Effects of space allocation on finishing pig growth performance and carcass characteristics1

A total of 405 pigs (PIC 327 × 1,050) were used in 2 experiments (Exp. 1, initially 66.1 ± 1.8 kg BW, Exp. 2 initially 60.8 ± 2.5 kg BW) to examine the effects of space allocation on finishing pig growth performance and carcass characteristics. Pigs were randomly allotted to pens on entry into the finishing facility. Pens of pigs were balanced by initial BW and randomly allotted to 1 of 3 treatments with either 7 or 8 replications per treatment (Exp.1 and 2, respectively). There were 9 pigs per pen and gates were adjusted to provide 0.84, 0.74, or 0.65 m2 per pig. Each pen was equipped with a dry single-sided feeder with two 35.6 cm × 11.4 cm (length × width) feeder spaces and a cup waterer. In both experiments, as space allocation decreased, overall ADG and ADFI decreased (linear, P < 0.019) with no evidence for differences in G:F. In Exp. 2, there was marginal evidence for a linear improvement (P = 0.061) in G:F as space allocation decreased from d 42 to 56. Final BW was 3.8 and 5.3 kg greater (linear, P ≤ 0.005) in Exp. 1 and 2, respectively, when comparing the 0.65 to the 0.84 m2 per pig space allocation treatments. Using a predicted k-value of 0.0336, ADFI and, subsequently, ADG should have begun to decrease when pigs reached 121.2, 101.7, and 83.3 kg at 0.84, 0.74, or 0.65 m2 per pig, respectively. In Exp. 1, we found marginal evidence for a reduction in ADFI as space allocation decreased starting at a mean BW of 80.3 kg (d 14; linear, P = 0.072). In Exp. 2, ADFI and consequently ADG decreased linearly (P < 0.029) starting at a mean BW of 74 kg, as space allocation decreased, before pigs reached the k-value that should have influenced performance. It is unknown if growth performance was impacted for the 0.84 m2 treatment group as this was the greatest space allocation treatment. Overall, these studies indicate that decreasing space allocation resulted in poorer ADG driven by a reduction in ADFI. The data suggests that the accepted k-value of 0.0336 might underestimate the impact of space restriction on finishing pig ADG and ADFI.

Effect of stocking rate on pig performance in a wean-to-finish production system

Crossbred pigs (n = 1,296) were used in a randomized complete block design to evaluate three stocking rate treatments (22, 27, or 32 pigs pen-1) on growth performance from weaning [5.0 ± 0.01 kg body weight (BW); 15 ± 1 d of age] to 24 wk post-weaning. Floor and feeder spaces per pig were 0.78 m2 and 4.2 cm, 0.64 m2 and 3.4 cm, and 0.54 m2 and 2.9 cm for group sizes of 22, 27, and 32, respectively. During the first 8 wk postweaning there was a tendency for average daily gain (ADG) (511, 505, and 497 g d-1, respectively; P = 0.07) and BW (35.1, 34.7, and 34.3 kg, respectively; P = 0.08) to decrease linearly as stocking rate increased. Moreover, from week 8 to 18, week 18 to 24, and for the overall period (weaning to week 24) both ADG (688, 660, and 635 g d-1 for the overall period, respectively) and BW (121.8, 117.1 and 113.1 kg at week 24, respectively) decreased linearly (P < 0.001) with increasing stocking rate. There were no treatment differences in the coefficient of variation in pig BW within a pen at any stage of the study. Morbidity and mortality rates increased linearly (8.5, 10.2, and 12.7%; P < 0.05) with increasing stocking rate. In conclusion, decreasing group size, thereby increasing floor and feeder space pig-1, reduced morbidity and mortality and increased growth rate after 8 wk post-weaning resulting in heavier pigs at 24 wk post-weaning for the smaller groups. Key words: Pigs, stocking rate, weaning, finishing

Effects of group size and feeder space allowance on welfare in finishing pigs

Compared with small groups, housing in large groups offers the pig more total available space, resulting potentially in an increased degree of control over its (micro) environment. For the producer, large groups require fewer pen divisions and offer more possibilities for the sharing of resources such as feeders and drinkers. However, whilst large groups may offer benefits to higher ranking animals in the group, there may be serious disadvantages for those further down the social hierarchy, who also need to compete for access to resources. This study investigated the interactive effects on welfare of food availability (one single space hopper per 20 or per 10 pigs) and group size (20, 40 or 80 pigs per pen), at constant stocking density (0·55 m2per pig) in part-slatted pens. Groups provided with two feeding spaces per 20 pigs were less active than groups with one feeding space per 20 pigs. The number of aggressive interactions per pig at the food trough was not affected by group size but decreased with number of feeder spaces per 20 pigs. The number of skin lesions increased with group size. Average daily gain in the first half of the finishing period was negatively influenced by group size and positively by number of feeding spaces. No effect on weight gain was found subsequently. Within-group variation in growth was not affected by group size or number of feeder spaces. No differences between treatments were found in the number of pigs removed for health reasons. Interactive effects of the two treatments were found on some behaviours but not on any of the performance variables measured. It is concluded that, from a welfare point of view, the number of pigs per feeder space should be lower than 20, although performance levels appear acceptable at 20 pigs per feeder. Further research will have to identify whether the effects of group size on general aggression is common to all finishing pig systems, or whether the presence of straw can serve as a mitigating factor.

RESPONSE OF BROILERS TO VARIATIONS IN WATERER, FEEDER, AND FLOOR SPACE UNDER CONTINUOUS AND INTERMITTENT PHOTOPERIODS

The effects on broiler performance of different floor, waterer, and feeder spaces and light treatments were estimated. Increased bird density resulted in a reduction in body weight, poorer feed conversion, reduced carcass quality and a reduction in monetary returns per bird started. Feeder space effects were inconsistent. Waterer spaces examined had little effect on bird performance. Light treatments studied revealed that cycles of 1 h of light with 3 h of darkness resulted in slightly superior feed conversion compared with cycles of 3 h of light and 1 h of darkness.