Effects of postweaning diet on age and weight at puberty and milk production of heifers

• Published in: Journal of animal science Vol. 73; no. 1
• Main Authors: Marston, T.T. (Hubbard Milling Co., Mankato, MN.), Lusby, K.S, Wettemann, R.P
• Format: Journal Article
• Language: English
• Published: 01.01.1995
• Subjects: AGE; ALIMENT CONCENTRE POUR ANIMAUX; BOVIN DE BOUCHERIE; COMPLEMENT ALIMENTAIRE; CONDICION CORPORAL; EDAD; ENGORDE; ENGRAISSEMENT; ETAT CORPOREL; FEMELLE; FERTILIDAD; FERTILITE; GAIN DE POIDS; GANADO DE CARNE; GANANCIA DE PESO; GENISSE; HEMBRA; HIVER; INVIERNO; MADUREZ SEXUAL; MATURITE SEXUELLE; NOVILLA; OKLAHOMA; PARTO; PARTURITION; PERFORMANCE DE REPRODUCTION; PESO; PIENSOS CONCENTRADOS; POIDS; PROTEINA BRUTA; PROTEINE BRUTE; RENDEMENT LAITIER; RENDIMIENTO LECHERO; REPRODUCTIVIDAD; RESIDU DE RECOLTE; RESIDUOS DE COSECHAS; SOJA; SUPLEMENTOS; TORTAS DE SOJA; TOURTEAU DE SOJA; VACA; VACHE
• ISSN: 0021-8812; 1525-3163

One hundred 7-mo-old spring-born beef heifers (215 kg) were used to evaluate effects of level of supplementation and short-term concentrate feeding on age and weight at puberty and milk production. In each of two winters, heifers were individually fed 0.9 kg/d of a 40% CP supplement (SBM) or 1.8 or 2.7 kg/d of a 20% CP supplement (LOW-20 or HIGH-20, respectively) while grazing dormant native pastures or 0.9 kg/d of SBM until February, and then fed a high-concentrate diet (NEg = 1.31 Mcal/kg) in drylot to weigh the same as HIGH-20 heifers on May 1, the beginning of the breeding season. Weights on May 1 were similar for HIGH-20 and DRYLOT heifers (320 and 314 kg, respectively) and were heavier (P 0.01) than those of LOW-20 heifers (289 kg), which were heavier (P 0.01) than SBM-fed heifers (278 kg). Pubertal weight was similar for SBM, LOW-20, and DRYLOT (290, 296, and 297kg, respectively) and heaviest for HIGH-20 heifers (P 0.01, 325 kg). DRYLOT heifers reached puberty at 29 d younger (P 0.05) than heifers on the other treatments. Percentage of heifers puberal on May 1 were 0, 9, 13, and 72 for SBM, LOW-20, HIGH-20, and DRYLOT heifers, respectively. Pregnancy rates were significantly lower for SBM (67%) than for LOW-20, HIGH-20, and DRYLOT (94, 94, and 86%, respectively). Milk production after first parturition was similar for all treatments. Age and weight at puberty may be altered by short-term feeding of high-concentrate diets. The amount of supplemental energy may affect pregnancy rates even though body weight and condition score are not affected