Effects of body composition, pre- and postpartum energy level and early weaning on reproductive performance of beef cows and preweaning calf gain

• Published in: Journal of animal science Vol. 68; no. 5; p. 1438
• Main Authors: Houghton, P.L. (Kansas State University, Colby), Lemenager, R.P, Horstman, L.A, Hendrix, K.S, Moss, G.E
• Format: Journal Article
• Language: English
• Published: United States 01.05.1990
• Subjects: Anestrus; ANIMAL DEVELOPMENTAL STAGES; Animals; Animals, Suckling - growth & development; BEEF CATTLE; Body Composition; BOVIN DE BOUCHERIE; CALVES; CARCASS COMPOSITION; Cattle - growth & development; Cattle - physiology; COMPOSICION DE LA CANAL; COMPOSITION DE LA CARCASSE; COWS; DESTETE; Energy Intake; ETAPAS DEL DESARROLLO ANIMAL; FECONDITE; FECUNDIDAD; FECUNDITY; FEED INTAKE; Female; Fertilization; GAIN DE POIDS; GANADO DE CARNE; GANANCIA DE PESO; GESTACION; GESTATION; INGESTION DE PIENSO; Labor, Obstetric - physiology; Ovulation; POSTPARTUM INTERVAL; PREGNANCY; PRISE ALIMENTAIRE (ANIMAUX); PUERPERIO; PUERPERIUM; Random Allocation; Reproduction; SEVRAGE; STADE DE DEVELOPPEMENT ANIMAL; TERNERO; VACA; VACHE; VEAU; WEANING; WEIGHT GAIN
• DOI: 10.2527/1990.6851438x
• ISSN: 0021-8812

Mature Charolais x Angus rotational cross cows were adjusted to moderate body condition by d 190 of gestation then randomly blocked to a maintenance (ME) or low-energy (LE) diet. At parturition, the 128 cows were randomly allotted within prepartum (PRP) diet to a high-energy (HE) or LE diet. At d 30 postpartum (PP), cows were randomly blocked to two treatments in which calves were weaned early (EW) or normally (NW) at 7 mo of age. Cows receiving a LE PRP diet had lighter calves at birth (34.7 vs 39.0 kg) and 105 d (127.9 vs 144.6 kg). Prepartum and PP energy interacted to affect postpartum anestrous interval (PPI, d) and cycling activity (%), respectively (LE-LE = 72.6, 33.3; LE-HE = 54.3, 56.3; ME-LE = 65.7, 52.9; ME-HE = 68.4, 54.3). High PP energy averaged over PRP diet increased (P less than .10) pregnancy rate by 22.7% and 105-d calf weight by 15.1 kg. Early weaning reduced PPI by 24.3 d (P less than .01) and first service conception rate by 21.7% (P less than .10). Cycling activity within 60 d PP was affected (P less than .01) by PRP diet and suckling status (LE-EW = 62.5, LE-NW = 26.7, ME-EW = 88.9, ME-NW = 13.3%). Thin cows had a longer PPI but had a higher first service conception rate than moderate and fleshy cows. Higher pregnancy rates were observed in cows approaching or maintaining average body condition from parturition to conception than for cows moving away from moderate body condition. Results suggest that fleshy and thin cows at parturition should be managed to approach moderate body condition before the breeding season to optimize reproductive performance and preweaning calf gain.