Effects of physical or fenceline boar exposure and exogenous gonadotropins on puberty induction and subsequent fertility in gilts

Abstract

The present study was part of a larger experiment that evaluated litter of origin effects on gilt production. The objectives of this study were to determine the effect of physical or fenceline boar exposure and exogenous gonadotropins on puberty induction and subsequent fertility in a commercial farm environment. The experiment was performed in three replicates. Prepubertal gilts were assigned by pen (13/pen) to receive 15 min of daily Fenceline (FBE, n = 153) or Physical (PBE, n = 154) Boar Exposure (BE) for 3 weeks starting at 184 d of age in a purpose-designed Boar Exposure Area (BEAR). At the start of week 3, prepubertal gilts were randomly assigned to receive PG600 or none (Control). From weeks 4 to 6, estrus was checked using only FBE. During weeks 1 to 3, measures of reproductive status were obtained weekly or until expression of estrus. Upon detection of first estrus, gilts were relocated into stalls and inseminated at second estrus. PBE reduced age (P = 0.001) and days to puberty (P = 0.002), increased the proportion of gilts in estrus (P = 0.04) in week 1 (38.3 vs. 27.5%), and tended (P = 0.08) to improve estrus in week 2 (37.6 vs. 26.1%) compared to FBE, respectively. In week 3, more prepubertal gilts receiving PBE-PG600 exhibited estrus (P = 0.04; 81.8%) compared to PBE-Control (40.3%), FBE-PG600 (56.4%), and FBE-Control (47.8%). Overall, expression of estrus through week 6 tended (P = 0.08) to be greater for PBE than FBE (91.5 vs. 85.0%). PBE increased (P ≤ 0.05) or tended to increase (P > 0.05 and ≤0.10) service and farrowing rates in parities 1 through 4, but within parity, there were no effects (P > 0.10) on pig production or wean to service interval. Analyses also indicated that weeks from start of boar exposure to puberty, litter of origin traits, and follicle measures at puberty were related to the subsequent fertility. The results of this study confirm the advantages of using increased intensity of boar exposure, combined with PG600 treatment, for effective induction of pubertal estrus in a commercial setting.

Functional genomics of reproduction in pigs: Are we there yet?

“…Nonetheless, swine genetic companies have embraced the use of SNP markers for genomic selection and are typically genotyping animals at a far greater scale than is achievable in small academic research herds. Commercial‐academic partnerships have become increasingly common for understanding physiological and management factors related to pig reproduction (Díaz et al, 2017, Knox et al, 2021; Lents, Lindo, et al, 2020; Lents, Supakorn, et al, 2020; J. Patterson et al, 2020). Extending these types of partnerships to genotypes and genomic sequencing will be vital for identifying functional variants interacting with physiology, management, and environment in pork production.…”

Managing Reproduction in Hyperprolific Sow Herds

“…An adequate puberty stimulation process is essential to provide a consistent supply of eligible gilts for service [9]. The occurrence of puberty can be stimulated at younger ages by several environmental and management factors [12,13], but attempts to associate puberty with a critical weight [14,15], growth rate (GR) [16], fat [14,17], or lean tissue [17] are still controversial, being strongly influenced by the genotype.…”

Managing prolific sows in tropical environments

“…Puberty attainment in gilts can be affected by numerous management factors including housing, climatic environment, season, manure handling systems, feeding systems, nutrition programs, health, and boar exposure (Knox et al, 2021; Levis, 2000; Sankarganesh et al, 2021; Tummaruk, 2012; Tummaruk et al, 2004). Other key factors that may affect puberty onset in gilts are litter of origin, birth weight, growth rate, and body composition (Knox, 2019; Patterson et al, 2020; J. Patterson & Foxcroft, 2019; Tummaruk, Tantasuparuk et al, 2009).…”

“…At first estrus, the body weight and the backfat thickness of gilts averaged 106 kg and 13.0 mm, respectively (Tummaruk et al, 2007). In temperate areas, gilts normally enter in the gilt pools at about 100 days of age and exit at about 226 days of age (Knox et al, 2021). In Thailand, replacement gilts normally enter the gilt pools at about 174 days of age (92 kg) and exit at about 226 day of age (131 kg) (Tummaruk, 2012).…”