REGULAR ARTICLES The effects of breed, season and parity on the reproductive performance of pigs reared under hot and humid environments J. K. Hagan 1 & N. N. Etim 2 Received: 12 April 2018 /Accepted: 30 August 2018 # Springer Nature B.V. 2018 Abstract A research aimed at evaluating the reproductive performance of pigs as influenced by breed, season, and parity was carried out. Reproductive performance records of 1383 sows made up of 204 primiparous and 1179 multiparous large white (687) and Duroc × large white crosses (696) obtained over a 3-year period (2013 to 2016) were used. Data on reproductive performance taken were farrowing rate, litter size at birth and at weaning, piglet weight at birth and at weaning farrowing interval and pre-weaning mortality. To determine the effect of season, parity and breed on reproductive performance, the 4-way analysis of variance (ANOVA) was used. A mixed model was fitted using the generalized linear model (GLM) procedure of the GenStat (Discovery Edition) to investigate the fixed effects of breed (two classes), season of birth (three classes) and parity (five classes) on the reproductive traits. Where differences in means were observed, the means were separated using the least significant difference at 5% level of significance. Results obtained indicated litter size at birth of 12.5 ± 0.3 and 14.2 ± 0.5 for the large white and the Duroc × large white respectively and farrowing rates of 90.0 ± 2.3 and 94.5 ± 2.5% for the large white and the Duroc × large white respectively. Litter size at birth and at weaning, farrowing rate and piglet weight at birth were all influenced by parity and season with increasing parity significantly reducing litter size at birth and at weaning. Reproductive traits of the sows were superior during the rainy season, an indication of the need to consider season of birth in making decision. Keywords Large white . Duroc . Litter size . Season . Parity and breed Introduction In Ghana, pig production is practiced mainly by intensive and extensive smallholder farmers under small-, medium- and large-scale commercial enterprises (MoFA 2012) with the prominent breeds reared being the large white (LW). The large white breeds are noted for their desirable reproductive poten- tial. To ensure improved efficiency in pig production, growth and reproductive traits are important economic traits which need much attention. According to Patterson et al. (2010), sows are capable of raising an average of 30–40 piglets annu- ally, hence the need to study the reproductive performance of sows under different environments. Again, the reproductive performance of breeding sows, according to Rekwot et al. (2001), could influence the efficiency of swine production, with high reproductive performance being considered to be of economic significance to the pig industry. Farrowing rate, litter size at birth and at weaning and fertility index are among the primary parameters used to measure the reproductive per- formance of female pigs (Yilma 2017). These important re- productive traits could be influenced by season, parity, breed, lactation length and nutrition (Bloemhof et al. 2008). Whereas the last two factors can be controlled, season, parity and breed could be difficult to control because they directly affect the volume of production. It is therefore important to perform a detailed analysis on how these could impact on performance. Season of farrowing can directly affect the reproductive per- formance of pigs (Love et al. 1993) by directly impacting on the litter size and piglet survival after birth (Tummaruk et al. 2010). Additionally, it may affect results in the rearing of piglets, for example due to heat stress and feed intake during lactation. Temperature variation and photoperiodic reaction during a season are considered the main causes influencing * J. K. Hagan jhagan1@ucc.edu.gh 1 Department of Animal Science, University of Cape Coast, Cape Coast, Ghana 2 Department of Animal Science, Obio Akpa Campus, Akwa Ibom State University, Obio Akpa, Akwa Ibom State, Nigeria Tropical Animal Health and Production https://doi.org/10.1007/s11250-018-1705-5