Kleefisch Maria-Theresia, Zebeli Qendrim, Humer Elke, Gruber Leonhard, Klevenhusen Fenja
a Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health , University of Veterinary Medicine Vienna , Vienna , Austria.
b Agricultural Research and Education Centre Raumberg-Gumpenstein , Institute of Livestock Research , Irdning , Austria.
Arch Anim Nutr. 2018 Aug;72(4):290-307. doi: 10.1080/1745039X.2018.1474004. Epub 2018 Jun 1.
Dairy cows are commonly fed energy-dense diets with high proportions of concentrate feedstuffs to meet the increased energy needs of early lactation. However, feeding large amounts of concentrates may cause rumen acidosis and impact cow health. The hypothesis tested was that the energy supply and metabolic health of early-lactation Simmental cows can be maintained when high-quality hay rich in water-soluble carbohydrates (WSC) and crude protein (CP) is fed, despite the proportion of concentrates in the diet being reduced or even excluded. Twenty-four Simmental cows were allocated to one of four feeding groups beginning 10 d before the expected calving date, until 28 d thereafter. The feeding groups were 60CH (60% conventional fibre-rich hay plus 40% concentrate feed), 60HQH (60% high-quality hay plus 40% concentrate feed), 75HQH (75% high-quality hay plus 25% concentrate feed) and 100HQH (100% high-quality hay). The fibre-rich hay and high-quality hay differed in WSC content (110 g vs. 198 g of dry matter (DM)), neutral detergent fibre (646 g vs. 423 g of DM) and CP (65 g vs. 223 g of DM). Individual feed intake and milk production were monitored daily, and blood samples were collected weekly. Dry matter intake (DMI) and milk yield increased post partum, but 4 weeks post partum, the DMI of cows fed 100HQH only reached a daily mean DMI of 18.6 kg, whereas the DMI of the other groups averaged 21.9 kg (p < 0.046). The negative energy balance was less pronounced in cows fed 75HQH since they showed similar milk yields to the cows fed 60CH and 100HQH, but their energy intake was higher. Concentrations of milk components were similar across rations 60CH, 60HQH and 75HQH, as were most of blood parameters. Cows fed 100HQH responded to the energy deficit post partum with a higher ratio of non-esterified fatty acids to cholesterol and a higher concentration of ß-hydroxybutyrate (significant in comparison to cows fed 75HQH, p < 0.05). In conclusion, feeding high-quality hay with a WSC content of 20% in DM has the potential to decrease the proportion of concentrates in dairy cow feeding in early lactation, but cannot fully replace their supplementation due to a limited rumen capacity for forage intake.
奶牛通常被饲喂能量密集型日粮，其中精饲料比例较高，以满足泌乳早期增加的能量需求。然而，大量饲喂精饲料可能会导致瘤胃酸中毒并影响奶牛健康。本试验所验证的假设是，尽管日粮中精饲料比例降低甚至不使用精饲料，但当饲喂富含水溶性碳水化合物（WSC）和粗蛋白（CP）的优质干草时，泌乳早期西门塔尔奶牛的能量供应和代谢健康能够得到维持。从预计产犊日期前10天开始，直至此后28天，将24头西门塔尔奶牛分配到四个饲养组之一。饲养组分别为60CH（60%常规富含纤维的干草加40%精饲料）、60HQH（60%优质干草加40%精饲料）、75HQH（75%优质干草加25%精饲料）和100HQH（100%优质干草）。富含纤维的干草和优质干草在WSC含量（干物质（DM）分别为110克和198克）、中性洗涤纤维（DM分别为646克和423克）和CP（DM分别为65克和223克）方面存在差异。每天监测个体采食量和产奶量，并每周采集血样。产后干物质采食量（DMI）和产奶量增加，但产后4周，仅饲喂100HQH的奶牛的DMI每日平均仅达到18.6千克，而其他组的DMI平均为21.9千克（p<0.046）。饲喂75HQH的奶牛负能量平衡不太明显，因为它们的产奶量与饲喂60CH和100HQH的奶牛相似，但能量摄入量更高。60CH、60HQH和75HQH日粮组的乳成分浓度相似，大多数血液参数也相似。饲喂100HQH的奶牛产后对能量不足的反应是，非酯化脂肪酸与胆固醇的比例更高，β-羟丁酸浓度更高（与饲喂75HQH的奶牛相比有显著差异，p<0.05）。总之，饲喂DM中WSC含量为20%的优质干草有可能降低泌乳早期奶牛日粮中精饲料的比例，但由于瘤胃对草料的采食能力有限，不能完全替代精饲料的补充。
