Reynolds C K, Crompton L A, Jones A K, Bartram C G
Centre for Dairy Research, School of Agriculture, Policy and Development, University of Reading, Earley Gate, Reading, RG6 6EU, United Kingdom.
Mole Valley Farmers Ltd., South Molton, Devon, EX36 3LH, United Kingdom.
JDS Commun. 2025 Mar 18;6(3):324-328. doi: 10.3168/jdsc.2024-0689. eCollection 2025 May.
The objective was to determine the effects of a daily rumen drench of maize gluten meal, as a source of RUP, and rumen-protected Met, Lys, and His for the first 4 d of lactation on DMI and milk production and composition of dairy cows during their first 12 wk of lactation. Twenty multiparous Holstein cows were randomly assigned at calving to a control rumen drench of 30 L of warm water or a 30-L aqueous suspension of maize gluten meal and rumen-protected Met, Lys, and His calculated to provide Met, Lys, His, and Leu for absorption equal to their amounts in 600 g of casein. Cows received their first drench within 8 h of calving and then again 24, 48, and 72 h later. Cows were fed a TMR for ad libitum consumption and at 7 DIM cows were moved from calving boxes to a cubicle yard, and measurements of daily DMI and milk yield and weekly milk composition, BW, and BCS were obtained through wk 12 postpartum. A blood plasma sample obtained at 7 DIM was analyzed for metabolite, protein, and albumin concentration. There was no effect of treatment on DMI or milk yield, but milk fat concentration was higher and milk protein concentration tended to be higher for treated cows during wk 2 to 12. While BCS was not affected, treated cows gained BW over the course of the study (+32 kg), whereas control cows maintained a similar BW (-3 kg). Plasma metabolite and protein concentrations were not affected by treatment. Four daily rumen doses of supplemental RUP and rumen-protected EAA, initiated within hours of calving, had sustained positive effects on milk fat and protein concentration and BW of lactating Holstein cows, suggesting homeorhetic effects that warrant further investigation.
本研究旨在确定在泌乳期的前4天，每日向瘤胃灌注玉米蛋白粉（作为瘤胃非降解蛋白来源）以及瘤胃保护性蛋氨酸、赖氨酸和组氨酸，对奶牛在泌乳期前12周的干物质采食量（DMI）、产奶量和乳成分的影响。20头经产荷斯坦奶牛在产犊时被随机分配，一组接受30升温水的对照瘤胃灌注，另一组接受30升玉米蛋白粉与瘤胃保护性蛋氨酸、赖氨酸和组氨酸的水悬浮液灌注，其计算量能提供与600克酪蛋白中蛋氨酸、赖氨酸、组氨酸和亮氨酸吸收量相等的量。奶牛在产犊后8小时内接受首次灌注，然后在24、48和72小时后再次灌注。奶牛自由采食全混合日粮（TMR），在产后7天，奶牛从产犊栏转移到小隔间牧场，并在产后12周内每天测量DMI和产奶量，每周测量乳成分、体重（BW）和体况评分（BCS）。在产后7天采集的血浆样本用于分析代谢物、蛋白质和白蛋白浓度。处理对DMI或产奶量没有影响，但在第2至12周，处理组奶牛的乳脂肪浓度较高，乳蛋白浓度也有升高趋势。虽然BCS不受影响，但在研究过程中，处理组奶牛体重增加（+32千克），而对照组奶牛体重维持在相似水平（-3千克）。血浆代谢物和蛋白质浓度不受处理影响。在产犊后数小时内开始的每日4次瘤胃补充瘤胃非降解蛋白和瘤胃保护性必需氨基酸，对泌乳荷斯坦奶牛的乳脂肪和蛋白质浓度以及体重有持续的积极影响，表明存在同功调节效应，值得进一步研究。
