Mangwe Mancoba, Bryant Racheal, Gregorini Pablo
Faculty of Agriculture and Life Sciences, Lincoln University, P.O. Box 7647 Canterbury, New Zealand.
Animals (Basel). 2020 Jan 19;10(1):169. doi: 10.3390/ani10010169.
The goals of the current study were to investigate the effects of including chicory ( L.) into the traditional feeding regime of ryegrass/white clover ( L./ L.), and time of its allocation on milk production, rumen fermentation, and FA composition of milk and rumen digesta of dairy cows. Nine groups of four cows were allocated one of three replicated feeding regimes: (1) ryegrass/white clover only (RGWC), (2) ryegrass/white clover + morning allocation of chicory (CHAM), and (3) ryegrass/white clover + afternoon allocation of chicory (CHPM). One cow per group had a rumen cannulae fitted. Treatment did not affect total grazing time or estimated dry matter intake, but cows ruminated more when fed RGWC than chicory. Allocating chicory in the afternoon elevated milk production compared with RGWC and CHAM. Milk from cows grazing chicory contained greater concentrations of polyunsaturated FA (PUFA) such as C18:3 c9, 12, 15 and C18:2 c9, 12 than those on RGWC. As with milk, rumen digesta concentration of PUFA increased when cows grazed on chicory rather than RGWC, which corresponded with lower concentrations of intermediate vaccenic and biohydrogenation end-product stearic acid for cows grazing on chicory. Mean ruminal pH was lower for cows offered chicory than those on RGWC, reflecting greater rumen concentrations of volatile fatty acids (VFA) for cows fed chicory. Allocating chicory during the afternoon is a useful strategy that can translate to improved milk production. The lower rumen pH, lower concentration of vaccenic and stearic acids, and elevated concentration of PUFA in the rumen of cows fed chicory suggest reduced biohydrogenation and may explain the elevated concentration of PUFA in the milk of cows fed chicory compared with those fed RGWC.
本研究的目的是调查将菊苣（菊苣属）纳入黑麦草/白三叶（黑麦草属/三叶草属）传统饲养方式的效果，以及其分配时间对奶牛产奶量、瘤胃发酵以及牛奶和瘤胃消化物脂肪酸组成的影响。将9组，每组4头奶牛分配到三种重复饲养方式之一：（1）仅黑麦草/白三叶（RGWC），（2）黑麦草/白三叶+上午分配菊苣（CHAM），以及（3）黑麦草/白三叶+下午分配菊苣（CHPM）。每组有一头奶牛安装了瘤胃瘘管。处理对总放牧时间或估计干物质摄入量没有影响，但与饲喂菊苣相比，饲喂RGWC时奶牛反刍更多。与RGWC和CHAM相比，下午分配菊苣提高了产奶量。放牧菊苣的奶牛所产牛奶中多不饱和脂肪酸（PUFA）如C18:3 c9,12,15和C18:2 c9,12的浓度高于饲喂RGWC的奶牛。与牛奶一样，当奶牛放牧菊苣而非RGWC时，瘤胃消化物中PUFA的浓度增加，这与放牧菊苣的奶牛中间型共轭亚油酸和生物氢化终产物硬脂酸的浓度较低相对应。饲喂菊苣的奶牛瘤胃平均pH低于饲喂RGWC的奶牛，这反映出饲喂菊苣的奶牛瘤胃中挥发性脂肪酸（VFA）浓度更高。下午分配菊苣是一种有用的策略，可以提高产奶量。饲喂菊苣的奶牛瘤胃pH较低、共轭亚油酸和硬脂酸浓度较低以及瘤胃中PUFA浓度升高表明生物氢化减少，这可能解释了与饲喂RGWC的奶牛相比，饲喂菊苣奶牛的牛奶中PUFA浓度升高的原因。
