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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Feeding Supplemental Fat During Gestation on Reproduction in First-Calf Beef Heifers

Authors
item Bellows, Robert
item Simms, D - CONSOLIDATED NUTRITION
item Grings, Elaine
item Phelps, D - MAES
item Bellows, Susan
item Bellows, N - MAES
item Short, Robert
item Funston, R - MONT. EXTENSION SERVICE
item Geary, Thomas

Submitted to: Research Update for Fort Keogh Livestock and Range Research Laboratory
Publication Type: Other
Publication Acceptance Date: October 1, 1999
Publication Date: October 1, 1999
Citation: BELLOWS, R.A., SIMMS, D.D., GRINGS, E.E., PHELPS, D.A., BELLOWS, S.E., BELLOWS, N.R., SHORT, R., FUNSTON, R.N., GEARY, T.W. EFFECTS OF FEEDING SUPPLEMENTAL FAT DURING GESTATION ON REPRODUCTION IN FIRST-CALF BEEF HEIFERS. RESEARCH UPDATE FOR FORT KEOGH LIVESTOCK AND RANGE RESEARCH LABORATORY. 1999. p. D11.1-2.

Interpretive Summary: Primiparous, crossbred beef heifers (n = 149) calving in three calving seasons (February, April, or June) were assigned randomly to one of four gestation diets: Control or added safflower seeds, soybeans, or sunflower seeds. Oil seeds were processed through a roller mill to crack hulls in approximately 90% of seeds but without oil loss. Diets were isocaloric-isonitrogenous and contained 2.0, 4.2, 3.3, or 4.5% fat, respectively. Diets were group fed in dry lot and were fed for an average of 65.3 d precalving. Heifer weights and body condition scores (1-10) were obtained throughout the study; estrous cycling activity was based on progesterone content of blood samples obtained at begin breeding; pregnancy was determined by ultrasound at 60-90 days following 35-37 d estrous-synchronized breeding seasons. Calf data included birth weight, calving ease, sex, and weaning weight. Data were analyzed by SAS-GLM within and pooled over calving seasons. Effects of fat supplementation on dam weight or condition scores throughout the study were nonsignificant as were effects on birth weight, calving ease, and dam estrous cyclicity at begin breeding. Heifers from fat supplemented groups had greater pregnancy rates (P<.05) and calf weaning weights (P=.09): Control, 79%, 182.4 kg; safflower seeds, 94%, 193.6 kg; soybeans, 90%, 197.7 kg; sunflower seeds, 91%, 196.8 kg (mean values pooled over calving seasons). We conclude fat supplementation of the gestation diet in primiparous heifers resulted in positive increases in dam pregnancy rates and tended to increase calf weaning weights.

Technical Abstract: Primiparous, crossbred beef heifers (n = 149) calving in three calving seasons (February, April, or June) were assigned randomly to one of four gestation diets: Control or added safflower seeds, soybeans, or sunflower seeds. Oil seeds were processed through a roller mill to crack hulls in approximately 90% of seeds but without oil loss. Diets were isocaloric-isonitrogenous and contained 2.0, 4.2, 3.3, or 4.5% fat, respectively. Diets were group fed in dry lot and were fed for an average of 65.3 d precalving. Heifer weights and body condition scores (1-10) were obtained throughout the study; estrous cycling activity was based on progesterone content of blood samples obtained at begin breeding; pregnancy was determined by ultrasound at 60-90 days following 35-37 d estrous-synchronized breeding seasons. Calf data included birth weight, calving ease, sex, and weaning weight. Data were analyzed by SAS-GLM within and pooled over calving seasons. Effects of fat supplementation on dam weight or condition scores throughout the study were nonsignificant as were effects on birth weight, calving ease, and dam estrous cyclicity at begin breeding. Heifers from fat supplemented groups had greater pregnancy rates (P<.05) and calf weaning weights (P=.09): Control, 79%, 182.4 kg; safflower seeds, 94%, 193.6 kg; soybeans, 90%, 197.7 kg; sunflower seeds, 91%, 196.8 kg (mean values pooled over calving seasons). We conclude fat supplementation of the gestation diet in primiparous heifers resulted in positive increases in dam pregnancy rates and tended to increase calf weaning weights.

Last Modified: 10/1/2014
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