EFFECTS OF FEEDING HIGH LINOLEATE SAFFLOWER SEEDS PREPARTUM ON LEPTIN CONCENTRATION, WEANING, AND RE-BREEDING PERFORMANCE OF BEEF HEIFERS

Authors: Geary, Thomas; Grings, Elaine; Macneil, Michael; KEISLER, D - UNIV OF MISSOURI

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2002
Publication Date: 6/1/2002
Citation: GEARY, T.W., GRINGS, E.E., MACNEIL, M.D., KEISLER, D.H. EFFECTS OF FEEDING HIGH LINOLEATE SAFFLOWER SEEDS PREPARTUM ON LEPTIN CONCENTRATION, WEANING, AND RE-BREEDING PERFORMANCE OF BEEF HEIFERS. JOURNAL OF ANIMAL SCIENCE SUPPLEMENT. 2002. v. 80(Suppl. 2). p. 131-132.

Interpretive Summary: Our objective was to identify potential mechanisms by which prepartum diets high in linoleic acid increase calf weaning weight and heifer rebreeding performance. Thirty-six Angus and Hereford-Angus heifers that conceived on the same day to one sire were stratified by weight (436.1 ± 27.8 kg) and body condition score (BCS, 4.4 ± 0.7) and within strata assigned to receive a prepartum diet high in linoleic acid (S) or control (C) diet. Diets were isocaloric and isonitrogenous. Heifers were fed in pens of six from d -56 until calving. At calving, heifers were housed together and fed the same diet for the duration of the study. Blood samples were collected on d -56, -42, -28, -14, -10 to d 3, and twice weekly from d 0 (calving) to d 172 postpartum. Hip height, BW, BCS, and ultrasound fat depth were measured every 28 d. Heifers were exposed to one bull from d 126 to 175 and examined for pregnancy by ultrasound on d 172 and 209. Weight and BCS at calving did not differ (P > 0.10) between heifers fed S (455 kg, 5.8) or C (445 kg, 5.8). Calf birth weight and dystocia did not differ (P > 0.10), but calf vigor was greater (P < 0.05) in calves born to heifers receiving S. Weight, BCS, fat depth over the back and rump, hip height:weight, and serum leptin concentrations were not affected (P > 0.10) by treatment or treatment by day interaction. Pregnancy rate, postpartum interval, and interval from calving to conception did not differ (P > 0.10) between heifers fed S or C. Calf weaning weights adjusted for age and sex were similar between heifers fed S (241 ± 18 kg) vs C (232 ± 32 kg). We were unable to identify differences between heifers fed S vs C.

Technical Abstract: Our objective was to identify potential mechanisms by which prepartum diets high in linoleic acid increase calf weaning weight and heifer rebreeding performance. Thirty-six Angus and Hereford-Angus heifers that conceived on the same day to one sire were stratified by weight (436.1 ± 27.8 kg) and body condition score (BCS, 4.4 ± 0.7) and within strata assigned to receive a prepartum diet high in linoleic acid (S) or control (C) diet. Diets were isocaloric and isonitrogenous. Heifers were fed in pens of six from d -56 until calving. At calving, heifers were housed together and fed the same diet for the duration of the study. Blood samples were collected on d -56, -42, -28, -14, -10 to d 3, and twice weekly from d 0 (calving) to d 172 postpartum. Hip height, BW, BCS, and ultrasound fat depth were measured every 28 d. Heifers were exposed to one bull from d 126 to 175 and examined for pregnancy by ultrasound on d 172 and 209. Weight and BCS at calving did not differ (P > 0.10) between heifers fed S (455 kg, 5.8) or C (445 kg, 5.8). Calf birth weight and dystocia did not differ (P > 0.10), but calf vigor was greater (P < 0.05) in calves born to heifers receiving S. Weight, BCS, fat depth over the back and rump, hip height:weight, and serum leptin concentrations were not affected (P > 0.10) by treatment or treatment by day interaction. Pregnancy rate, postpartum interval, and interval from calving to conception did not differ (P > 0.10) between heifers fed S or C. Calf weaning weights adjusted for age and sex were similar between heifers fed S (241 ± 18 kg) vs C (232 ± 32 kg). We were unable to identify differences between heifers fed S vs C.