CHANGES IN BODY WEIGHT OF STOCKER CATTLE DURING THE ADAPTATION PERIOD ON WINTER WHEAT PASTURES

Authors: Phillips, William; Brown, Michael; Appeddu, Lisa

Submitted to: Proceedings of the National Conference on Grazing Lands
Publication Type: Proceedings
Publication Acceptance Date: 10/1/2000
Publication Date: 12/1/2000
Citation: Phillips, W.A., Brown, M.A., Appeddu, L.A. 2000. Changes in body weight of stocker cattle during the adaptation period on winter wheat pastures. Proceedings of the National Conference on Grazing Lands. p. 375-381.

Interpretive Summary: Grazing livestock are cautious of novel feeds when they are first introduced into the diet. Each year millions of stocker calves are shipped to the Southern Great Plains to graze winter wheat, which is a novel and unique forage, before entering the feedlots for finishing. The objective of this experiment was to determine how rapidly the stockers begin to consume wheat forage and the impact low forage intake has on stocker performance. Stockers do not readily consume winter wheat forage and need 14 to 21 days to include enough wheat forage into their diet to make positive weight gains. Development of managerial schemes to shorten this adaptation period would increase stocker cattle production.

Technical Abstract: Each year millions of stockers calves are shipped to the Southern Great Plains (SGP) to graze winter wheat pastures before entering near by feedlots for finishing. Many of these stockers have never grazed winter wheat forage and may not readily consume it when it is first introduced into the diet. Wheat forage is a unique forage that contains high concentrations of soluble carbohydrates, digestible DM (dry matter), soluble protein, digestible protein and total nitrogen, but if DM intake is low, stockers may not gain any weight. The objective of this experiment was to determine if stocker calves have to adapt to winter wheat forage as a novel forage and if the adaptation period impacts stocker performance. During the winter grazing period, when winter wheat is in a vegetative stage, stockers lost almost 7 kg (15 lbs) in body weight (BW) during the first 14 d of the grazing period. Although positive gains were observed during the second 14 d of grazing period, the stocker calves did not compensate for the poor performance during the first 14 d. In the spring, when wheat forage contains lower concentrations of protein and higher concentrations of fiber, stocker calves still needed 14 d to begin to perform at the anticipated level. From these data, we concluded that stocker calves go through a period of poor performance when first placed on wheat pasture. If the adaptation period can be shortened or its impact mitigated then overall stocker performance would be improved.