Neonatal split suckling has no impact on pre- and post-weaning piglet growth

Split suckling (SS) is a management technique used when there is a risk that neonatal piglets will not consume adequate amounts of colostrum. The technique involves reducing competition at the udder by removing the larger first-born piglets, thus allowing smaller piglets’ better access to colostrum during and shortly after parturition. Whilst there is evidence that SS improved colostrum ingestion and, subsequently, piglet survival (Vallet 2013), the effects on growth remain to be elucidated. It was hypothesised that split suckling will improve the growth performance of piglets before and after weaning under commercial conditions.

The experiment was conducted at a commercial piggery using parity 0–7 litters (n = 423). Each litter was assigned to one of the following three treatments (n = 141 litters per treatment): control (no SS); rotational (half litter SS hourly for 4 hours, so that each half received 2x1 hour suckling opportunities); or SSam (separation of the largest piglets in a litter, allowing the smallest to suckle for 2 hours in the morning). Prior to fostering on d 0, piglets were tagged and weighed, after which the SS treatments were applied. On d 1, a blood sample was taken from four piglets (two heaviest and two lightest piglets) and used for the estimation of colostrum ingestion (immunocrit technique; quantification of IgG in serum; Vallet et al. 2013). Individual piglets were weighed on d 0 and d 21 relative to farrowing. At weaning, piglets were weaned into treatment group pens (n = 29 pens/treatment; n = 35 pigs/pen), and pen weights were taken on d 0, 10 and 35 relative to weaning. Pre-weaning traits were analysed with a generalised linear mixed model (SAS^®; USA), with birth sow and rearing sow fitted as a random effect. Fixed effects included sex, litter size, sow parity, and SS treatment after adjustment for birth weight. Post-weaning fixed effects included replicate, sex and adjustment for initial pen weight.

During the pre-weaning stage, there was a negative effect of litter size on average daily gain (ADG; P < 0.001). Piglets from gilt litters gained less weight than those from sow litters (Table 1; P < 0.001). There was no effect of SS treatment on the growth of piglets before or after weaning (Table 1; P > 0.05). The SSam piglets tended to grow faster from d 10-35 and 0-35 after weaning, than rotational SS piglets but not from control piglets. Colostrum ingestion (immunocrit) was not affected by treatment or correlated with pre-weaning ADG (r = 0.12 P > 0.05). Under commercial conditions, SS neonatal piglets failed to increase the levels of immunoglobulins unlike those previously reported by Vallet et al. (2013) and hence, piglet ADG both prior to and following weaning was unaffected.

Table 1.  Effects of rotational and SSam split suckling and sow parity on the average daily gain of piglets pre- and post-weaning. Values are mean (± SEM)