A.D. Beaulieu of the Prairie Swine Centre and colleagues there and with Agriculture and Agri-Food Canada and PIC have recently published a paper in Journal of Animal Science. The objective of the study, they explain, was to investigate the relationships between birth weight, birth order or litter size on growth performance, carcass quality and eating quality of the ultimate pork product.

They collected data from 98 pig litters and, with the addition of recording birth weight and birth order, farrowing and piglet management were according to normal barn practices.

In the nursery and during grow-out, the pigs received the normal feeding programme for the barn and, with the addition of individual tattooing, were marketed as per standard procedure. From 24 litters, selected because they had at least 12 pigs born alive and represented a range of birth weights, four piglets were chosen (for a total of 96 piglets) and sent to Agriculture and Agri-Food Canada-Lacombe Research Centre (Lacombe, Alberta, Canada) when they reached 120kg for extensive meat quality and sensory analysis.

Individual bodyweight (BW) was measured at birth, on the day of weaning, five weeks after weaning, at nursery exit, at first pull and at the time of marketing.

Litter sizes were divided into three categories: small (3 to 10 piglets), medium (11 to 13 piglets) and large (14 to 19 piglets).

There were four birth-weight quartiles: 0.80 to 1.20, 1.25 to 1.45, 1.50 to 1.70, and 1.75 to 2.50kg.

Increased litter size resulted in reduced mean birth weight (P<0.05) but had no effect on within litter variability or carcass quality (P>0.05) when slaughtered at the same end-point.

Lighter birth-weight pigs had reduced BW at weaning, five and seven weeks post-weaning, and at first pull and had increased days to market (P<0.05).

Birth weight had limited effects on carcass quality, weight of primal cuts, objective quality and overall palatability of the meat at the same slaughter weight (P>0.05).

Beaulieu and co-authors concluded that increased litter size resulted in decreased mean birth weight but no change in days to market. Lighter birth-weight pigs took longer to reach market. Despite some differences in histological properties, birth weight had limited effects on carcass composition or final eating quality of the pork when slaughtered at the same BW, and large litter size resulted in more pigs weaned and marketed than the smaller litters.

They added that, under the conditions of this study, other than increased days to market, there is no reason based on pig performance or pork quality to slow down the goal of the pork industry to increase sow productivity as a means to increase efficiency.

Reference

Beaulieu A.D., J.L. Aalhus, N.H. Williams and J. F. Patience. 2010. Impact of piglet birth weight, birth order, and litter size on subsequent growth performance, carcass quality, muscle composition, and eating quality of pork. J. Anim Sci. 2010. 88:2767-2778. doi:10.2527/jas.2009-2222.

Further Reading

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You can view the full report (fee payable) by clicking here.