Feeding the Post-Weaned Pig

Striking the right balance of starter diet allowance can bring savings, according to new research from Agri-Food and Biosciences Institute (AFBI) in Northern Ireland.
calendar icon 29 September 2010
clock icon 6 minute read

Feed costs contribute over 70 per cent of the total cost to produce a pig and starter diet, which are offered to pigs after weaning, are the most expensive diets that pig producers will buy.

Recent research conducted at the Agri-Food and Biosciences Institute (AFBI), Hillsborough and co-funded by Pig ReGen Ltd and the Department of Agriculture and Rural Development has found that savings can be made by striking the right balance of starter diet allowance.

Finding the right balance of starter diet allowance can optimise pig performance and economic returns

In Northern Ireland, Greenmount benchmarking data indicate that on average post weaned pigs are offered 7kg per pig of starter 1 diet followed by 13kg per pig of starter 2 diet (also called ‘link’ by some producers). Post-weaned pigs in the AFBI Hillsborough herd are offered a markedly lower allowance of 3kg and 6kg per pig of starter 1 and 2 diets, respectively, and performance post-weaning is considered good, with pigs attaining weights of on average 30kg by 10 weeks of age with a feed conversion ratio of 1.33.

In light of this, a research programme was developed, in conjunction with Pig ReGen Ltd, to evaluate the potential to refine starter diet feeding regimes in the industry.

The starter 1 diet used in this research contained 16.5MJ per kg of digestible energy, 22.5 per cent crude protein and 1.7 per cent total lysine, while the starter 2 diet contained 16.25MJ per kg digestible energy, 21.5 per cent crude protein and 1.55 per cent total lysine. There is a range of starter diets available within the industry. Whilst ingredient composition cannot be ignored, producers need to compare the energy, protein and lysine contents of the diets they are using to put this research into context.

The Research

Results from Hillsborough

In trial 1, when pigs were offered either 2, 4, 6 or 8 kg per pig of starter 1 diet no improvement in daily gain, feed conversion ratio or pig weight post weaning (to 10 weeks of age) was observed.

In trial 2, all pigs were initially offered 4 kg per pig of starter 1 diet and then offered either 6, 8, 10 or 12 kg per pig of starter 2 diet. Increasing the amount of starter 2 diet did not improve pig performance post weaning either.

In trial 3, either 0 or 2 kg per pig of starter 1 diet was offered, followed by 4 kg per pig of starter 2 diet. In this trial, pigs were 2.2 kg lighter at 10 weeks of age when no starter 1 diet was offered compared with when 2 kg of starter 1 diet was offered.

In addition, feed conversion ratio was seven per cent poorer between weaning and 10 weeks of age when no starter 1 diet was offered. It cost an extra £1.16 per pig in feed costs to offer 2kg per pig of starter 1 diet but it was estimated that the extra weight gain at 10 weeks of age and improved feed conversion ratio post weaning would have resulted in an extra carcass value of £3.37. Therefore, in this case the extra carcass value outweighed the investment in feed costs.

On-farm trials

Farms differ in their health status, weaning weight of pigs and management ability. For these reasons, similar trials comparing levels of starter diet allowance were conducted on two commercial farms.

On both farms, the same starter diets were used as highlighted above, although medication was specific for each farm. Pigs were offered either a) 2kg of starter 1 diet followed by 6kg of starter 2 diet or b) 4kg of starter 1 diet followed by 8kg of starter 2 diet. Results are presented in Table 1.

No significant improvements in the weight of pigs or their average daily gain were observed on either farm when pigs were offered the higher allowances. However, feed conversion ratio was improved by three per cent on one farm and five per cent on the other farm.

Previous research studies using different starter diets also found improvements in feed conversion ratio post weaning when similar levels of allowances are compared.

Table 1. The effect of different starter diet allowances on post weaned pig performance on two commercial farms
Value Farm 1
2kg - 6kg
Farm 1
4kg - 8kg
Farm 2
2kg - 6kg
Farm 2
4kg - 8kg
Wean weight (kg) 7.4 7.2 8.6 8.6
End weight (kg) 18.4 18.9 23.5 23.8
Average daily gain (g per day) 350 361 438 439
Average daily feed gain (g per day) 455 449 595 561
Feed Conversion Ratio 1.30 1.23 1.32 1.28


It appears that the very high allowances of starter diets that are being used by some benchmarking units in Northen Ireland are unnecessary. On the other hand, the exclusion of starter 1 diet is not advisable.

Farms differ in health status, management and weaning weights and this study has demonstrated that some farms will benefit more from slightly higher allowances of starter diets than others. It appears that the use of 2 to 4kg per pig of the above starter 1 diet followed by the use of 4 to 8kg per pig of the above starter 2 diet optimised performance post weaning. However, it is advisable that whilst ‘ranges’ can be suggested, individual producers should monitor pig performance and feed usage in order to economically evaluate and conclude what the optimum allowances are for their production system.

A final trial within this programme of research, which is currently underway, is investigating the effects of starter diet allowance on the lifetime performance of pigs.

September 2010

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