Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Genomics and Improvement Laboratory » Research » Publications at this Location » Publication #402300
Research Project: Increasing Accuracy of Genomic Prediction, Developing Algorithms, Selecting Markers, and Evaluating New Traits to Improve Dairy Cattle

Location: Animal Genomics and Improvement Laboratory

Title: Haplotype inheritance and livability of recumbent Holstein calves

Author
item Al-Khudhair, Ahmed
item Vanraden, Paul
item Null, Daniel
item Neupane, Mahesh
item DECHOW, CHAD - Pennsylvania State University

Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/21/2023
Publication Date: 6/25/2023
Citation: Al-Khudhair, A.S., Van Raden, P.M., Null, D.J., Neupane, M., Dechow, C.D. 2023. Haplotype inheritance and livability of recumbent Holstein calves [abstract]. Journal of Dairy Science. 106(Suppl. 1):321(abstr. 1348T).

Interpretive Summary:

Technical Abstract: A recessive condition affecting calves’ ability to stand, termed recumbency, was reported by Dechow in 2022. The haplotype identified on chromosome 16 traced back 13 generations via several very popular sires back to 1952. For 70 years, it has been one of the most common haplotypes in the Holstein population, but the observed number of homozygotes was only slightly less than expected in national data. A potential explanation was if a new mutation had occurred within that popular haplotype. Computer code to sort out the mutated from the original version of the cholesterol deficiency haplotype was also applied to recumbency by requiring pedigree connections to a recent common ancestor of recumbent calves. For 5.1 million genotyped Holsteins, haplotype codes included 0.01% homozygotes tracing only to that ancestor on both sides (code 2), 0.44% other homozygotes (code 4) tracing to that ancestor on both sides but also to other sires having the original version, 12.4% not sure carriers (code 3) where the normal or mutated status of the haplotype could not be determined, 2.3% sure carriers (code 1), and 85% noncarriers (code 0). Haplotype status for 558K calves matched to heifer livability records; those were analyzed without adjusting for birth year or herd incidence. Only 46 code 2 homozygotes had records and 52% of those died before 18 months at an average age of 1.7±1.6 months. That death rate may be underestimated if only healthier calves were genotyped. The death rate was only 4.2% for the 2,211 code 4 homozygotes and 2.4% for the code 0 noncarriers. Of the 5 oldest code 2 heifers that lived beyond 18 months, most had 3 or 4 lactations with good production, but one died at two years of age. Thus, calves that recover from recumbency can have normal, productive lives. Instead of identifying known or suspected homozygotes from genotypes and then checking phenotypes, a more proactive strategy would be to identify carrier’s mating and carefully monitor the resulting calves but would require more effort. Different reporting methods or dominance effects may be needed to include recumbency and other partially lethal effects in selection and mating.