Litter size, parity and sex effects on weaning and post weaning growth of pigs

Abstract

Pig breeding has been mostly affected by number of piglets that survived to market age with regards to their productivity and fitness traits. This study investigated the influence of sex, parity and litter size on three growth performance characteristics (weaning weight, total weight gain and average daily gain of piglets) at the weaning and post-weaning period of piglets. The 43 piglets investigated are from the cross of Camborough and Landrace breeds, comprising 25 male and 18 female piglets, from three different parities and five unique litter sizes. Measurements of body weight of the piglets were taken immediately at weaning and consistently for additional 12 weeks on a regular weekly basis. The piglets were tagged with an ID and restrained for the measurement, which was recorded against each piglet ID. All measurements were done with a digital hanging balance sensitive to 0.00g, whereby the piglets were placed in bags and hung for weighing. Data collected were recorded on excel worksheets and validated for precision and accuracy. Preliminary descriptive statistics was done to check the data for normality, and indices (total weight gain and average daily gain) were computed from the measured weekly values. The values ranged between 3.55kg-8.35kg, 6.90kg-18.45kg and 0.08kg-0.22kg respectively for weaning weight, total weight gain and average daily gain. Sex did not exert significant (P>0.05) influence on any of the three characteristics studied, while parity only significantly (P<0.05) impacted weaning weight but did not influence the other two parameters (total weight gain and average daily gain). However, litter size significantly affected the three parameters investigated with the largest influence recorded on weaning weight (61.1%). The relationship between weaning weight and subsequent weekly weights were mostly positive (direct) and significant, with the exception of Week 1 post weaning that was negative. The study revealed that piglets from small to moderate litter sizes tend to have higher post weaning weights