Periódicos Brasileiros em Medicina Veterinária e Zootecnia

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Impact of the birth weight of landrace x large white dam line gilts on mortality, culling and growth performance until selection for breeding herd

Magnabosco, DiogoCunha, Evandro César PereiraBernardi, Mari LourdesWentz, IvoBortolozzo, Fernando Pandolfo

Background: Piglets weighing less than 1 kg have become a common occurrence in pig farms due to selection for increasing litter size. Large litters imply a decrease in the mean piglet birth weight and an increase in the within-litter variability of birth weight with a greater risk of mortality and lower growth performance. The aim of this study was to evaluate the effects of birth weight of female piglets on growth performance and on removal rates until selection for entry into the breeding herd (170 days) of Landrace x Large White crossbred gilts.Materials, Methods & Results: A total of 1495 Landrace x Large White (DB 25® - DanBred) crossbred female piglets were individually weighed after birth (BiW) and housed on the same farm from birth onwards. During the following developmental stages, gilts were again individually weighed: at 10 days, at weaning, nursery, rearing and selection (170 days). A phenotypic evaluation was performed to select the gilts that would be included in the breeding herd. Predicted probabilities for mortality, according to BiW, were estimated using logistic regression models. Female piglets were also retrospectively classified into eight classes of BiW based on percentiles, i.e., approximately 12.5% in each group. Cumulative losses by death or removal until weaning, nursery and selection phase were analysed using logistic regression models. The ability of pigs to compensate for low BiW was estimated using the percentages of gilts that changed at least one body weight (BW) category from birth to 170 days of age. For this purpose, eight classes of BW at 170 days were also created. BW and average daily weight gain (ADWG) were analysed as repeated measures. Overall, the mean BiW of the female piglets was 1387.8 ± 8.8 g, with a coefficient of variation of 24.4%. The removal rate until 170 days was 27.0% (403/1495) and locomotion problems were the major cause of culling (16.4%).[...](AU)

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