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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #89960
Title: EFFECTS OF GESTATION EXERCISE

Author
item Bellows, Robert
item Short, Robert
item STAIGMILLER, ROBERT - RETIRED USDA-ARS

Submitted to: Governors Conference on the State of the Livestock Industry
Publication Type: Popular Publication
Publication Acceptance Date: 8/1/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: The study involved 44 primiparous, 2-yr-old heifers and 74 multiparous cows, 3 or 4 yr old, bred to a single Charolais bull. Variables were dam age (heifer, H; or cow, C), restricted (RE) or forced (FE) exercise for the last 90 d precalving, & natural (NP) or induced (IP) parturition. The RE dams were held in drylots; FE dams were on range until d 260 to 267 and walked 3.2 km/d for feed & water. Dams with IP received 10 mg of flu- methazone on d 269 of gestation. Diets for FE & RE dams contained the same hay and grain, but FE dams were fed in amounts projected to give weight changes approximating those of RE dams. All dams were calved in drylots; thereafter, all pairs were maintained together on pasture to the end of the study. Exercise did not affect dystocia score or incidence, increased feed requirement 31%, and gave a 14.8% higher pregnancy rate in the subsequent 45-d breeding season. We hypothesize the increased preg- nancy may have resulted from a feed-indocrine effect related to body weight gain, body composition-metabolic changes, or subsequent higher feed intake. Induced calving shortened gestation length 8 d, reduced calf birth wt 2.5 kg, increased the incidence of retained fetal membranes (RFM) 60.3% estrus 7.6 d, & reduced calf weaning weight 6.9 kg. Body weights & calf birth weights from C exceeded those of H, & more C showed estrus by beginning of the breeding season and had a 20.4-d shorter postpartum interval than H. We conclude that gestation exercise increased feed requirements, had no significant effect on parturition traits, and increased subsequent pregnancy rate; induced calving increased subsequent pregnancy rate; induced calving increased the incidence of RFM, increased the postpartum interval, and decreased subsequent pregnancy rate.

Technical Abstract: The study involved 44 primiparous, 2-yr-old heifers and 74 multiparous cows, 3 or 4 yr old, bred to a single Charolais bull. Variables were dam age (heifer, H; or cow, C), restricted (RE) or forced (FE) exercise for the last 90 d precalving, & natural (NP) or induced (IP) parturition. The RE dams were held in drylots; FE dams were on range until d 260 to 267 and walked 3.2 km/d for feed & water. Dams with IP received 10 mg of flu- methazone on d 269 of gestation. Diets for FE & RE dams contained the same hay and grain, but FE dams were fed in amounts projected to give weight changes approximating those of RE dams. All dams were calved in drylots; thereafter, all pairs were maintained together on pasture to the end of the study. Exercise did not affect dystocia score or incidence, increased feed requirement 31%, and gave a 14.8% higher pregnancy rate in the subsequent 45-d breeding season. We hypothesize the increased preg- nancy may have resulted from a feed-indocrine effect related to body weight gain, body composition-metabolic changes, or subsequent higher feed intake. Induced calving shortened gestation length 8 d, reduced calf birth wt 2.5 kg, increased the incidence of retained fetal membranes (RFM) 60.3% estrus 7.6 d, & reduced calf weaning weight 6.9 kg. Body weights & calf birth weights from C exceeded those of H, & more C showed estrus by beginning of the breeding season and had a 20.4-d shorter postpartum interval than H. We conclude that gestation exercise increased feed requirements, had no significant effect on parturition traits, and increased subsequent pregnancy rate; induced calving increased subsequent pregnancy rate; induced calving increased the incidence of RFM, increased the postpartum interval, and decreased subsequent pregnancy rate.