Cooler cows have healthier calves

Calves born to cows experiencing heat stress during early pregnancy experience related effects that continue throughout their lives, according to a new study from the Journal of Dairy Science®


Philadelphia, PA, July 25, 2017

Environmental influences affecting cows during pregnancy have been shown to induce life-long physical and metabolic changes in the offspring. To learn more about the effects of heat stress on calves conceived during the summer, Pablo Pinedo, from Colorado State University, and Albert De Vries, from the University of Florida, examined data from more than 150 herds of dairy cattle in Florida, where cows experience hot summers and mild winters.

Previous studies have shown many different effects related to environmental or dietary stressors during pregnancy on the resulting offspring, both as calves and as adult cows, and summer heat is a significant environmental stressor in many areas of the United States. The researchers assessed seasonal effects on pregnancy by examining more than 667,000 records from Holstein cows calving in Florida between 2000 and 2012. Using environmental data from the National Oceanic and Atmospheric Administration, the researchers estimated the resulting heat stress on each of the 152 herds by comparing milk yield during summer and winter months to identify which herds were most likely to suffer from heat stress during the summer.

The researchers found that milk production was greater for cows born to a mother that conceived in the winter compared with cows born to a mother that conceived in the summer, with greater milk fat and protein yield. The odds of survival to a second calving were 1.15 to 1.21 times greater for cows arising from a winter-time conception compared with a summer-time conception.

“Our results showed that cows that arose from a pregnancy conceived in winter had, on average, better survival, better reproduction, and greater milk production than cows arising from a summertime pregnancy,” lead author Pablo J. Pinedo said. “These effects were more pronounced among first-parity cows compared with older cows.”

Although previous studies reported the effects of heat stress during late pregnancy, results from this study suggest that heat stress at the time of conception may permanently program the genetics of the adult animal by affecting epigenetic processes within the early embryo. For some of the analyzed variables, the differences were moderate, and the variation among individuals and operations is highly dependent on management practices.

“This report adds to a growing body of literature that supports careful management of the mother at all stages of the pregnancy to ensure the highest level of productivity in the offspring,” commented Matt Lucy, Editor-in-Chief of the Journal of Dairy Science. The researchers anticipate further research into the potential mechanisms associated with the reported effects.

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Notes for editors
“Season of conception is associated with future survival, fertility, and milk yield of Holstein cows,” by P. J. Pinedo and A. De Vries (https://doi.org/10.3168/jds.2017-12662). It appears in the Journal of Dairy Science, volume 100, issue 8 (August 2017) published by Elsevier.

Full text of the article is available to credentialed journalists upon request; contact Eileen Leahy at +1 732-238-3628 or jdsmedia@elsevier.com to obtain copies. To schedule an interview with the authors, please contact Pablo Pinedo at Pablo.Pinedo@colostate.edu.

About the Journal of Dairy Science®
The Journal of Dairy Science (JDS), official journal of the American Dairy Science Association®, is co-published by Elsevier and FASS Inc. for the American Dairy Science Association. It is the leading general dairy research journal in the world. JDS readers represent education, industry, and government agencies in more than 70 countries, with interests in biochemistry, breeding, economics, engineering, environment, food science, genetics, microbiology, nutrition, pathology, physiology, processing, public health, quality assurance, and sanitation.

About the American Dairy Science Association (ADSA)
The American Dairy Science Association (ADSA) is an international organization of educators, scientists, and industry representatives who are committed to advancing the dairy industry and keenly aware of the vital role the dairy sciences play in fulfilling the economic, nutritive, and health requirements of the world's population. It provides leadership in scientific and technical support to sustain and grow the global dairy industry through generation, dissemination, and exchange of information and services. Together, ADSA members have discovered new methods and technologies that have revolutionized the dairy industry. www.adsa.org

About Elsevier
Elsevier is a global information analytics business that helps institutions and professionals progress science, advance healthcare and improve performance for the benefit of humanity. Elsevier provides digital solutions and tools in the areas of strategic research management, R&D performance, clinical decision support, and professional education; including ScienceDirect, Scopus, SciVal, ClinicalKey and Sherpath. Elsevier publishes over 2,500 digitized journals, including The Lancet and Cell, more than 35,000 e-book titles and many iconic reference works, including Gray's Anatomy. Elsevier is part of RELX Group, a global provider of information and analytics for professionals and business customers across industries. www.elsevier.com

Media contact
Eileen Leahy
Elsevier
+1 732-238-3628
jdsmedia@elsevier.com