Influence of stage of gestation at grouping and presence of boars on farrowing rate and litter size of group-housed sows
Glen Cassar, DVM, PhD; Roy N. Kirkwood, DVM, PhD, Diplomate ECAR; Monica J. Seguin, MSc; Tina M. Widowski, PhD; Abdolvahab Farzan, DVM, MSc, PhD; Adroaldo J. Zanella, DVM, PhD; Robert M. Friendship, DVM, MSc, Diplomate ABVP
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Objective: To determine the impact of stage of pregnancy at grouping and presence of boars on fertility of group-housed sows.
Materials and methods: In Experiment One, 617 mixed-parity weaned sows were assigned at the time of insemination to be housed individually or in groups of 15. Each group of 15 unfamiliar sows comprised three sows at each of 2, 7, 14, 21, and 28 days from breeding. Sows were floor-fed a standard gestation ration once daily (approximately 2.5 kg per sow). After 5 weeks in groups, sows were re-housed in individual stalls until farrowing. In Experiment Two, 1584 sows on two farms were relocated after insemination to outdoor paddocks in groups of approximately 50, with or without inclusion within the group of three mature boars. Sows and boars were allowed ad libitum access to feed for an 8-hour period every third day, and the boars were removed after 2 weeks.
Results: In Experiment One, there was no effect of grouping per se, or day of gestation when grouped, on farrowing rate or subsequent litter sizes. In Experiment Two, farrowing rates and litter sizes were not affected by boar exposure.
Implications: These data indicate that sows can be successfully group-housed during gestation. Inclusion of boars in the social group does not improve fertility of group-housed sows.
Keywords: sows, boars, group housing, fertility
Cite as: Cassar G, Kirkwood RN, Seguin MJ, et al. Influence of stage of gestation at grouping and presence of boars on farrowing rate and litter size of group-housed sows. J Swine Health Prod 2008;16(2):81-85.
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