Reproductive efficiency of range beef cows fed differing sources of protein during gestation and differing quantities of ruminally undegradable protein prior to breeding
Year: 1991
Type: dissertation
Abstract: Three experiments utilizing 165 crossbred multiparous beef cows grazing native spring range were conducted to determine the effects of pre-and postpartum protein supplementation on nutrient status, milk production, and subsequent calf and reproductive performance.In experiment one, two and three, pregnant cows were fed 20% crude protein supplements formulated with alfalfa or canola every other day at 1.82 kg/hd from 12-5-91 until calving.In the third experiment using three-year-old cows, a third treatment was added, which was designed to serve as an energy control consisting only of 1.6 kg beet pulp/hd fed on alternate days.After parturition cows in all three experiments were fed one of two iso-nitrogenous and iso-energetic supplements.One experimental supplement designated ruminally undegraded (UD) was formulated to contain .245kg of ruminally degradable and .245kg of ruminally undegradable protein daily.The second supplement designated ruminally degraded (RD) was formulated to supply .371 kg ruminally degradable protein and .119 kg undegradable protein daily.These supplements were fed on alternate days at 1.82 kg/hd until the breeding season.Experiment 1 consisted of late calving cows that grazed spring range and were individually fed supplement postpartum.Experiment 2, composed of early calving cows, and experiment 3, consisting of three year old cows moved from the Montana State University Livestock Center after calving, were group fed supplement on alternate days and daily fed one-half ration of medium quality hay (10.5% CP) .In Exp. 1 BUN concentration was 1.8 mg/dl higher (P < .01) on day 53 postpartum for UD fed cows.Milk production did not differ due to prepartum or postpartum treatments.Prepartum weight gain was greater for canola-fed cows (P < .001)compared to alfalfa.Group-fed cows experienced less postpartum weight loss prior to the breeding season when fed UD supplement (P < .001).Preweaning calf gain, cow fecal output and fall pregnancy rates were unaffected by pre-and postcalving supplementation.Three year old cows fed beet pulp prepartum were less (P < .001)frequently serviced in the first 21 days of the breeding season (54.5%) than the canola-or alfalfa-fed cows (95% and 96% respectively).Overall, pre-and postpartum protein supplementation affected cow weight change and allowed for high reproductive performance between cows fed either RD or UD protein supplement postpartum.
Author: Dhuyvetter, Daniel Vincent
Institution: Montana State University
Language: English
Subfield: Animal Science and Zoology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
Funder: North Dakota State University
OpenAlex ID: W114383102