[1] SMITH J,SONES K,GRACE D,et al.Beyond milk,meat,and eggs:role of livestock in food and nutrition security[J].Animal Frontiers,2013,3(1):6-13.

[2] 刘长全,韩磊.2020年中国奶业经济形势回顾及2021年展望[J].中国畜牧杂志,2021,57(3):212-216. LIU C Q,HAN L.Review of economic situation of China dairy industry in 2020 and outlook in 2021[J].Chinese Journal of Animal Science,2021,57(3):212-216.(in Chinese)
[3] 张淑二,翟向玮,尹旭升,等.月龄对德系西门塔尔种公牛精液品质及产能的影响[J].中国草食动物科学,2014,34(3):33-34. ZHANG S E,ZHAO X W,YIN X S,et al.Effect of month age on semen quality and productivity of german simmental bulls[J].China Herbivore Science,2014,34(3):33-34.(in Chinese)
[4] 杜超,甄玉国,KERTZ A F,等.不同物理形态开食料对犊牛生长发育、瘤胃发酵及血液指标的影响[J].动物营养学报,2017,29(6):2153-2161. DU C,ZHEN Y G,KERTZ A F,et al.Effects of starters in different physical forms on growth and development,rumen fermentation and blood parameters of dairy calves[J].Chinese Journal of Animal Nutrition,2017,29(6):2153-2161.(in Chinese)
[5] EBNALI A,KHORVASH M,GHORBANI G R,et al.Effects of forage offering method on performance,rumen fermentation,nutrient digestibility and nutritional behaviour in Holstein dairy calves[J].Journal of Animal Physiology and Animal Nutrition,2016,100(5):820-827.

[6] MOEINI H,MAHDAVI A H,RIASI A,et al.Effects of physical form of starter and forage provision to young calves on blood metabolites,liver composition and intestinal morphology[J].Journal of Animal Physiology and Animal Nutrition,2016,101(4):755-766.
[7] FRANKLIN S T,AMARAL-PHILLIPS D M,JACKSON J A,et al.Health and performance of Holstein calves that suckled or were hand-fed colostrum and were fed one of three physical forms of starter[J].Journal of Dairy Science,2003,86(6):2145-2153.

[8] 阿米娜木·司马义.口感化和颗粒化开食料对荷斯坦公犊牛生长性能及胃肠道发育的影响[D].硕士学位论文.乌鲁木齐:新疆农业大学,2014. AMINAMU S M Y.Effects of texturized and pelleted starter on growth characteristics and gastrointestinal development in Holstein male calves[D].Master's Thesis.Urumchi:Xinjiang Agricultural University,2014.(in Chinese)
[9] BATEMAN Ⅱ T M,HILL T M,ALDRICH J M,et al.Effects of corn processing,particle size,and diet form on performance of calves in bedded pens[J].Journal of Dairy Science,2009,92(2):782-789.

[10] CASTELL L,BACH A,ARAUJO G,et al.Effect of different forage sources on performance and feeding behavior of Holstein calves[J].Journal of Dairy Science,2012,95(1):286-293.

[11] KHAN M A,WEARY D M,VEIRA D M,et al.Postweaning performance of heifers fed starter with and without hay during the milk-feeding period[J].Journal of Dairy Science,2012,95(7):3970-3976.

[12] 吴兆海.不同牧草补饲模式对犊牛生长及胃肠道发育的影响[D].硕士学位论文.晋中:山西农业大学,2014. WU Z H.Effects of different forage supplementary patterns on the growth and gastrointestinal development of Holstein calves[D].Master's Thesis.Jinzhong:Shanxi Agricultural University,2014.(in Chinese)
[13] ARAGONA K M,DENNIS T S,SUAREZ-MENA F X,et al.Effect of increasing the amount of hay fed on Holstein calf performance and digestibility from 2 to 4 months of age[J].Journal of Dairy Science,2020,104(2):1620-1629.
[14] 闫晓刚.酵母培养物和颗粒精料对荷斯坦犊牛生长发育的影响[D].硕士学位论文.长春:吉林农业大学,2005. YAN X G.Effects of yeast culture and granular concentrate on growth and development of Holstein calves[D].Master's Thesis.Changchun:Jilin Agricultural University,2005.(in Chinese)
[15] LESMEISTER K E,HEINRICHS A J.Effects of corn processing on growth characteristics,rumen development,and rumen parameters in neonatal dairy calves[J].Journal of Dairy Science,2004,87(10):3439-3450.

[16] 刁其玉.犊牛营养生理与高效健康培育[M].北京:中国农业出版社,2019. DIAO Q Y.Nutritional physiology and efficient healthy breeding of calves[M].Beijing:China Agriculture Press,2019.
[17] KINCAID R L.Alternate methods of feeding alfalfa to calves[J].Journal of Dairy Science,1980,63(1):91-94.

[18] VAN DE STROET D L,DÍAZ J A C,STALDER K J,et al.Association of calf growth traits with production characteristics in dairy cattle[J].Journal of Dairy Science,2016,99(10):8347-8355.

[19] CHELIKANI P K,AMBROSE D J,KEISLER D H,et al.Effects of dietary energy and protein density on plasma concentrations of leptin and metabolic hormones in dairy heifers[J].Journal of Dairy Science,2009,92(4):1430-1441.

[20] STANLEY C C,WILLIAMS C C,JENNY B F,et al.Effects of feeding milk replacer once versus twice daily on glucose metabolism in Holstein and Jersey calves[J].Journal of Dairy Science,2002,85(9):2335-2343.

[21] BORG B S,LIBAL G M,WAHLSTROM R C,et al.Tryptophan and threonine requirements of young pigs and their effects on serum calcium,phosphorus and zinc concentrations[J].Journal of Animal Science,1987,64(4):1070-1078.

[22] 罗洪明.饲粮不同蛋白水平对早期断奶仔猪生产性能、血液生化指标及免疫机能的影响[D].硕士学位论文.成都:四川农业大学,2005. LUO H M.Effects of different dietary protein levels on growing performance,blood biochemical parameters and immune function of early-weaned piglets[D].Master's Thesis.Chengdu:Sichuan Agricultural University,2005.(in Chinese)
[23] 李天星.现代临床免疫学检验[M].北京:军事医学科学出版社,2001. LI T X.Modern clinical immunological test[M].Beijing:Military Medical Science Press,2001.(in Chinese)
[24] XU C,WENSING T,BEYNEN A C.Effects of high calcium intake on fat digestion and bile acid excretion in feces of veal calves[J].Journal of Dairy Science,1998,81(8):2173-2177.

[25] 仁瑞清.不同饲喂模式对犊牛生长以及胃肠道发育的影响[D].硕士学位论文.保定:河北农业大学,2012. REN R Q.Effects of different feeding patterns on growth and digestive tract development in preweaning calves[D].Master's Thesis.Baoding:Hebei Agricultural University,2012.(in Chinese)
[26] 崔祥.日粮能量水平对4-6月龄犊牛生长、消化代谢及瘤胃内环境的影响[D].硕士学位论文.北京:中国农业科学院,2014. CUI X.Effect and mechanism of different energy level on growth,digestion and metabolism,ruminal environment in heifers aged 4 to 6 months[D].Master's Thesis.Beijing:Chinese Academy of Agricultural Sciences,2014.(in Chinese)