Replacement heifers play an integral role in the success of a dairy operation. Too often heifers are lost to perinatal mortality, which can make meeting replacement goals difficult. New research conducted by Dr. Jessica Brickell at the Royal Veterinary College in London evaluated the association of single nucleotide polymorphisms (SNP) in the leptin gene with perinatal mortality. This research includes analyzed data from 385 Holstein heifers on 18 United Kingdom dairy farms.

In order to better understand this research, we talked with Dr. Brickell about her research and how the discovery has the potential to reduce perinatal mortality within the dairy industry.

Tell us a little about your work with the leptin gene.

The interest on this topic came along with my position in the Department of Veterinary Basic Sciences at the Royal Veterinary College in London. The dairy heifer calf is a potential herd replacement; tackling herd reproductive performance assessment should start with the heifer calf. Most studies focus on the lactating dairy cow and few study heifers during the heifer rearing period. My research focused primarily on the growth, development and survival of dairy heifers during the rearing period and throughout first lactation.

Rearing the required numbers of heifer replacements annually is a key factor in profitable dairy operations. Perinatal mortality—defined as stillbirths and mortality within 24 hours of parturition—is a major contributing factor to heifer losses in the dairy industry. We and others have previously estimated perinatal mortality in Holsteins to be at 6 to 8 percent. These levels are often twice as high in heifers at first calving compared with multiparous cows (12 – 13 percent vs. 6 percent). Thus, perinatal mortality in dairy cattle is clearly a challenge for dairy producers today.

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