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

在奶牛从干期过渡到哺乳期期间，乳品生产者一直面临着确保其采食量一致的挑战，以减少产后疾病并促进生产。产犊后患一种或多种代谢疾病的奶牛产奶量低、繁殖性能下降、其他疾病风险增加、生产效率降低的风险较高，因此利润较低。亚临床酮症（SCK）与这一时期的低采食量有关，是影响许多奶牛的一种健康状况，估计发病率为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，影响多达30%的泌乳奶牛，在泌乳早期发病率最高。在过渡期间，从数量和一致性（即减少分选）两方面提高摄入量的一种潜在方法是使干牛口粮和新鲜牛口粮在物理成分上看起来相似。本研究的目的是确定是否可以提高产犊前的采食量，是否可以阻止饲料分选，以及产犊后采食量的一致性，通过饲喂在物理特性方面更接近于泌乳牛的干牛日粮。在两项研究中，我们将测试经济有效的方法，使干牛口粮在物理上与泌乳日粮更相似，特别是通过改变饲料（稻草）颗粒长度和通过添加水。我们预测，这些日粮调整不仅可以减少干期的分拣和提高采食量，而且可以延续改善泌乳期早期的营养摄入和能量平衡。从这些结果来看，奶牛的健康、福利和效率的改善不仅将使加拿大乳制品生产商获得更多利润，而且还将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.