|Grings E E,|
|Adams D C, - UNIVERSITY OF NEBRASKA|
|Short R E,|
Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 22, 1994
Publication Date: N/A
Interpretive Summary: Efficient rangeland beef production is influenced by the ability of forage to meet the nutritional demands of the grazing animal. Understanding the diet selection process in free-grazing livestock aids in our knowledge of nutrient use. Esophageally cannulated animals are often used as a research tool to evaluate diet quality of grazing livestock. This study was conducted to evaluate the nutritive value of diets selected by esophageally cannulated suckling calves and mature animals to determine if nutrient composition differed in diets of the two classes of cattle. Diets of suckling calves were greater in nutritive quality than were diets of older animals during June and July as measured by increased protein and decreased fiber. These differences were not observed in September, October, or December. We conclude that suckling calves selected diets of higher quality than did mature steers when forage quality allowed selective behavior. This information indicates that animals of the appropriate age class should be used to evaluate diet quality in nutritional experiments. The higher quality of calf diets may also explain differences in growth patterns between calves and older animals grazing similar rangelands.
Technical Abstract: A study was conducted over two years to evaluate the quality of forage selected by suckling calves compared to mature steers. Diets were collected from esophageally cannulated suckling calves or from steers that were two-years-old or older. Sampling was conducted in June, July, September, October, and November. Diets of esophageally fistulated suckling calves consuming range forage (beginning 115 to 136 days of age) were 24% greater in crude protein, 4 to 6% less in NDF, 3 to 13% less in ADF and 9 - 28 % less in ADL than those consumed by mature steers in June and July. We conclude that suckling calves selected diets of higher quality than did mature steers when forage quality allowed selective behavior.