J. Anim Sci.
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J. Anim Sci. 1985. 61:1327-1334.
© 1985 American Society of Animal Science
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Interval to First Postweaning Estrus and Causes for Leaving the Breeding Herd in Large White, Landrace, Yorkshire and Chester White Females After Three Parities1

R. R. Maurer, J. J. Ford and R. K. Christenson

U.S. Department of Agriculture2,3,, Clay Center, NE 68933

Abstract

Three hundred and five Large White (LW, 93), Landrace (L, 92), Yorkshire (Y, 69) and Chester White (CW, 51) gilts produced at the Roman L. Hruska U.S. Meat Animal Research Center over 3 yr with 15 to 41 gilts per breed group per year were housed in total confinement and mated to farrow at 1 yr of age. After 28 to 30 d lactation, piglets were weaned and all females were observed for estrus daily for 30 d. During the year that each gilt initially farrowed, she was mated to produce a second and third litter if she returned to estrus within 30 d after piglet removal. Interval from weaning (d 0) to estrus and reason for leaving the breeding herd were recorded for each animal. Interval from weaning to estrus was influenced by breed (P<.01), parity (P<.01) and interaction between breed and parity (P<.01). Intervals from weaning to estrus, in first parity females which exhibited estrus, were 7.8, 6.6, 9.3 and 14.0 d for the LW, L, Y and CW breeds. Intervals for all females after the second litter were 6.8, 4.9, 8.0 and 9.1 d, and after the third litter 6.4, 5.2, 8.3 and 10.1 d for the LW, L, Y and CW breeds. Breed, parity and year (P<.01) affected the number of females not exhibiting estrus. Percentages of females not exhibiting estrus were 6.5, 18.7, 37.7 and 23.5 for the LW, L, Y and CW breeds and 16.1, 2.3 and 2.0 for sows after the first, second and third parities. Percentages of deaths for LW, L, Y and CW sows were 4.3, 4.3, 4.3 and 17.6 (P<.01). Percentage of females failing to maintain a pregnancy was 19.4, 5.4, 2.9 and 19.6 for the LW, L, Y and CW breeds. Percentage of sows available to produce a fourth litter was higher (P<.01) for LW (63.4) and L (62.0) than for Y (52.2) and CW (35.3) breeds.

Footnotes

1 The authors are grateful to Ed McReynolds, Russell Boatman and Charolotte Scott for the care and breeding of the sows and to Cheryl Yates and Linda Parnell for stenographic work. Cooperation of the Nebraska Agr. Exp. Sta., Univ. of Nebraska, Lincoln, is acknowledged.

2 Mention of a trade name, proprietary product or specific equipment does not constitute a guarantee or warranty by the USDA and does not imply its approval to the exclusion of other products that may also be suitable.

3 Agr. Res. Service, Roman L. Hruska U.S. Meat Animal Research Center.






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Copyright © 1985 by the American Society of Animal Science.