Piglet birth weight, subsequent performance, carcass traits and pork quality: A meta-analytical study

The meta-analyses were carried out to study the effect of piglet birth weight on performance, carcass traits and pork quality. The database totaled 3294 piglets (28 articles published from 2000 to 2014). The piglets' mean weight at birth was 1.45 kg. The weights were classified into three groups: heavy (average weight 1.80 kg), medium (1.48 kg) and light (1.09 kg). The publications selected for the meta-analyses presented results from experiments with at least two weight ranges at birth and organ weight and/or performance and/or carcass data. The piglets' body and organ birth weights showed highly significant and positive correlations (P < 0.05); piglets of low birth weight also had (P < 0.05) light weight organs. The piglets' birth weight was positively correlated (P < 0.05) with their body weight and weight gain in the all subsequent stages of production. Heavy piglets at birth were 6.6 kg heavier (P < 0.05) at slaughter (150 days of age) compared to light-born piglets. The age at which the piglets reached 110 kg body weight was (P < 0.05) 9.5 days in those born with medium and high weights, and 12.1 days in those born with light weight. Light weight piglets presented a relative belly weight at slaughter 0.5% higher (P < 0.05) than piglets with high birth weight. At slaughter, the weight of the ham of heavy-born piglets was (P < 0.05) 4.4% higher, and the heart and liver weight was (P < 0.05) 6.8% higher than those of light weight piglets; however, the other pork quality were not influenced (P < 0.05). The birth weight of piglets influences performance and in overall does not alter pork quality. However, when piglet weight at birth is greater than 1.50 kg performance is not influenced.