Albornoz Rodrigo I, Russo Victoria M, Ho Christie K M, Giri Khageswor, Allen Michael S, Lock Adam L, Wales William J, Knight Matthew I
Agriculture Victoria Research, Department of Energy, Environment and Climate Action, Ellinbank, Victoria 3821, Australia.
Agriculture Victoria Research, Department of Energy, Environment and Climate Action, Bundoora, Victoria 3083, Australia.
Animals (Basel). 2024 Dec 16;14(24):3622. doi: 10.3390/ani14243622.
This experiment determined the effects of two different starch sources when offered twice a day to cows during the early postpartum period (1 to 23 d postpartum, treatment period) on dry matter intake (DMI), feeding behavior, and milk production. The subsequent effects on milk production in the carryover period (24 to 72 d) where cows received a common diet (grazed perennial ryegrass pasture plus concentrate supplements) were also measured. Thirty-two multiparous dairy cows were offered concentrate feed (8 kg DM/d) containing 5 kg DM of crushed wheat grain or ground corn grain (7 h in vitro starch digestibility of 65.8% and 58.8%, respectively). At each milking (morning and afternoon), cows were offered half of the concentrate feed, and upon return to their individual stalls, they were offered perennial ryegrass pasture silage (56.2% neutral detergent fiber (NDF), 39.8% acid detergent fiber (ADF), 16.6% crude protein (CP)) at 130% of their expected daily intake. Dry matter intake, milk yield, and body weight were recorded daily. Blood and milk sampling, body condition score, and feeding behavior measurements were performed weekly during the treatment period. During the carryover period, milk sampling and body condition score measurements were conducted on a weekly and fortnightly basis, respectively. In the treatment and carryover periods, there was no significant effect of starch source treatment on DMI, milk yield, milk composition, change in body weight, or body condition. Similarly, the starch source did not affect the concentrations of blood markers of energy status or inflammatory response. Despite differences in the in vitro starch fermentability between treatments, the starch source did not significantly affect production responses. It is possible that the elevated NDF and ADF concentrations of the forage offered during the treatment period, the limited difference in starch fermentability between treatments, and the temporal supply of fuels to the liver when starch sources were offered twice a day may have offset the effects of the type of starch source on DMI and production via physical signals associated with rumen fill and distention.
本实验测定了在产后早期（产后1至23天，治疗期）每天给奶牛投喂两次两种不同淀粉来源对干物质摄入量（DMI）、采食行为和产奶量的影响。还测定了在延续期（24至72天）奶牛采食普通日粮（多年生黑麦草牧场放牧加精料补充）时对产奶量的后续影响。给32头经产奶牛投喂含5千克干物质碎小麦粒或磨碎玉米粒的精料（8千克干物质/天）（体外淀粉消化率分别为65.8%和58.8%）。每次挤奶（上午和下午）时，给奶牛投喂一半精料，回到各自牛舍后，按预期日摄入量的130%给它们投喂多年生黑麦草青贮料（中性洗涤纤维（NDF）56.2%，酸性洗涤纤维（ADF）39.8%，粗蛋白（CP）16.6%）。每天记录干物质摄入量、产奶量和体重。在治疗期每周进行血液和乳汁采样、体况评分和采食行为测量。在延续期，分别每周和每两周进行一次乳汁采样和体况评分测量。在治疗期和延续期，淀粉来源处理对DMI、产奶量、乳成分、体重变化或体况均无显著影响。同样，淀粉来源也不影响能量状态或炎症反应的血液标志物浓度。尽管各处理间体外淀粉发酵能力存在差异，但淀粉来源对生产反应无显著影响。有可能是治疗期投喂的牧草中NDF和ADF浓度升高、各处理间淀粉发酵能力差异有限以及每天投喂两次淀粉来源时肝脏的燃料供应时间等因素，通过与瘤胃充盈和扩张相关的物理信号抵消了淀粉来源类型对DMI和生产的影响。
