Effect of housing system and boar exposure on estrus expression in weaned sows

• Published in: Journal of animal science 2004-10, Vol.82 (10), p.3088-3093
• Main Authors: Knox, R.V, Breen, S.M, Willenburg, K.L, Roth, S, Miller, G.M, Ruggiero, K.M, Rodriguez-Zas, S.L
• Format: Article
• Language: English
• Subjects: Animal productions; Animals; Biological and medical sciences; boar contact; boar exposure; boars; Breeding - methods; crates; estrus; Estrus - physiology; estrus detection; Estrus Detection - methods; Female; Fundamental and applied biological sciences. Psychology; Housing, Animal; Male; pens; Random Allocation; Reproduction; reproductive behavior; reproductive efficiency; sexual behavior; Sexual Behavior, Animal; sows; Swine - physiology; swine housing; Terrestrial animal productions; Time Factors; Vertebrates; Weaning
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/2004.82103088x

Reproductive efficiency depends on detection of estrus, which may be influenced by housing and boar exposure. This experiment investigated the effects of housing system and boar contact on measures of estrus in weaned sows. Mixed-parity sows were randomly assigned to be weaned into gestation crates away from boars (AWC, n = 45), into pens away from boars (AWP, n = 42), or into pens adjacent to a mature boar (ADJ, n = 46). Estrus detection was initiated at approximately 0700 (0 h) and again at 0.25-, 0.5-, 1-, 2-, 4-, and 8-h intervals beginning on d 4 and continuing through d 7 following weaning. Estrus detection involved observation of the standing response after application of nose-to-nose boar exposure, backpressure, and side rubbing. For the AWC sows, a mature boar was moved to the front of the crates for a 10-min period and then removed. Sows housed in AWP were moved approximately 15 m to an empty pen adjacent to a mature boar for a 10-min period, and then returned to their pen. Sows housed ADJ were not moved and estrus detection was performed in their home pen for a 10-min period. The proportion of sows expressing estrus within 7 d from weaning was lowest for ADJ (80%, 37/46) compared with AWP (98%, 41/42) and AWC (96%, 43/45; P < 0.05). There was an effect of interval from weaning to estrus on the percentage of sows expressing estrus, but there was no interaction with treatment. Sows in AWC and AWP (4.7 d) had decreased (P = 0.01) intervals from weaning to estrus compared with ADJ (5.2 d). The duration of estrus was also shorter (P < 0.001) for ADJ (45 h) compared with AWC (58 h) or AWP (62 h). There was a treatment x interval x day of estrus effect for the percentage of sows expressing estrus. After detection of the first standing response on the first day of estrus, only 62 to 82% of sows were detected standing over the next 2 h for all treatments. However, at 4 to 8 h, this increased to 85 to 98% for the AWC and AWP sows, but