South African Journal of Animal Science
On-line version ISSN 2221-4062
Print version ISSN 0375-1589
STEYN, W.J.; CASEY, N.H. and JANSEN VAN RENSBURG, C.. Effects of different penning conditions, feeding regimens and season on growth and carcass attributes of boars of a selected genetic line. S. Afr. j. anim. sci. [online]. 2012, vol.42, n.2, pp.178-188. ISSN 2221-4062.
The study tested the performance of intact male pigs from a selected genetic line subjected to differing feeding regimens and penning conditions. The trial was a 2 x 3 x 2 x 3 factorial design, consisting of winter and summer periods, three sire lines, two diets and three feeding regimens. The pigs were intact males grown over three phases, starter (25 to 50 kg); grower (51 to 80 kg) and finisher (81 to 105 kg).The pigs were randomly allocated to three feeding regimens, a controlled single feeding, ad libitum single feeding and ad libitum group feeding, with six animals per ad libitum group. This resulted in 96 pigs in six treatments with six replicates. The diets were high (HF) and low (LF) nutrient dense feeds, where the LF was 95% of the HF. Season affected growth; the winter animals had a significantly greater growth response, end-mass and average daily gain (ADG). The HF diet resulted in significant improved ADG, feed conversion ratio and protein deposition rate, especially during summer. However, end-mass, ADG and average protein deposition rates of controlled-fed pigs were significantly lower compared to the ad libitum group and single-fed animals. The hypothesis was affirmed that high-performing intact male pigs are sensitive to and affected by feeding regimens and penning conditions that will affect their production.
Keywords : Protein and lipid deposition; growth performance; ad libitum versus restricted feeding.