The intake and digestibility of intake for lactating angus cows grazing fescue-legume and fescue pastures

Author

Johnny Dale Beaty

Date of Award

12-1977

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

J. W. Holloway

Committee Members

F. F. Bell, J. B. McLaren

Abstract

Forty mature lactating Angus cows were allotted to fescue-legume or fescue pastures. Within pasture quality, cow size was intentionally confounded with pastures so that large cows were bred to large bulls. Each cow was fed 10 g Cr₂O₃ in 263 g of feed at each of two feedings (8:00 a.m. and 5:00 p.m.) per day for 155 days (April 26-September 28). Fecal samples collected were analyzed for chromium and acid detergent lignin (ADL). Forage ADL was estimated by the cage and strip method simultaneously. Regression was used to predict DM intake/day (DMI), digestibility (DIG) and digestible DM intake/day (DDM) for each cow (mean values for period). Digesti-bility of fescue-legume was 4% higher (P < .05) than fescue (58 vs 54%). Cows grazing fescue-legume pastures consumed 2 kg more (P < .01) DM and 1.5 kg more DDM (P < .01) than cows grazing fescue (10 vs 8 kg DM and 5.9 vs 4.4 kg DDM). Larger values for cows grazing fescue-legume resulted from advantages during the last of the period. Only small differences were detected during the first 40 days. Cows on fescue-legume used the extra nutrients to maintain 10 kg more (P > .05) weight, to gain 30 kg more (P < .05) weight, and to gain 2.1 mm more (P < .05) subcutaneous fat, but produced similar amounts of milk (P > .10). Cows on fescue-legume, however, weaned 16 kg more calf (P < .10). Cows grazing fescue-legume pastures had 65% of the variation in forage DM intake accounted for by milk production and seasonal cow weight, while for cows grazing fescue pastures this model accounted for only 44% of the variation in forage DM intake. For cows grazing fescue-legume pastures it appears that cow weight, cow weight change and milk production were much more important in explaining the variation in forage DM intake than they were for cows grazing fescue pastures.

Recommended Citation

Beaty, Johnny Dale, "The intake and digestibility of intake for lactating angus cows grazing fescue-legume and fescue pastures. " Master's Thesis, University of Tennessee, 1977.
https://trace.tennessee.edu/utk_gradthes/7996