows were significantly lower—0.3 or more units—in body condition score than middle-age cows.

Consequently, Selk said it makes sense to sort very young cows with any very old cows that were not culled from the herd previously and provide them with a better opportunity to compete for feed supplies.

“By doing so, the rancher can improve the rebreeding percentages in the young cows and keep the very old cows from becoming too thin before culling time,” he said.

Based on the NDSU data, there are three logical groups of cows to be pastured together for feeding efficiency: •Group 1 – The first-calf heifers. They have higher nutrient needs than other cows that are not growing, but are too small to compete with larger, older cows for the supplement. •Group 2 – Cows age 10 years and older and secondcalf heifers. In addition, this group should include any of the middle-aged cows that were thin and needed extra supplement. Cows that were Body Condition Score 4 or less would be considered. •Group 3 – The remaining cows in the herd. This is the group that is mature in size and in adequate condition to enter the winter feeding period in at least Body Condition Score 5.

“If splitting animals into three groups is not possible, putting the first two groups together would be the logical combination,” Selk said.

“Ranchers then want to be certain that the feeding program is adequate to have cows in each group calve in Body Condition Score 5 or 6 next spring.” — WLJ

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