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Heavy pigs at weaning improve growth efficiency

One of the key principles of the Weaning Capacity approach to genetic selection is that the focus on quality and consistency of the weaned pig provides the potential for fast, lean efficient growth after weaning.

Both research and commercial experience demonstrate a clear relationship between weaning weight and growth rate to market. Also, faster growing pigs are more efficient converters of feed and deposit lean tissue faster, resulting in better carcass quality and a higher value per pig sold.

Clearly, weaning weight is a function of weaning age and growth rate during the suckling period. Generally, weaning age has been increasing in many European countries such that it is around 24-25 days on average. Even in North America, where a large part of the industry changed to weaning at 16-18 days during the 80s and 90s, there is now a realisation that later weaning has major benefits in terms of growth and production costs.  
 
The nursery phase
The period immediately after weaning is one of the most critical because it determines growth rate right up to market weight. Weaning weight is a major determinant of growth because bigger pigs eat more feed, have fewer health problems and therefore grow faster.

In this large-scale trial, pigs were weaned at ages from 12 to 21 days.  As weaning age and weight increased, feed intake and feed efficiency improved, resulting in a higher weight at 42 days post weaning.  Mortality also fell sharply as weaning age increased.

Heavier pigs at weaning have a better developed digestive system and are able to digest solid feed more efficiently, which not only leads to faster growth but also results in a lower incidence of health problems such as scouring.

The finishing stage
Weaning age continues to have a large influence on the performance of pigs at the finisher stage, because they enter the finishing barn at a higher weight and consequently continue to grow faster and more efficiently.

Because the majority of feed used is consumed at this stage, differences in efficiency have a large effect on production costs and margins. In a system with fixed availability of finishing space, more rapid growth results in a higher carcass weight and more revenue, as shown in the table. Although production cost per pig increases due to the heavier slaughter weight and consequently more feed consumed, the income over variable costs continues to increase with weaning age. 

Growth effects on carcass quality
There has recently been considerable interest in the effects on growth and carcass quality of reduced birth weight resulting from the rapid increase in numbers born achieved in some countries.  While this is a complicated topic, it seem quite clear that pigs with a lower birth weight, and by extension a lower weaning weight, not only grow more slowly and have more health problems, but have poorer carcass quality at the same carcass weight.

In this study, the percentage of body fat was higher and the size of the cells in the fat tissue was larger in the low birth weight pigs.  Additionally, the lean meat content of the carcass was considerably lower, while tenderness of the meat was significantly reduced.
 
Growth rate during the nursery phase has been shown to influence carcass quality, especially loin eye depth, but also backfat depth.  Weaning weight is the biggest influence on nursery growth rate, however, any factor that results in a reduction in growth rate, such as disease, poor environment or inadequate diets will also adversely affect carcass quality.

This is because in the early stages of growth pigs are depositing lean and very little fat and the more rapidly they lay it down the higher the lean content in the carcass.  Conversely, slow early growth means that more fat is deposited at the later stages of growth and the loin is less well developed at market weight.

Conclusions
Weaning Capacity is defined as the ability of the sow to produce the maximum number of heavy piglets during her lifetime.  It can be seen from the information shown above that smaller pigs at weaning have an extremely detrimental effect on growth, feed efficiency and carcass quality, all of which lead to reduced margins.

Hypor's approach is to maximise Weaning Capacity in order to ensure rapid, efficient growth from weaning to market.  This is done by selecting for a range of piglet quality parameters such as birth weight, numbers born alive and numbers weaned. Also, rigid selection for number and quality of teats, which determine milking ability, contributes to rapid piglet growth and high weaning weights. By taking a balanced approach to selection, we avoid the potential disadvantages of high litter size without improvements in piglet quality.

Hypor sows are capable of consistently producing large litters of heavy piglets, which maximizes the potential of the progeny in the nursery and finishing phases resulting in faster growth, more efficient feed conversion, heavier market hogs, improved carcass quality and higher margins.
 
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• Hypor

Editor PigProgress

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