| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
ANIMAL PRODUCTION |
,4
* Department of Animal Sciences, Washington State University, Pullman 99164-6310 and
and
USDA, ARS, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT 59301
4 Correspondence: 243 Fort Keogh Rd. (phone: 406-232-8213; fax: 406-232-8209; e-mail: mike{at}larrl.ars.usda.gov).
Abstract
Objectives were to 1) identify risk factors affecting the longevity of beef females, 2) evaluate the utility of measures collected early in life in predicting longevity, and 3) estimate the heritability of longevity when females were culled primarily for not being pregnant following a 45-d breeding season. Data were from 1,379 Composite Gene Combination (CGC; 
Red Angus, 
Charolais, Tarentaise) cows born from 1982 through 1999 at the USDA-ARS, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT, and first calving at approximately 2 yr of age. The length of productive life was modeled using Cox regression to identify factors affecting the longevity of beef females. Age at first calving and calf birth weight did not influence longevity. Cows that experienced dystocia were at greater risk of being culled than those that calved without assistance (P < 0.01). On average, as breeding value for cow weight increased, the risk of being culled decreased (P < 0.01), whereas the risk of being culled increased with increasing maternal breeding values for preweaning gain (P < 0.05). Traits measured before 1 yr of age were not useful in predicting the subsequent longevity of cows. The heritability of functional longevity was estimated to be 0.14. Relatively low heritability and the lack of indicators of longevity expressed early in life suggest that genetic improvement of longevity will be difficult. Matching the genetic potential of cows for size and milk production to the production environment such that rebreeding performance is not compromised by concurrent lactation seems to be a consideration in retaining beef females when open cows are culled.
Key Words: Beef Cattle • Productive Life • Risk • Survival
This article has been cited by other articles:
|
|
 |
|
  K. M. Cammack, M. G. Thomas, and R. M. Enns Review: Reproductive Traits and Their Heritabilities in Beef Cattle Professional Animal Scientist, October 1, 2009; 25(5): 517 - 528. [Abstract] [PDF]
|
|
|
|
 |
|
 G. L. Bennett Experimental selection for calving ease and postnatal growth in seven cattle populations. I. Changes in estimated breeding values J Anim Sci, September 1, 2008; 86(9): 2093 - 2102. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. E. Ricklefs and C. D. Cadena Heritability of Longevity in Captive Populations of Nondomesticated Mammals and Birds J. Gerontol. A Biol. Sci. Med. Sci., May 1, 2008; 63(5): 435 - 446. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D. MacNeil and T. B. Mott Genetic analysis of gain from birth to weaning, milk production, and udder conformation in Line 1 Hereford cattle J Anim Sci, July 1, 2006; 84(7): 1639 - 1645. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D. MacNeil Genetic evaluation of the ratio of calf weaning weight to cow weight J Anim Sci, April 1, 2005; 83(4): 794 - 802. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Tarres, J. Casellas, and J. Piedrafita Genetic and environmental factors influencing mortality up to weaning of Bruna dels Pirineus beef calves in mountain areas. A survival analysis J Anim Sci, March 1, 2005; 83(3): 543 - 551. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
