Large pellets in creep feeding improve performance of newly-weaned piglets

Saturday, January 31, 2015

Dutch research suggests that it is advisable to provide suckling piglets with creep feed in the form of a large pellet early in lactation – not for its nutritive value, but to stimulate early feed intake

by JANICE MURPHY

There is no doubt about it, weaning is stressful. Often associated with reduced nutrient intake, poor growth rate or even weight loss in piglets, weaning can have a significant impact on health and performance as piglets adjust to a completely new environment away from the sow. Without adequate nutrients, the structure and function of the intestinal tract is severely impaired, resulting in digestive upset, poor performance and increased susceptibility to disease.

Previous studies have proven that creep feed intake during the suckling period has a positive influence on early post-weaning feed intake and performance of piglets. However, the consumption rate of creep feed is often poor and can be quite variable between and within litters. In an attempt to stimulate feed intake in suckling piglets, most studies have focused on feed composition, rather than the potential impact of physical feed characteristics.

Commercial pellet sizes for piglet creep feed typically run in the neighborhood of three millimetres or less, following the general belief that smaller diameter pellets will encourage feed intake in young animals. However, larger feed particles would be considered common in nature. One study showed that five-millimetre diameter pellets and feed in the form of large sow rolls resulted in more feeder-directed exploratory behaviour compared to feed with a smaller size. To date, preference of piglets during lactation for either small or large pellet size, and the subsequent effects on feed intake post-weaning, had not been investigated.

Researchers at Wageningen University in the Netherlands recently set out to investigate piglets' preference for large or small feed pellets, and the effects of pellet diameter on feed intake, feed-related behaviours and growth of piglets during and after lactation.

Three experiments were carried out, featuring pellets differing in diameter. In experiment 1, 19 litters were provided with pellets of two and 12 millimetres in diameter from day 4 of lactation onward. In experiment 2, 39 litters were provided with creep feed of either two-millimetre or 10-millimetre pellets from day 3 of lactation onward. Experiment 3 was a two-by-two factorial design where 18 litters were provided creep feed during lactation of either two or 12 millimetres in pellet diameter. At weaning, each litter was then split into two comparable half litters and each of these half litters was provided with feed of two or 12 millimetres in diameter.

In experiment 1, from day 4 to 18, piglets significantly preferred the 12-millimetre pellets over the two-millimetre pellets, consuming 519 grams per pen compared to 168 grams per pen. This result was repeated in experiment 2, where feed intake from day 3 to 17 was significantly higher in litters given the 10-millimetre pellets rather than the two-millimetre ones (1,752 vs. 1,101 grams per pen). Despite this difference in intake, piglet body weight at weaning did not differ between treatments.

There was, however, an interaction between treatment and day of lactation in the amount of time spent on eating-related behaviours. Time spent eating and interest in eating increased as lactation progressed, but this increase was lower in the litters provided with the larger diameter pellet. Time spent suckling remained the same in litters provided with smaller diameter pellets, but decreased over time in litters provided the larger diameter pellets.

In experiment 3, feed intake was significantly higher in the 12-millimetre pellet litters than in the two-millimetre ones from day 4 to 11 of lactation (Table 1). Pellet diameter provided after weaning did not affect body weight gain or feed intake. Piglets provided the 12-millimetre pellets before weaning, however, had a significantly higher body weight gain (2,060 versus 2,606 grams per pig) and feed intake (2,772 versus 3,173 grams per pig) and a lower feed conversion ratio between day 0 and 10 after weaning than piglets provided the two-millimetre pellets before weaning (Table 1).

Behaviour of the piglets after weaning was not affected by pellet diameter pre- or post-weaning. Regardless of treatment, feed exploration, drinking and manipulation of other piglets significantly decreased between day 2 and 8 after weaning, while playing, belly nosing and mounting significantly increased in the same time period.

This unique set of experiments demonstrated that, given the choice, piglets prefer creep feed with a large diameter (10-12 millimetres) above feed, identical in composition, with a small diameter (two millimetres).

When provided with larger pellets, these young piglets showed more interest in the feeder, in line with previous studies, particularly in the early stages of lactation. Moreover, in all three experiments, piglets consumed more of the large pellets during the first week or two of lactation. That was in spite of the fact that the hardness (measured in kilograms) of the larger pellets was significantly higher (7.8 kilograms for the 12-millimetre versus 0.8 kilograms for the two-millimetre diameter pellets in experiment 1; 13.9 kilograms for the 10-millimetre versus 5.5 kilograms for the two millimetre diameter pellets in experiment 2).

An additional benefit of larger diameter pellets is that they cannot pass as easily through the slats and drop into the manure pit. As a result, the higher intake of the larger pellets during early lactation is not due to a higher wastage, and may even reflect an underestimate as the smaller pellets could more easily be wasted.

The researchers speculated that the large pellets may have encouraged earlier feed-related exploration and feeding for a number of reasons. They may have stimulated exploratory behaviour since they could be more easily manipulated on the floor, given that it would be more difficult for them to pass through the slats. While gathering behavioural data, young piglets were observed moving large pellets around and picking them up from the floor, perhaps playing a role in initiating independent feeding.

As part of the weaning process, changes in muscle, bone and teeth growth occur that are necessary for piglets to adapt to independent feeding. It is possible that larger pellets might be easier to handle and ingest because of the immature jaw muscles and oral movements of young piglets, meanwhile facilitating teething, much like a teething ring for children. The eruption of premolars in young piglets would also have considerable impact on feeding behaviour and feed intake.

During the last two weeks of lactation the preference for the large pellets waned, suggesting that once piglets start eating they are no longer concerned with feed size, having mastered the necessary mechanics for handling and consuming solid feed.

In experiment 3, the higher feed intake of the 12-millimetre pellets early in lactation also positively affected post-weaning performance. Besides the positive impact on behaviour and motor skills needed for independent feeding, ingestion of solid feed may influence the maturity of the gastrointestinal tract and activation of digestive enzymes. The experience of confidently consuming solid feed prior to weaning would also be an important asset to increase the acceptance and intake of solid feed post weaning.

After weaning, many piglets suffer from low feed intake and, as a consequence, a depression in growth and higher incidence of diarrhea. Experience with eating solid feed during the suckling period will prepare the piglet, both behaviourally and physiologically, for the post-weaning diet. Looking at the lactation period as a whole, feed intake was not significantly different between piglets provided the small or large diameter pellets; the larger pellet only promoted the feed intake very early in lactation when feed intake was still low. Yet, pre-weaning pellet size profoundly increased body weight gain and feed intake post-weaning. This suggests that encouraging solid feed consumption, despite being low and probably nutritionally negligible, may be important to prepare piglets better to cope with the transition at weaning from sow's milk to a solid diet.

Based on these results, it is advisable to provide suckling piglets with creep feed in the form of a large pellet early in lactation, not for its nutritive value, but to stimulate early feed intake. BP

Janice Murphy is a former Ontario agriculture ministry swine nutritionist who now lives and works in Prince Edward Island.

Source: H. van den Brand, D. Wamsteeker, M. Oostindjer, L.C.M. van Enckevort, A.F.B. van der Poel, B. Kemp and J.E. Bolhuis. 2014. Effects of pellet diameter during and after lactation on feed intake of piglets pre- and post-weaning, J ANIM SCI (published ahead of print July 1, 2014, doi:10.2527/jas.2013-7408).