Increased postweaning gain of beef heifers enhances fertility and milk production.

Four hundred fifty-two (452) weanling heifer calves (192 +/- 23 kg) were used to determine the effect of postweaning weight gain on subsequent reproductive performance and lactation. Heifers grazed stockpiled tall fescue pastures and were fed a high (H) or low (L) amount of ground corn supplement (3.68 and 2.99 kg/[animal.d], respectively) during a postweaning treatment period of 136 d. Postweaning gain of heifers receiving L and H was .43 and .62 kg/d, respectively. These treatments resulted in a range of postweaning gain from .07 to 1.17 kg/d. Heifers receiving H were 26 kg heavier (P < .01), had .15 cm more fat thickness (P < .01), 5% greater pelvic area (P < .01), and tended (P = .08) to have greater hip height than heifers receiving L at yearling. More heifers in the H group were pubertal before the start of the breeding season (70.9 vs 61.3%) (P < .05). No significant differences were found in pregnancy rate or first-service calving rate between treatment groups. Mean milk production was 10% greater for H- than for L-fed heifers (P < .01) and resulted in heavier calves at 54, 104, and 153 d of age (P < .05). Regression analysis revealed that as weaning weight and postweaning gain increased, so did the probability for reaching puberty before the breeding season. Increasing weaning weight also increased the probability of calving to the first AI service. As heifer weaning weight and postweaning gain increased, subsequent milk production also increased. Increasing postweaning weight gain of lightweight heifers from .07 to 1.17 kg/d increased both reproductive and lactation performance.

[1]  J. Hodges,et al.  Effects of winter and summer energy levels on heifer growth and reproductive performance. , 1980, Journal of animal science.

[2]  R. M. Kay,et al.  The effects of rapid rearing and early calving on the subsequent performance of dairy heifers , 1979 .

[3]  R. Short,et al.  Relationships among Weight Gains, Age at Puberty and Reproductive Performance in Heifers , 1971 .

[4]  J. Paterson,et al.  Performance, forage utilization, and ergovaline consumption by beef cows grazing endophyte fungus-infected tall fescue, endophyte fungus-free tall fescue, or orchardgrass pastures. , 1992, Journal of animal science.

[5]  R. Short,et al.  Pregnancy rates of beef heifers bred either on puberal or third estrus. , 1987, Journal of animal science.

[6]  G. Fahey,et al.  Effects of creep feeding and monensin on reproductive performance and lactation of beef heifers. , 1982, Journal of animal science.

[7]  Rice Le,et al.  Factors affecting dystocia in beef heifers. , 1972 .

[8]  J. Lesmeister,et al.  Date of First Calving in Beef Cows and Subsequent Calf Production , 1973 .

[9]  J. Huber,et al.  Influence of nutrition of mammary development in pre- and postpubertal heifers. , 1982, Journal of dairy science.

[10]  C. Kasson,et al.  Puberty in crossbred and straightbred beef heifers on two levels of feed. , 1969 .

[11]  W. Hohenboken,et al.  Prediction of fertility from calfhood traits of Angus and Simmental heifers. , 1992, Journal of animal science.

[12]  R. Schalles,et al.  Relationship of milk production, milk expected progeny difference, and calf weaning weight in angus and simmental cow-calf pairs. , 1992, Journal of animal science.

[13]  K. Odde.  A review of synchronization of estrus in postpartum cattle. , 1990, Journal of animal science.

[14]  D. Faulkner,et al.  Norgestomet implants synchronize estrus and enhance fertility in beef heifers subsequent to a timed artificial insemination. , 1993, Journal of animal science.

[15]  J. Oltjen,et al.  Carcass composition in mature Hereford cows: estimation and effect on daily metabolizable energy requirement during winter. , 1988, Journal of animal science.

[16]  R. Alenda,et al.  Creep Feed as a Factor Influencing Performance of Cows and Calves , 1981 .

[17]  G. F. Sargent,et al.  Changes in porcine, ovine, bovine and equine blood progesterone concentrations between collection and centrifugation , 1983 .

[18]  D. Kesler,et al.  Quantification of Steroids via a Polymer Linked Second Antibody Enzyme Immunoassay System: Methods of Linking Anti-Rabbit IgG to Poly(styrene) , 1990 .

[19]  D. Notter,et al.  Techniques for estimation of milk yield in beef cows and relationships of milk yield to calf weight gain and postpartum reproduction. , 1990, Journal of animal science.

[20]  R. Harrison,et al.  A quantitative analysis of mammary glands of dairy heifers reared at different rates of live weight gain , 1983, Journal of Dairy Research.

[21]  R. Schalles,et al.  Effect of growth rate through 30 months on reproductive performance of beef heifers. , 1980, Journal of animal science.

[22]  S. Roberts,et al.  Reproductive performance and profitability of heifers fed to weigh 272 or 318 kg at the start of the first breeding season. , 1985, Journal of animal science.

[23]  C. Ferrell,et al.  Effects of postweaning rate of gain on onset of puberty and productive performance of heifers of different breeds. , 1982, Journal of animal science.

[24]  R. Lemenager,et al.  Estimation of net energy requirements (NEm and NE delta) of lactating beef cows. , 1992, Journal of animal science.

[25]  R. Sacco,et al.  Production characters of primiparous females of a five-breed diallel. , 1987, Journal of animal science.

[26]  A. Parkhurst,et al.  Relationships of pelvic structure, body measurements, pelvic area and calving difficulty. , 1988, Journal of animal science.

[27]  B. Freking,et al.  Interrelationships of heifer milk production and other biological traits with production efficiency to weaning. , 1992, Journal of animal science.

[28]  R. Totusek,et al.  Relation of Estimation Method, Sampling Interval and Milk Composition to Milk Yield of Beef Cows and Calf Gain , 1973 .

[29]  K. Sejrsen.  Mammary Development and Milk Yield in Relation to Growth Rate in Dairy and Dual-purpose Heifers , 1978 .

[30]  E. W. Swanson,et al.  Effect of Rapid Growth with Fattening of Dairy Heifers on Their Lactational Ability , 1960 .