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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #121783
Title: PREPARTUM SUPPLEMENTATION WITH PROTEIN OR FAT AND PROTEIN FOR GRAZING COWS IN THREE SEASONS OF CALVING

Author
item Grings, Elaine
item Short, Robert
item Blummel, Michael
item Macneil, Michael
item BELLOWS, ROBERT - USDA-ARS RETIRED

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2001
Publication Date: 6/1/2001
Citation: GRINGS, E.E., SHORT, R., BLUMMEL, M.R., MACNEIL, M.D., BELLOWS, R.A. PREPARTUM SUPPLEMENTATION WITH PROTEIN OR FAT AND PROTEIN FOR GRAZING COWS IN THREE SEASONS OF CALVING. JOURNAL OF ANIMAL SCIENCE SUPPLEMENT. 2001. v. 79(Suppl. 2). p. 141.

Interpretive Summary: A 2-yr study was conducted to evaluate prepartum supplementation of cows (n = 177) grazing rangeland with a combination of safflower seed and meal (high fat, HF: 21.7% CP, 14.8% ether extract, EE) compared to safflower meal and barley (low fat, LF: 22.5% CP, 2.6% EE) on cow performance. Interactions with calving date and cow age (CA) were also evaluated. Each year, 30 cows (15 three-yr-olds and 15 five-yr-olds or older) from each of three seasons of calving (SC; February, April, or June) were assigned to supplementation type (ST). Cows were assigned to one of two pastures per SC and supplements were group fed for 49 d. Cows were then moved to drylot and fed sudangrass hay plus supplements until calving (average = 22 d). While effects of SC and CA were pronounced for performance measures, effects of ST were limited and were only found in interactions. Changes in BW during the prepartum grazing period were affected by SC (P < 0.01), a year by CA interaction (P < 0.05), and an interaction among SC, ST, year, and CA (P < 0.05). In the April calving group, proportion of 3-yr-olds exhibiting estrous cycles at the beginning of breeding was 0.46 compared with 0.92 in the older cows, but there was no effect of CA in the February or June groups (SC by CA interaction, P < 0.05). Pregnancy rates exhibited a SC by ST by CA interaction (P < 0.05). Three-year-old cows calving in February and 5- yr-old cows calving in April receiving HF had greater pregnancy rates than cows fed LF; the opposite effect was found for 3-yr-olds calving in April. There was no effect of ST on pregnancy rates of cows calving in June. Varying conditions associated with SC affected cow performance and response to supplementation.

Technical Abstract: A 2-yr study was conducted to evaluate prepartum supplementation of cows (n = 177) grazing rangeland with a combination of safflower seed and meal (high fat, HF: 21.7% CP, 14.8% ether extract, EE) compared to safflower meal and barley (low fat, LF: 22.5% CP, 2.6% EE) on cow performance. Interactions with calving date and cow age (CA) were also evaluated. Each year, 30 cows (15 three-yr-olds and 15 five-yr-olds or older) from each of three seasons of calving (SC; February, April, or June) were assigned to supplementation type (ST). Cows were assigned to one of two pastures per SC and supplements were group fed for 49 d. Cows were then moved to drylot and fed sudangrass hay plus supplements until calving (average = 22 d). While effects of SC and CA were pronounced for performance measures, effects of ST were limited and were only found in interactions. Changes in BW during the prepartum grazing period were affected by SC (P < 0.01), a year by CA interaction (P < 0.05), and an interaction among SC, ST, year, and CA (P < 0.05). In the April calving group, proportion of 3-yr-olds exhibiting estrous cycles at the beginning of breeding was 0.46 compared with 0.92 in the older cows, but there was no effect of CA in the February or June groups (SC by CA interaction, P < 0.05). Pregnancy rates exhibited a SC by ST by CA interaction (P < 0.05). Three-year-old cows calving in February and 5- yr-old cows calving in April receiving HF had greater pregnancy rates than cows fed LF; the opposite effect was found for 3-yr-olds calving in April. There was no effect of ST on pregnancy rates of cows calving in June. Varying conditions associated with SC affected cow performance and response to supplementation.