Longevity and efficiency associated with age structures of female pigs and herd management in commercial breeding herds.
Annual performance measurements, age structures of female pig inventories, and by-parity culling rates were abstracted from data files of 110 herds that participated in a data-share program in Japan. Parity at culling was used as a prime measurement of longevity, whereas pigs weaned x mated female(-1) x year(-1) (PWMFY) was a prime measurement of reproductive efficiency. High or low longevity herds were based on the greatest 50% of the herds or the remaining herds ranked by parity at culling, whereas high or low reproductive efficiency herds were grouped according to the greatest 50% of the herds or the remaining herds ranked by PWMFY. Measurements were analyzed as a 2 x 2 factorial arrangement, using the main effects of the 2 herd groups of longevity (high or low) and reproductive efficiency (high or low). Means of parity at culling and PWMFY were 4.6 (SD = 0.82) and 21.2 (SD = 3.02), respectively. The high longevity group had 1.27 greater parities at culling than the low longevity group (P < 0.05), but no differences between the high and low longevity groups were found in PWMFY (P = 0.21). No differences between the high and low efficiency groups were found in parity at culling (P = 0.50). No interactions between the longevity and efficiency groups were found on any longevity or efficiency measurement (P > 0.20). In herd management, the percentage of reserviced females and the percentage of multiple matings were associated with the longevity group and the efficiency group (P < 0.05). The high longevity group had lower culling rates in parity 0 to 6 than the low longevity group (P < 0.05), whereas no differences between the low and high efficiency groups were found in culling rates in parity 0 to 2 (P > 0.20). This study suggests that measures to achieve longevity and high reproductive efficiency in breeding herds do not conflict and that high reproductive efficiency and high longevity can be achieved.
Koketsu
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School of Agriculture, Meiji University, Kawasaki 214-8571 Japan. koket001@isc.meiji.ac.jp
D000375:Aging / Q000502:physiology*; D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D005260:Female; D008136:Longevity / Q000502:physiology*; D012098:Reproduction / Q000502:physiology*; D013552:Swine / Q000502:physiology*