Diet quality of suckling calves and mature steers on Northern Great Plains rangelands.

Abstract

A study was conducted over 2 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 in each of 2 years. The forage portion of diets of esophageally fistulated suckling calves (beginning 115 to 136 days of age) were 21% greater (P < 0.01) in crude protein and 5% less (P < 0.06) in neutral detergent fiber relative to those consumed by mature steers in June and July. Diets of calves also contained 14% less (P < 0.01) acid detergent fiber than diets of mature steers in June. There were no differences in diet quality due to age during September, October, and November of either year. We conclude that suckling calves selected diets of higher quality than did mature steers early in the growing season. Forage quality may have allowed selective behavior at this time, low forage intakes of calves may have allowed more time for selection, or exploratory grazing by calves may have resulted in diets with increased nutrient quality in early summer.