Variations in growth pattern and predictablity of liveweight growth of crossred pigs in a tropical wet climate
Four hundred and seventy-six (476) piglets from forty-four (44) farrowings in six (6) breeding cycles obtained from sixteen (16) sows and two (2) mature boars of Landrace, Large White, Hampshire and Duroc crossbred pigs were used to study variations in growth pattern and predictability of liveweight growth. Results obtained from the study showed that only the sow effect factor of the fixed model used was significant (P<0.05) at birth. The results also showed that the sows exhibited good mothering abilities as demonstrated by the linear preweaning (0 – 5 weeks) weight and increased variability in weight from birth (14.46 %) to pre- weaning (49.12 %). At weaning (42 days), a decrease in weight variability (12.63 %) was experienced as a result of weaning stress. This stress imposed a curvilinear growth pattern and highly significant (P<0.001) sow and parity effects factors during the weaner’s phase of growth. Conversely, the changes in ration from weaners to growers with varying levels of crude protein (CP) and metabolizable energy (ME), 20 % CP, 3000 Kcal/kgME and 18 % CP, 2800 Kcal/kgME respectively, gave a linear growth pattern during the grower’s phase. Results of daily rate of gain showed an increasing trend during the pre-weaning phase, a drop during the weaner phase and another increase during the grower’s phase, depicting the self-accelerating growth potentials at the grower phase. The prediction equations results for rate of liveweight growth showed that of the four models used, the quadratic function was the best predictor of liveweight growth, as indicated by the highest and significant R2 value of 90.7 %. This was closely followed by the linear function which had a significant R2 value of 88.1 %. On the other hand, the regression analysis results showed that the linear model recorded the highest “b” (rate of growth) value of 1.275 kg, followed by the quadratic model which recorded a “b” value of 0.465 kg. The results of these growth functions confirmed that linear body measurements were closely related to liveweight, and that body weight can be predicted by age in pigs as both are closely related.
Key words: Growth pattern, predictability, liveweight, crossbred pigs, variations.