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Copyright © 2015
Angus Journal


A Steady Diet

Managing heifers to avoid stress-induced fertility issues can set them up for a longer stay in the herd.

SIOUX FALLS, S.D. (Dec. 4, 2012) — How important is beef cow longevity? That was a question posed by South Dakota State University (SDSU) reproductive physiologist George Perry during the Applied Reproductive Strategies in Beef Cattle (ARSBC) symposium Dec. 3-4, in Sioux Falls, S.D.

George Perry George Perry noted that consistently better pregnancy rates are achieved when heifers are developed on grass from weaning to breeding.

"Research has indicated it takes the net revenue from approximately six calves to cover the development and production costs of each replacement heifer," said Perry. “In addition, any cow that misses a single calving is not likely to recover the lost revenue of that missed calf. That makes longevity of a beef female pretty important to the sustainability and profitability of any beef operation.”

Perry urged his audience to consider that, according to National Animal Health Monitoring System (NAHMS) data, problems related to reproduction are the leading reasons for culling cows. Failure to breed and other fertility problems account for 37% of females eliminated from breeding herds.  Furthermore, greater than 15% of animals culled were less than 5 years of age, and nearly 32% were between the ages of 5 and 9 years.

"Females that are culled from a herd prior to producing six calves increase the developmental cost of other heifers and do not contribute to the profitability and sustainability of the operation," added Perry. "Therefore, understanding how management decisions impact pregnancy success and longevity will have an effect on profitability and sustainability."

According to Perry, a common approach to replacement heifer development may contribute to reproductive failure. This can occur when heifers are grown and prepared for breeding while confined to a feedlot. Heifers may then be turned out to pasture for natural service, or turned out after artificial insemination (AI). The change in environment, including an abrupt change in diet, may trigger a period of weight loss. For heifers exposed to natural service, the ability to conceive may be hindered. Embryo survival may be jeopardized among heifers very recently bred by AI.

Perry noted that consistently better pregnancy rates are achieved when heifers are developed on grass from weaning to breeding. This development method may not be possible for many producers, and Perry admitted there is no single "best" way to develop heifers.

"It is best to avoid big changes in diet at breeding or right after AI. It's particularly important that heifers don't go through a period of negative energy intake," said Perry.

Managing heifers to conceive early in the breeding season is a first step toward improving longevity of the herd, but Perry emphasized that managing heifers to minimize embryonic losses is essential to maximizing productivity.

Perry spoke during Tuesday's ARSBC session focused on management of stress. Visit the Newsroom at www.appliedreprostrategies.com to listen to his presentation and to view the accompanying PowerPoint and proceedings paper.

Comprehensive coverage of the symposium is available online at www.appliedreprostrategies.com. Compiled by the Angus Journal editorial team, the site is made possible through sponsorship by the Beef Reproductive Task Force and LiveAuctions.tv.

Editor's Note: This article was written under contract or by staff of the Angus Journal. To request reprint permission and guidelines, contact Shauna Rose Hermel, editor, at 816-383-5270.