RESUMEN
Fixed-time artificial insemination (FTAI) technology uses exogenous reproductive hormones to regulate the sexual cycle and ovulation of sows without oestrus identification, which improves the sow breeding utilisation rate, reduces the number of non-productive days, and elevates the efficiency of pig farm management. In this study, we aimed to optimise FTAI procedures. Healthy 190-day-old and about 90 kg Large White × Landrace crossing breed replacement gilts (n = 166) which were of unknown reproductive status were randomly selected and divided into three groups: a control group (n = 62), an eCG-15D group in which the gilts were pretreated with equine chorionic gonadotropin (eCG) injection 15 days before starting FTAI (n = 50), and an eCG-20D group pretreated with eCG injection 20 days before starting FTAI (n = 54). All three groups were then subjected to the same conventional FTAI procedure. Pigs were orally administered Altrenogest (ALT, 20 mg per pig per day) for 18 days and then 42 h after ALT feeding was stopped, they were injected with 1 000 IU eCG followed by 100 µg GnRH 80 h later. The gilts were inseminated for the first time 24 h after gonadotropin-releasing hormone (GnRH) injection and then again 16 h later. After 42 h of ALT feeding, gilts in the eCG-15D group displayed a higher follicular diameter until artificial insemination (AI) than those from the other groups (P < 0.05). In addition, the ovulation times were the most synchronised in the eCG-15D group, with 100% of the gilts ovulating before the second AI on day 25 of FTAI. Furthermore, the gilts in the eCG-15D group achieved the highest pregnancy rate (92%), farrowing rate (90%), total pigs born (11.59), and pigs born alive (11.18). Together, the findings of this study demonstrate that reproductive performance can be optimised by pretreating gilts with eCG 15 days before conventional FTAI.
Asunto(s)
Inseminación Artificial , Reproducción , Animales , Gonadotropina Coriónica/farmacología , Estro , Femenino , Hormona Liberadora de Gonadotropina , Caballos , Inseminación Artificial/veterinaria , Embarazo , PorcinosRESUMEN
Background: reproductive traits influence lifetime productivity of sows.Objective: to determine the effects of year and season of farrowing, parity number, and breed, on litter size at birth, weaning to service interval (WSI), farrowing to service interval (FSI), and to estimate their repeatabilities. Methods: data from years 1998 to 2008 from a farm in La Piedad, Michoacan, Mexico, were used. Sow breeds were Camborough 22 (PIC), Yorkshire (Y), F1 Landrace x Yorkshire (F1 LY), and ¼ Landrace x ¾ Yorkshire (LY3/4). The studied traits were total pigs born at birth (TPB, n = 45,798), number of pigs born alive (PBA, n = 45,798), WSI (n = 41,156), and FSI (n = 41,156). The statistical model for TPB and PBA included the effects of farrowing year, farrowing season, parity number, breed, and year/season interaction. The model for WSI and FSI included the above factors plus the linear and quadratic effects of lactation length. Results: the overall means for TPB, PBA, WSI, and FSI were 9.31 pigs, 8.60 pigs, 7.87 days, and 29.9 days, respectively. All effects included in the statistical models were significant (p<0.05), except season for TPB and PBA. TPB and PBA increased up to parity 4 and decreased thereafter. The LY3/4 and PIC breed groups had the highest litter size means. The shortest WSI and FSI corresponded to the fall season and the largest to the summer season. WSI and FSI decreased with parity. The Y breed had the shortest and the F1 LY sows had the highest WSI and FSI. The repeatability estimates for TPB, PBA, WSI, and FSI were 0.13, 0.12, 0.14, and 0.14, respectively. Conclusion: year, parity, breed, and lactation length affected litter size, WSI, and FSI. Repeatabilities were low, suggesting that environmental factors are more important than genetic factors for improving the reproductive traits.
Antecedentes: las características reproductivas afectan el tiempo de vida productivo de la cerda. Objetivo: determinar el efecto del año de parto, época de parto, número de parto y grupo racial sobre características de la camada al nacimiento, intervalo destete servicio (WSI), intervalo parto servicio (FSI), y estimar sus repetibilidades. Métodos:se utilizaron los datos de 1998 a 2008 de una granja en La Piedad, Michoacán, México. Las cerdas pertenecían a los grupos raciales Camborough línea 22 (PIC), Yorkshire (Y), F1 Landrace x Yorkshire (F1LY), y ¼ Landrace ¾ x Yorkshire (LY3/4). Las características estudiadas fueron el total de lechones nacidos (TPB, n = 45.798), número de lechones nacidos vivos (PBA, n = 45.798), intervalo destete a servicio (WSI, n = 41.156) e intervalo parto a servicio (FSI, n = 41.156). El modelo estadístico para TPB y PBA incluyó los efectos de año de parto, época de parto, número de parto, grupo racial, y la interacción de año por época. El modelo para WSI y FSI incluyó además los efectos lineal y cuadrático de duración de la lactación. Resultados: las medias para TPB, PBA, WSI y FSI fueron 9,31 lechones, 8,60 lechones, 7,87 días y 29,9 días, respectivamente. Todos los efectos incluidos en los modelos fueron significativos (p<0,05), excepto época para TPB y PBA. TPB y PBA aumentaron hasta el cuarto parto para disminuir posteriormente. Los grupos raciales LY3/4 y PIC tuvieron las mayores medias para tamaño de camada. Los WSI y FSI más cortos correspondieron a la época de otoño. WSI y FSI disminuyeron con el número de parto. La raza Y tuvo los WSI y FSI más cortos y el grupo F1 LY los intervalos más largos. Las repetibilidades para TPB, PBA, WSI y FSI fueron: 0,13, 0,12, 0,14 y 0,14, respectivamente. Conclusión: el año, número de parto, grupo racial y duración de la lactación afectaron los tamaños de camada, WSI y FSI. Las repetibilidades fueron bajas, lo que sugiere que los factores ambientales son más importantes que los factores genéticos cuando se quiere mejorar las características reproductivas.
Antecedentes: as características reprodutivas afetam a produtividade de por vida da porca. Objetivo: determinar o efeito de ano de parto, época de parto, número de parto e grupo racial sobre características da ninhada ao nascimento, intervalo desmama serviço (WSI), intervalo parto serviço (FSI) e estimar suas repetibilidades. Objetivo: o presente trabalho objetivou-se adaptar e validar o método Saraz para determinar o fluxo de NH3 (SMDAE) emitida dos galpões avícolas submetidos à ventilação natural. Métodos: utilizaram-se os dados de 1998 a 2008 de uma granja em La Piedad, Michoacán, México. As porcas pertenciam aos grupos raciais Camborough línea 22 (PIC), Yorkshire (Y), F1 Landrace x Yorkshire (F1 LY) y ¼ Landrace ¾ x Yorkshire (LY3/4). As características estudadas foram o total de leitões nascidos (TPB, n = 45.798), número de leitões nascidos vivos (PBA, n = 45.798), WSI (n = 41.156) e FSI (n = 41.156). O modelo estadístico para TPB e PBA inclui os efeitos de ano de parto, época de parto, número de parto, grupo racial e a interação de ano por época. O modelo para WSI e FSI inclui ademais os efeitos lineais e quadráticos do largo de lactação. Resultados: as medias para TPB, PBA, WSI e FSI foram 9,31 leitões, 8,60 leitões, 7,87 dias e 29,9 dias, respectivamente. Todos os efeitos incluídos em os modelos foram significativos (p<0,05), exceto época para TPB e PBA. TPB e PBA aumentaram hasta o quarto parto para diminuir posteriormente. Os grupos raciais LY3/4 e PIC mostraram as maiores meias para tamanho de ninhada. Os WSI e FSI mais curtos corresponderam má a época de outono. WSI e FSI diminuíam com o número de parto. A raça Y tubo os WSI e FSI mais curtos e os grupo F1LY os intervalos mais largos. As repetibilidades para TPB, PBA, WSI e FSI fórum: 0,13, 0,12, 0,14 e 0,14, respetivamente. Conclusão:o ano, número de parto, grupo racial e largo de lactação afetaram o tamanho de ninhada WSI e FSI. As repetibilidades foram baixas, o que sugere que os fatores ambientais são mais importantes que os fatores genéticos em a melhora das características reprodutivas.