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Variable creep feed intake confounds trial results

The benefits of creep feeding are notoriously variable, with some research trials showing a positive benefit and others showing no advantage. Even taking into account factors such as weaning age, length of the creep-feeding period, and type of diet fed, it is somewhat of a mystery why the outcomes are not more consistent. So what’s the latest on this topic?

Work published last year by the Prairie Swine Centre (PSC) found no benefit. Pigs provided with creep feed for seven days prior to weaning were not heavier at weaning and, perhaps surprisingly, this was true for both the heaviest and the lightest pigs in the litter.

“Moreover, this data showed that piglets from litters offered creep were less inclined to visit the feeder in the nursery immediately post-weaning,” said researcher Denise Beaulieu. “This implies that there were no behavioural benefits from the early introduction of solid feed.”

This latest research indicates variability in results is likely due to differences in feed intake between individual pigs. A recent trial involving 100 litters used creep feed containing a non-toxic dye so individual pigs that ate creep could be identified by taking anal swabs. Similar to the previous work, on average, litters fed creep did not have a higher daily gain from 21 days of age, when creep feeding commenced, until weaning. Nor did they show improved growth rate during the early nursery stage. However, results for individual pigs had some differences.

“Approximately 37 per cent of piglets offered creep showed evidence of consumption after five days,” said Beaulieu.

“Within the creep ‘eaters,’ 45 per cent had evidence of consuming the Phase 1 diet when swabs were taken 48 hours after weaning. Within the creep ‘non-eaters,’ this figure was 55 per cent.” This, she said, corroborates a previous experiment where video tape observations showed piglets from litters offered creep had fewer “feeder approaches” during the first 24 hours post-weaning. Growth rate during the first three days post-weaning, of piglets classified as “creep and nursery eaters” was improved relative to other groups. Moreover, according to Beaulieu, there is evidence this improvement was maintained throughout the nursery period.

“Creep feeding improves weaning and nursery exit weights for those piglets which actually consume feed,” she said. “Further work is required to determine why not all piglets consume the creep feed and whether these piglets will show improvements in growth if they can be encouraged to consume the creep feed.”

Can we feed according to growth potential?

During the grow-finish period, variability in the response of individual pigs and groups of pigs makes defining their nutritional requirements a challenge. Even when pigs are penned according to size, and diets fed according to weight, variability is still high. In practice, we tend to feed a better-quality diet than we need to, in order to meet the needs of the smaller and slower-growing pigs. But what if we could categorize pigs according to their growth potential and feed them accordingly? A PSC trial looked at whether early growth rate is predictive of the efficiency of energy utilization later in life.

Sixty barrows were assigned to either a slow, average or fast potential growth rate (PGR) group on the basis of their growth from birth to 30 kilograms, then fed either a low- or a high-energy diet.

“The slow-growing pigs were about 98 days of age, almost four weeks older than the fastest-growing pigs, which reached 30 kilograms at only 71 days of age,” said Beaulieu. “The average PGR group was 78 days of age.”

Despite the differences in growth rate to 30 kilograms, daily gain from 30 to 60 kilograms was only slightly higher for the fast PGR pigs. Also, energy concentration of the diet had no effect on growth rate — feed intake was reduced on the high-energy diet, therefore feed efficiency was improved for pigs fed this diet.

“The pigs were slaughtered when they reached 60 kilograms, then the carcasses ground and analyzed for nutrient content,” said Beaulieu. “Comparing the data with a group of pigs slaughtered at the beginning of each experiment allows the calculation of nutrient retention within each growth period.”

The efficiency of utilization of energy for growth, protein or lipid deposition was numerically lower for the fast-growing pigs relative to the average or slower-growing pigs, however, this difference was not significant.

“The efficiency of energy utilization for protein or lipid deposition was improved with the low-energy diet,” said Beaulieu. “Also, pigs fed the diet at 85 per cent of ad libitum intake utilized energy more efficiently relative to those allowed 100 per cent intake, regardless of PGR or dietary energy concentration. The ad libitum fed pigs took fewer days to reach 60 kilograms, grew faster, ate more and had improved feed efficiency. However, the efficiency of energy utilized for protein or lipid deposition was improved with the lower intake.

“The efficiency of the utilization of dietary energy for growth was comparable among pigs selected for high or low potential growth rate,” concluded Beaulieu.

This implies that segregating pigs and feeding based on their potential growth rate is not a tool that will improve our ability to match feed to requirements.

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