Relationship between forage quality and dairy cattle production

The effect of forage quality on animal production is observed routinely in the field by farmers and nutritionists when switching from one forage or “batch” of forage to another. When production decreases, dietary adjustments sometimes reduce or eliminate the differences in production. However, altering supplementation strategy will not always allow one forage to achieve the same level of production as another. While it is clear that differences in ruminal degradation of forage components affect energy intake, absorbed protein and subsequent production, it has been difficult to assess their relationship quantitatively. This is because of the many interactions among forages, other dietary components, rumen microbes and animals that determine animal production. While many feeding studies have compared forages of different quality, few have tried to supplement each forage optimally. This has resulted in conflicting information in the literature. Since so many factors are involved in these interactions, virtually no two studies are alike. It is extremely difficult to conduct trials in which forages vary only in the forage quality factors of interest. Therefore, nearly all trials in the literature are confounded when one tries to evaluate the importance of specific factors.