5Martin J L,Vonnahme K A,Adams D C,Lardy G P,Funston R N.Effects of dam nutrition on growth and reproductive performance of heifer calves[].The Journal of Animal Ecology.2006
4C[anton D C, Zmmerman D R. Symposium on pasture methods for maximum producti on in beef cattle: Protein and energy require- ments for female beef cattle[J]. J Anita Sei, 1970, 30: 122-132.
5DelCurto T, Coehran R C, Corah L R, et al. Johnson. supplemen- tation of dormant tallgrass-prairie forage: Ⅱ. performance and forage utilization charaeteristics in grazing beef caltle receiving supplements of different protein concentrations [J]. J Anita Sci, 1990, 68: 532-542.
6Marston T T, Lusby K S, Wettemann R P, et al. Effects of feed- ing energy or protein supplements before or after calving on per- fomlance of spring-calving cows grazing native range [J]. J Anita Sci, 1995, 73: 657-664.
7Perry R C, Corah L R, Cochran R C, et al. Influence of dietary energy on follicular development, serum gonadotropins, and first postpartum ovulation in suckled beef cows[J]. J Anim Sci, 1991, 69: 3762-3773.
8莫放.养牛生产学(2版)[M].北京:中国农业大学出版社,2010.
9Bourdon R M, Brinks J S. Genetic, environmental and phenotyp- ic relationships among gestation 1 ength, birth weight, growth traits and age at first calving in beef cattle[J]. J Anim Sci, 1982, 55: 543-553.
10Spitzer J C, Morrison D G, Wettemann R P, et ai. Reproductive responses and calf birth and weaning weights as affected by body condition at parturition and postpartum weight gain in primi- parous beef cows[J]. J Anim Sci, 1995, 73: 1251-1257.