Zoetis this week introduces its new Clarifide Plus genomics test, complete with two selection indexes, to allow dairy producers to include cattle wellness in their genetic criteria. The new test and associated indexes will provide rankings for resistance or susceptibility to mastitis, lameness, metritis, retained placenta, displaced abomasum and ketosis.
According to Zoetis technical services geneticist David Erf, the company develops the genomic tests and rankings based on more than 10 million lactation records from cows in more than 200 commercial U.S. dairy herds. The reliabilities for the wellness traits average 50%, compared to parent-average reliabilities of 16 to 19%, and statistical accuracy for the wellness traits averages around 70% compared to about 42% for parent average.
Erf also points out that the ratings predict direct traits, rather than indicator traits, such as a prediction for mastitis, rather than for somatic cell counts, and for lameness rather than for food and leg scores. Zoetis researchers confirmed the rankings are closely correlated with those for the indicator traits while providing greater reliability.
Zoetis incorporates wellness rankings into two selection indexes to simplify use and to avoid the pitfalls of single-trait selection. The Dairy Wellness Profit Index (DWP$) incorporates the rankings for wellness traits into the broader Clarifide index, including traits relating to production, fertility, milk quality and longevity, similar to the familiar NetMerit (NM$) index. The mathematical weighting of traits is somewhat different with the DWP$ index, placing somewhat less emphasis on production and fertility. By incorporating wellness traits into the index, producers can select females that will achieve productivity levels closer to their full genetic potential, resulting in higher overall productivity even if that genetic potential is somewhat lower. According to Zoetis, the DWP$ index should provide an average of improvement of about $55 per heifer in overall returns compared with NM$ due to improved health and reduced health-related costs. Based on research in cooperator herds, the company estimates a $1,248 lifetime difference in returns between animals ranking in the top 10th percentile for DWP$ versus those in the 90th percentile.
The company also offers a Wellness Trait Index (WT$), which focuses entirely on the six wellness traits. The WT$ index places weightings of 41% on mastitis, 27% on lameness, 19% on metritis, 6% each on retained placentas and displaced abomasum, and 1% on ketosis. Zoetis estimates the WT$ index will provide about a $520 lifetime difference per heifer between those in the 10th versus the 90th percentile. Erf says the WT$ index will fit best with dairies that have developed their own proprietary selection index, allowing them to incorporate rankings for wellness traits into an overall index tailored to their specific genetic goals.
As with other selection indexes, dairies can use the information from DWP$ or WT$ in a variety of ways, particularly as they use genomic testing in replacement heifers. For example, a dairy might decide to cull the lowest-ranking heifers, breed the next-lowest group with conventional semen or beef-breed semen, and selecting the top 50 percent for breeding with sexed semen from top sires or for use in embryo transfer or in-vitro fertilization programs.
Erf says these new tests and indexes could provide a service opportunity for veterinarians, who can incorporate genetic selection into their overall herd-health programs and help clients understand the application of genomic-enhanced selection indexes. Also, veterinarians can help clients recognize that genetic selection, even with enhancements offered by genomic technologies, cannot stand alone in herd health and productivity. A cow can only reach her full genetic potential under optimal management and environmental conditions. Management and preventative measures such as cattle comfort, nutrition, vaccinations, biosecurity and sanitation must work in concert with genetics for dairies to achieve optimal results from their investments in genetic selection.
Shortly after Zoetis launched Clarifide Plus on March 1, Semex announced it will offer the new index in its sire listings, along with its Immunity+ product. “Zoetis’ new Dairy Wellness Profit Index is another tool we’re pleased to offer Semex clients,” says Paul Krueger, Semex Immunity+ Global Brand Manager and Director, Sales and Business Development, United States. “We firmly believe in putting our clients’ needs first, and offering them the very best genetic solutions. Adding DWP$ to our lineup alongside NM$, GTPI and other profit indexes offers our clients additional information in their decision making process.”