Hypor - Weaning Capacity: the best measure of all factors

In the swine breeding industry, when customers or producers talk about the merits of sow lines, they mainly talk about the number of born piglets. The philosophy of Hypor R&D has moved beyond this to focus on Weaning Capacity.

Weaning Capacity is Hypor's description of a sow's ability, or capacity, to wean piglets. The term 'capacity' is used in the following manner: "This sow has high capacity to wean pigs". 'Weaning Capacity' is a 'composite" term that takes into account the different traits and measures that together contribute to the quantity and quality of weaned pigs. Aggregated into the meaning is the number of piglets born alive, pre-weaning mortality/survival, and hence the number of pigs weaned.

Another very important trait included as well is the milking ability of the sow. This constitutes the number of teats, her capacity and ability to nurture high numbers of piglets and her ability to produce heavier piglets in shorter periods of time. Often when sows farrow big litters and then have to suckle them, there might be a tendency to regress in the next cycle. This is particularly manifested in longer weaning to breeding intervals and reduced size of subsequent litters. Hypor maintains that the sow should be able to get the quantity and quality, yet re-breed in optimal time.

The geneticist's job is to combine the described traits in such a way that overall weaning capacity of the sow is made superior. However, genetic improvement is more complicated than just aggregating the best traits. The difficulty arises because some traits are positively correlated (improve together), and others are negatively correlated.

Examples of traits that are positively correlated are birth weight and post-natal survival - heavier pigs tend to have better liveability. Negatively correlated traits can be represented by litter size and birth weight - as litter size increases the tendency is for average birth weight to drop. Depending on breeding objectives, a breeder will either focus on a group of traits (for example in this case weaning capacity) or a single trait (number of piglets born - total or alive). Focusing on multiple traits tends to slow down the progress in individual traits due to the correlations between traits.

Most breeders know that it is quicker to achieve the result by focusing on one trait. A trait such as number of born piglets, can be achieved relatively quickly, but invariably at a cost. That cost will typically be the deterioration of other also important economic traits such as mortality/survival, quality of the piglets, weaning weights, growth rate, and other crucial traits.

The key is balance

Hypor's philosophy is to breed for the right balance between groups of traits to maximize the capacity to wean in a commercial sow. For instance, we do select for more pigs born, but we also include traits such as birth weight into the index. This ensures that as we make gains in the number of pigs born, we do not end up with increasing numbers of inviable piglets.

Experience in some breeding organisations has shown that when selection pressure is overwhelmingly tilted towards total born the frequency of inviable piglets, or runts increases. Another important aspect connected to this is the uniformity of the litter. It directly relates to the percentage of born-alive pigs that are weaned.

Another aspect mentioned earlier is milk production. Since this is all that piglets feed on in the first couple of weeks, milk production overwhelmingly influences weaning weight. While volume of milk produced is important we also believe that milk composition is a salient aspect. It is documented that Meishan pigs give birth to many relatively small piglets, but with substantially high survival rates. Meishans produce milk with a relatively higher fat content than most other breeds and thus it could be explained that their piglets though low in birth weight get "richer" milk and thus probably more take in more energy and have greater survival capacity. Placement, number and shape of the teats in the sow also make a difference. It is critical that the smaller pigs be able to get to the teats quickly for adequate milk consumption. If teat number is limiting or placement is not ideal, the weaker piglets will be out-competed and their survival becomes questionable.

Recent research is demonstrating that runts start as smaller piglets, wean smaller and also lag at finishing. These laggards can mean swinging one way or the other of the break-even line in the finishing barn. Thus the need to create the right balance in the sow barn.

By pursuing a balance in the sow with the view of maximizing both the quantity and quality of pigs weaned, the improvements are gradual for all traits and we avoid compromising one trait for the sake of another. In some cases, the choices are easy. If a breeder selects for more pigs born, than an accompanying negative result could be more piglets born dead. The point is that by combining many traits, even though some are negatively correlated, we can still progress to a better sow.

At Hypor weaning capacity is about balance and long term benefit. Exploiting one trait to the max shows well on a spreadsheet, but reduced survival and lower piglet quality show badly on the bottom line. At Hypor, weaning capacity is about balancing traits for the best possible combination.

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Hypor - Weaning Capacity: the best measure of all factors