Manipulating dry cow diets to ensure consistency in feed intake across the transition period

乳制品生产商不断面临挑战，即在奶牛从干奶期过渡到泌乳期时确保奶牛的饲料摄入量一致，以减少产后疾病并促进生产。产犊后死于一种或多种代谢疾病的奶牛具有产奶量低、繁殖性能降低、其他疾病风险增加和生产效率降低的较高风险，因此利润较低。亚临床酮病（SCK）与这段时间内的低采食量有关，是影响许多奶牛的一种健康状况，估计发病率> 40%。同样，亚急性瘤胃酸中毒（SARA），通常与营养摄入不平衡（可能是由于饲料分选）有关，影响高达30%的泌乳奶牛，在泌乳早期发生率最高。在整个过渡期内，在量和一致性（即减少分选）方面改善摄入量的一种潜在方法是使干和新鲜奶牛日粮的物理组成相似。本研究的目的是确定是否可以改善产犊前的采食量，是否可以阻止饲料分选，以及是否可以通过饲喂在物理特性方面更接近泌乳期奶牛饮食的干奶牛饮食来保持产犊后采食量的一致性。在两项研究中，我们将测试使干奶牛日粮在物理相似性方面更接近泌乳期日粮的成本效益方法，特别是通过改变饲料（秸秆）颗粒长度和通过添加水。我们预测，这些口粮的修改不仅会减少分拣和改善在干奶期的摄入量，但结转，以改善营养摄入和能量平衡在泌乳早期。从这些结果来看，奶牛健康、福利和效率的改善不仅可以让加拿大乳制品生产商获得更多利润，还可以增加消费者对这一农业部门的信心。

Dairy producers are continually challenged with ensuring consistent feed intake in their cows as they transition from the dry period to lactation, to reduce post-partum diseases and promote production. Cows that succumb to one or more metabolic diseases after calving are at higher risk of low milk production, reduced reproductive performance, increased risk of other disease, and lower efficiency of production, and thus are less profitable. Subclinical ketosis (SCK), related to low feed intake during this time period, is one health condition that impacts many cows, with an estimated incidence of >40%. Similarly, subacute ruminal acidosis (SARA), often related to imbalanced nutrient intake (possibly due to feed sorting) impacts up to 30% of lactating cows, with highest incidence in early lactation. A potential method of improving intake, both in terms of amount and consistency (i.e. reduced sorting) across the transition period would be to make the dry and fresh cow rations appear similar, in physical composition. The objective of this research is to determine if pre-calving feed intake can be improved, feed sorting can be discouraged, as well as consistency in intake maintained after calving, by feeding dry cow diets that more closely resemble lactating cow diets in terms of physical characteristics. In two studies we will test cost-effective methods of making dry cow rations more similar in physical resemblance to lactating diets, specifically by changing forage (straw) particle length and through the addition of water. We predict that these ration modifications will not only reduce sorting and improve intake during the dry period, but carry over to improve nutrient intake and energy balance in early lactation. From these results, improvements in health, welfare, and efficiency of dairy cows will not only allow Canadian dairy producers to be more profitable, but also increase consumer confidence in this agricultural sector.