Recent research from Michigan State University indicates that the association between milk production and fertility of dairy cows is more complex and multilayered than previously thought, according to results published in the latest Michigan Dairy Review.
The researchers developed cutting-edge statistical methods to take a fresh, deeper look into the relationship between milk yield and fertility in dairy cows. They applied these research methods to large Dairy Herd Improvement Association data sets from Michigan several hundred farms, comprising of more than 120,000 cows calving during 2005 and 2006.
The research methods were novel in that the researchers deliberately accounted for cows and herds as separate units of performance that are interconnected with each other as cows are managed within herds.
The results provide solid evidence that it is an over-simplification to think that “one-size-fits-all” describes the relationship between milk yield and reproductive performance of dairy cows. Instead, the production-reproduction relationship is highly variable and differs with management practices and characteristics of the herd.
This is certainly good news as it implies that it might be possible to enhance or fine-tune farm management to jointly optimize both milk yields and dairy cow reproduction, say the scientists.
In particular, highly specialized management practices that typically characterize intensive production systems, such as rbST supplementation and 3X milking frequency, were associated with a favorable link between milk yield and reproduction. In other words, under intensive management, high milk yields did not necessarily match up with poor reproduction. In some cases, the opposite was actually true and high milk yield went hand in hand with good reproductive performance.
Therefore, high milk yield does not mean that cows will definitely have poor reproductive performance.
In fact, it is apparent that high quality management upon which high production is based also can support good reproductive performance. So, keep an open mind when it comes to reproductive expectations of your high producing cows and give them the very best management and attention available, the researches suggest.