Beiranvand H, Ghorbani G R, Khorvash M, Nabipour A, Dehghan-Banadaky M, Homayouni A, Kargar S
Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran.
Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran.
J Dairy Sci. 2014;97(4):2270-80. doi: 10.3168/jds.2012-6332. Epub 2014 Feb 6.
The objective of this experiment was to investigate the effects of different levels of alfalfa hay (AH) and sodium propionate (Pro) added to starter diets of Holstein calves on growth performance, rumen fermentation characteristics, and rumen development. Forty-two male Holstein calves (40±2kg of birth weight) were used in a complete randomized design with a 3×2 factorial arrangement of treatments. Dietary treatments were as follows: (1) control = concentrate only; (2) Pro = concentrate with 5% sodium propionate [dry matter (DM) basis]; (3) 5% AH = concentrate + 5% alfalfa hay (DM basis); (4) 5% AH + Pro = concentrate + 5% alfalfa hay + 5% sodium propionate (DM basis); (5) 10% AH = concentrate + 10% alfalfa hay (DM basis); and (6) 10% AH + Pro = concentrate + 10% alfalfa hay + 5% sodium propionate (DM basis). All calves were housed in individual pens bedded with sawdust until 10wk of age. They were given ad libitum access to water and starter throughout the experiment and were fed 2L of milk twice daily. Dry matter intake was recorded daily and body weight weekly. Calves from the control, 10% AH, and 10% AH + Pro treatments were euthanized after wk 10, and rumen wall samples were collected. Feeding of forage was found to increase overall dry matter intake, average daily gain, and final weight; supplementing sodium propionate had no effect on these parameters. Calves consuming forage had lower feed efficiency than those on the Pro diet. Rumen fluid in calves consuming forage had higher pH and greater concentrations of total volatile fatty acids and molar acetate. Morphometric parameters of the rumen wall substantiated the effect of AH supplementation, as plaque formation decreased macroscopically. Overall, the interaction between forage and sodium propionate did not affect calf performance parameters measured at the end of the experiment. Furthermore, inclusion of AH in starter diets positively enhanced the growth performance of male Holstein calves and influenced both the macroscopic and microscopic appearances of the rumen wall. These benefits, however, were small when only sodium propionate was offered.
本试验旨在研究在荷斯坦犊牛起始日粮中添加不同水平的苜蓿干草（AH）和丙酸钠（Pro）对其生长性能、瘤胃发酵特性及瘤胃发育的影响。选用42头雄性荷斯坦犊牛（出生体重40±2kg），采用完全随机设计，处理按3×2析因排列。日粮处理如下：（1）对照 = 仅精料；（2）Pro = 含5%丙酸钠的精料[以干物质（DM）计]；（3）5%AH = 精料 + 5%苜蓿干草（以DM计）；（4）5%AH + Pro = 精料 + 5%苜蓿干草 + 5%丙酸钠（以DM计）；（5）10%AH = 精料 + 10%苜蓿干草（以DM计）；（6）10%AH + Pro = 精料 + 10%苜蓿干草 + 5%丙酸钠（以DM计）。所有犊牛饲养于铺有锯末的单栏中直至10周龄。整个试验期间自由饮水和采食开食料，每天喂给2L牛奶。每天记录干物质采食量，每周称体重。第10周后对对照、10%AH和10%AH + Pro处理组的犊牛实施安乐死，并采集瘤胃壁样本。发现饲喂粗饲料可增加总体干物质采食量、平均日增重和终体重；添加丙酸钠对这些参数无影响。采食粗饲料的犊牛饲料效率低于Pro日粮组犊牛。采食粗饲料的犊牛瘤胃液pH值较高，总挥发性脂肪酸浓度和乙酸摩尔浓度也较高。瘤胃壁的形态学参数证实了添加AH的效果，肉眼可见菌斑形成减少。总体而言，粗饲料和丙酸钠之间的交互作用未影响试验结束时测定的犊牛性能参数。此外，在开食料中添加AH可积极提高雄性荷斯坦犊牛的生长性能，并影响瘤胃壁的宏观和微观外观。然而，仅添加丙酸钠时这些益处较小。
