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Escape protein supplementation for lactating beef cows and growing calves
Abstract
Grazing trials were conducted utilizing individually supplemented lactating beef cows over a two year period to study the effects of supplemental escape protein on cow and calf performance during the active growth periods of smooth brome and big bluestem. A mixture of bloodmeal and corn gluten meal (equal protein basis) was offered daily to supply 0,.11,.23 and.34 kg $\cdot$ head$\sp{-1}$ $\cdot$ day$\sp{-1}$ of escape protein. Corn starch and molasses were used in the energy control supplement. For the smooth brome study, analyses of data from both years indicated a cubic response (P $<$.05) to milk production and calf daily gain. Relative to the energy control, a depression in cow/calf performance was observed at the.11 kg $\cdot$ head$\sp{-1}$ $\cdot$ day$\sp{-1}$ level of escape protein supplementation. No response to escape protein supplementation (P $>$.10) was observed for the big bluestem study. Fiber analyses of smooth brome forage samples obtained via esophageally fistulated beef cows compared to hand-clipped samples revealed that selectivity occurred to a greater degree in 1987 than 1988 (P $<$.05). Selectivity was similar (P $>$.05) each year for big bluestem. Extrusa samples collected throughout the grazing seasons from both grass species were subjected to a 16 h in situ incubation period. Protein escaping degradation for smooth brome and big bluestem was estimated to range from 7.0 to 14.5% and 22.2 to 30.3%, respectively. In situ, digestion and calf growth studies were conducted to determine the effect of hydrolysis time on feather meal (FTH) protein digestion, percent escape and the optimum quantity of blood meal (BM) addition to FTH necessary for evoking a complementary response. Differences in protein escape, dry matter and protein digestibilities due to hydrolysis time were not significant. True protein digestibility of the 10- and 18-minute samples was slightly higher than the 12- or 15-minute FTH samples. Urea, FTH, BM and 87:12.5, 75:25, and 50:50 combinations of FTH:BM were evaluated in two calf growth studies. The most efficiently utilized protein supplement was 100% BM (P $<$.05). No differences (P =.30) in protein efficiency were observed among the supplements containing various combinations of FTH:BM. All FTH:BM combinations yielded higher protein efficiencies (P $<$.05) than the 100% FTH supplement.
Subject Area
Livestock
Recommended Citation
Blasi, Dale Anthony, "Escape protein supplementation for lactating beef cows and growing calves" (1989). ETD collection for University of Nebraska-Lincoln. AAI9019555.
https://digitalcommons.unl.edu/dissertations/AAI9019555