Application This study found that on commercial farms in NI the average growth rate of low birth weight pigs was 64g/day lower than that of average birthweight piglets. Furthermore the most common cause of death for low birthweight pigs was starvation and most common stage of death was during lactation. This data will help science and industry at large understand the profile of compromised piglets on commercial farms and lead to strategies to maximise their value. Introduction Increases in litter sizes within commercial pig production have led to elevated numbers of low birthweight pigs with higher pre-weaning mortality, lower weaning weights and reduced lifetime performance (Fix et al, 2010). However an accurate measure of how these animals perform on commercial farms in comparison to heavier littermates in terms of growth performance, mortality and weight at slaughter age using current data is lacking. This study aimed to assess the growth of low and average birthweight piglets from birth to slaughter as well as establish the most common time and cause of death for both weight categories. Material and methods This study followed the performance of 328 low birthweight (Low BW; <1kg) and 292 average birthweight (Av BW; 1.25-1.75kg) piglets across 4 commercial and 1 research farm from birth to slaughter. All farms complied with Red-Tractor Assurance Pig Standards. Normal management practice was not interfered with. Each animal was individually weighed at birth and assigned a numbered ear tag for individual identification. Pigs were weighed at 4, 8, 12, 17 and 22 weeks of age. Parameters of animal origin (e.g. litter size, birth mother) and management (e.g. pen size, diet) were recorded throughout production. All animals which died during the study had a date of death and weight recorded, and all post-weaning mortalities underwent post-mortem analysis. Statistical analysis Data was analysed as a linear mixed model using a REML estimation method. Birth mother parity, number of piglets born alive in each litter, number of still born piglets in each litter, gender, fostering and total litter size were fitted as fixed effects while farm number and birth-mother ID were fitted as random effects. Results Birth mother (BM) parity, born alive (BA) in litter or still born (SB) in litter had no significant effect on performance or mortality (P>0.05). As expected, at weaning Av BW pigs were heavier than Low BW piglets, with a difference of 1.16kg (Table 1). This weight differential increased to 5.74kg by 12 weeks of age and 9.08kg by week 22. Animals which had been cross-fostered were significantly lighter at weaning (7.0kg vs 7.5kg), 8 weeks (17.0kg vs 17.9kg) and 12 weeks (33.kg vs 35.3kg) of age. However this may have been influenced by the majority of cross-fostered animals being of Low BW (57.2% vs 42.8%). Pre-weaning mortality of Low BW pigs was over three times greater than for Av BW pigs, with post-weaning mortality also significantly greater for the Low BW animals. The average age of death was also significantly lower for Low BW pigs. Starvation and sows lying on piglets were the major causes of pre-weaning mortalities in Low BW animals accounting for 49% and 28% of deaths respectively. With Av BW pigs, 30% of pre-weaning mortalities were unknown, with a further 22% of deaths due to over-lying by the sow and 13% caused by scouring. No clear differences were identified in the causes of post-weaning deaths between Low BW or Av BW pigs.
|Publication status||Published - 30 Mar 2020|
|Event||British Society of Animal Science (BSAS) - |
Duration: 30 Mar 2020 → 01 Apr 2020
|Conference||British Society of Animal Science (BSAS)|
|Period||30/03/2020 → 01/04/2020|
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Identifying, understanding and harnessing the beneficial impact of nutritional interactions to optimise the performance and carcass quality of low birth weight pigsAuthor: Hawe, S., Dec 2020
Supervisor: Magowan, E. (Supervisor) & Scollan, N. (Supervisor)
Student thesis: Doctoral Thesis › Doctor of PhilosophyFile