Födelseviktens inverkan på grisars överlevnad, tillväxt och slaktkroppskvalitet

Abstract: To be able to maximize revenue as a pig producer, it is desirable to increase the number of produced animals; both born piglets and slaughtered pigs. The selection for increased litter size has although apparently resulted in an increased amount of piglets weighing <1 kg at birth. The purpose of this study is therefore to investigate how the birth weight of a piglet affects survival, growth until slaughter and carcass quality. The study also elaborates on whether or not the purpose of breeding with the aim of increasing litter size at birth appears to be profitable for the pig producer. Studies has proven that a low birth weight result in impaired survival, vitality, growth and lower weaning weight for those, which make it through the suckling period. In addition, the number of weaned pigs does not seem to be positively correlated to the number of total born piglets. For pigs with a low birth weight, the time between birth and reaching optimal slaughter weight is longer than for a piglet with a normal birth weight, and the relation between meat content and fat content varies between pigs with low and high birth weight. Large litters with a large proportion of pigs with a low birth weight usually require more surveillance and resources such as fostering or support feeding to survive. However, despite these efforts they seem to be unable to reach the same growth rate as pigs with a higher birth weight. Consequently, the profitability of managing such pigs decreases since the expense per pig increases while the revenue stays the same. Therefore, the conclusion is that the birth weight pre-eminently affects a pig’s condition, and that breeding with the aim of an increased number of total piglets born is ineffective in regards to both animal welfare and profitability. A better breeding aim can for instance be homogenous litters with a high proportion of surviving pigs after n days.