Manoukian Marley, DelCurto Timothy, Kluth Janessa, Carlisle Tanner, Davis Noah, Nack Makae, Wyffels Samuel, Scheaffer Abe, Van Emon Megan
Department of Animal and Range Sciences, Montana State University, Bozeman, MT 59717, USA.
Northern Agricultural Research Center, Montana State University, Havre, MT 59501, USA.
Animals (Basel). 2021 Oct 20;11(11):3011. doi: 10.3390/ani11113011.
The objectives of this study were to evaluate the effect of differences in protein type and delivery method on rumen dynamics and nutrient digestion. Cows were allotted to rumen degradable protein (RDP) or rumen undegradable protein (RUP) and self-fed (SF) salt-limited pressed blocks or hand-fed (HF) loose supplement, resulting in four dietary treatments. There was a delivery effect ( = 0.04) on neutral detergent fiber (NDF) intake, as the SF animals consumed more NDF than HF animals. The RDP-SF animals had greater NDF digestibility ( = 0.04) and water intake ( = 0.03) than the three other treatments. Supplement intake displayed a protein type effect ( = 0.03), as RDP-supplemented animals consumed more supplement on a g·kg body weight (BW) d basis than RUP animals. There was an effect of protein type ( = 0.02) and delivery method ( = 0.03) on fluid flow rate, with RUP and HF cows having greater liquid flow rates. Ruminal pH was lower ( < 0.01) in RDP-HF cows than RDP-SF cows at all hours, except 4-h post-feeding. RDP-SF animals had the greatest ( < 0.01) concentrations of ruminal ammonia. Valerate ruminal concentrations were greater ( = 0.04) in RDP supplemented animals compared to RUP supplemented animals. In conclusion, self-fed supplements containing RDP may enhance the use of low-quality forages and increase ruminal ammonia concentrations.
本研究的目的是评估蛋白质类型和投喂方式的差异对瘤胃动力学和养分消化的影响。将奶牛分为瘤胃可降解蛋白（RDP）组或瘤胃不可降解蛋白（RUP）组，并分别给予自喂（SF）盐限制压块饲料或人工投喂（HF）松散补充料，从而形成四种日粮处理方式。在中性洗涤纤维（NDF）摄入量上存在投喂方式效应（P = 0.04），因为自喂组动物比人工投喂组动物消耗更多的NDF。与其他三种处理方式相比，RDP - SF组动物具有更高的NDF消化率（P = 0.04）和水摄入量（P = 0.03）。补充料摄入量显示出蛋白质类型效应（P = 0.03），因为以每千克体重（BW）每天摄入克数计算，补充RDP的动物比补充RUP的动物消耗更多的补充料。在液体流速方面存在蛋白质类型效应（P = 0.02）和投喂方式效应（P = 0.03），RUP组和HF组奶牛的液体流速更高。除喂食后4小时外，RDP - HF组奶牛在所有时间点的瘤胃pH均低于RDP - SF组奶牛（P < 0.01）。RDP - SF组动物的瘤胃氨浓度最高（P < 0.01）。与补充RUP的动物相比，补充RDP的动物瘤胃戊酸浓度更高（P = 0.04）。总之，含有RDP的自喂补充料可能会提高低质量饲草的利用率并增加瘤胃氨浓度。
