Influence of lactation length and gonadotrophins administered at weaning on fertility of primiparous sows

Consistency is key: interactions of current and previous farrowing system on litter size and piglet mortality

“…For example, voluntary feed intake of sows is sometimes higher in free farrowing than crated systems (Cronin et al, 2000), whilst sows housed in nonrestrictive systems exhibit more control over nursing behaviour (Arey and Sancha, 1996;Thodberg et al, 2002b), and therefore may begin weaning the litter and reducing metabolic demand before on-farm weaning occurs. In the current study, increasing first parity lactation length also tended to increase second parity litter size, which has been found previously and postulated to result from an improved metabolic status at service (Hidalgo et al 2014).…”

Use of chorionic gonadotropins during lactation to optimize postpartum sow reproductive performance: a review

“…Those disorders may be frequent in primiparous sows, characterizing the second parity syndrome ( Kemp et al, 2018 ), since primiparous sows may still need to achieve their adult weight and may have lower energy body reserves compared to multiparous sows ( Hoving et al, 2012 ). Additionally, negative energy balance may be aggravated during periods of high environmental temperatures, in which the feed intake may be reduced ( Rabelo et al, 2016 ), particularly in some hyper prolific genetic lineages ( Hidalgo et al, 2014 ).…”

“…Eventually, performing AI on the first estrus after weaning may be related to negative effects on the subsequent reproductive performance, resulting in increased embryo resorption rate and reduction in farrowing rate and litter size, as occurs when lactational catabolism is excessive, or after early weaning at periods shorter than 21 d ( Levis, 1997 ; Zemitis et al, 2015 ). That may be avoided by skipping the first post-weaning estrus, allowing weaned sows to have more time to restore their body condition, and conducting AI at the second estrus after weaning ( Hidalgo et al, 2014 ; Kemp et al, 2018 ). Nonetheless, the number of non-productive days added by such practice would correspond to the duration of an additional estrous cycle, which would impair the herd's reproductive efficiency ( Dial et al, 1992 ).…”

Estrategias en el manejo reproductivo de la cerda para la mejora de la fertilidad = Reproductive management strategies for improving sow fertility

“…Las restantes 8 cerdas primíparas fueron sacrificadas por causas no reproductivas antes de concluir el periodo de lactación. Los detalles del manejo de las cerdas primíparas ya han sido previamente indicados dentro de este capítulo, durante el desarrollo metodológico llevado a cabo en el segundo experimento de la Tesis Doctoral (Hidalgo et al, 2014b). De forma resumida, después de 3 semanas de lactación, las cerdas primíparas fueron asignadas aleatoriamente a uno de cuatro tratamientos: 1) W3 (n = 165); destete a los 21 días de lactación, sin administración de PG600 ® al destete, 2) W5 (n = 103); destete de la camada original a los 21 días de lactación y transferencia inmediata de una segunda camada de lechones con 7 días de edad para una lactancia adicional de 2 semanas, sin administración de PG600 ® al destete final después de 5 semanas de lactación, 3) W3+P (n = 108); destete a los 21 días de lactación y administración de una inyección IM (5 mL) de PG600 ® al destete, y 4) W5+P (n = 96); destete de la camada original a los 21 días de lactación y transferencia inmediata de una segunda camada de lechones con 7 días de edad para una lactancia adicional de 2 semanas, con administración de una inyección IM (5 mL…”