Effects of boar contact and housing conditions on estrus expression in sows.
In this paper, the authors review the effects of boar contact and different components of boar presence on onset and expression of estrus in weaned sows. Evidence is presented that boar contact may influence LH release, onset of follicle development and timing of ovulation after weaning. Once the sow is in estrus it is important that she shows estrous behavior, because her expression of estrus determines whether she will be inseminated. Boar contact or components thereof affect expression of estrus in sows. There are distinct differences between different components of boar contact in their effectiveness in the induction of estrous behavior (standing response) in sows. Habituation to boars (due to frequency of boar contact or housing of boars near sows) also affects estrus expression in sows. It is important to inseminate sows at the correct moment relative to ovulation. The use of different estrus detection protocols (e.g., by giving sows different levels of boar stimuli during estrus detection) may result in the definition of distinct periods of estrus that may help to predict the moment of ovulation. However, results to date are not very encouraging. Besides boar stimuli, the housing conditions of sows may affect onset of estrus and estrus expression. This paper focuses on social sow-to-sow interactions. The effects of group housing (as compared to individual housing) on onset of estrus and expression of estrus are equivocal. These effects likely depend on factors like aggression between pen mates, reproductive status of pen mates and social rank of sows within the group.
Kemp
B
B
Department of Animal Sciences, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands. bas.kemp@wur.nl
Soede
N M
NM
Langendijk
P
P
D000818:Animals; D004971:Estrus / Q000502:physiology*; D005260:Female; D006799:Housing, Animal; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D006080:Ovarian Follicle / Q000502:physiology; D010060:Ovulation; D012098:Reproduction / Q000502:physiology; D012726:Sexual Behavior, Animal / Q000502:physiology*; D013552:Swine / Q000502:physiology*; D014886:Weaning
D007986:Luteinizing Hormone