The over-muscled sow syndrome: A modern problem

A paper addressing the newly classified syndrome of the over-muscled sow drew a lot of attention at the last edition of the IPVS Congress, held in Vancouver, BC, Canada. Its author, Dr Thierry Solignac from France, was awarded the fourth Janssen Pig Management Award for it, as the jury was unanimous in its decision. What makes the theme so special?

By Emmy Koeleman and Vincent ter Beek
Dr Solignac is both a veterinarian and nutritionist, working at Coopagri in Brittany, France. He wrote the article together with Alassane Keita and Eric Pagot, from CTPA Zoopole in France and G.P. Martineau, from the Ecole Vétérinaire, Toulouse, France.
His winning paper was titled The over-muscled sow syndrome: a new emerging syndrome in hyper-prolific sow herds: Preliminary field observations on farrowing duration. Solignac and his co-workers developed a feeding programme that reduces the muscularity in sows at farrowing. “Over-muscular sows are becoming a real problem, the high lean meat percentage is due to genetics and it comes with additional problems, for both the animal and farmer,” said Solignac.
Overmuscularity, Solignac reported, has a negative impact on farrowing, lactation and behaviour. He wrote that the syndrome “emerges as a consequence of the selection for deposition of lean meat and hyperprolificacy.” This way, the syndrome joins other factors that can affect duration of farrowing such as breed, litter size, parity, body condition and housing. Typically, fat sows are classically reported having long farrowing but the correlation was never found to be very high.
Materials and methods
Solignac tried to prove that the amount of body muscle does have a significant effect of the duration of farrowing. For that goal, duration of farrowing was registered from 482 sows of 14 commercial herds in Brittany, France, with different hyperprolific genetics. For each sow, they measured body fat (BF) and body muscle (BL) on site P2 at farrowing.
Each sow was then classified according to the body fat and the body muscle median values: BL+ when the value was above the median value and BL- when it was below. The same procedure was applied for body fat. Major results are reported in Figure 1. There is a statistically significant effect of body muscle on the duration of farrowing (p=0.04). Sows with above average body muscle showed a farrowing duration of 3.9 hours versus 3.6 hours for sows with below average body muscles. The effect of body fat and genetics proved not to be significant. In his conclusion, Solignac wrote that, “Over-muscled sows are candidates for long farrowing.
Management of lean deposition is of crucial importance. There is a need to modify our paradigmatic view of sow nutrition according only to their needs. Indeed, we have to take into account the fact that selection for high capacity of lean deposition has negative consequences on many parameters.”Solignac also found that sows with a morphotype with above average body fat and body muscle on average have litters under 13 piglets, wheareas sows with litters having more than 15 piglets had below average body fat and body muscle. “The negative consequences on prolificacy in fat sows are probably an indirect consequence via the decrease of feed intake in lactation. Therefore, management of lean deposition and fat deposition is of major importance during mid-gestation,” Solignac wrote. “Moreover, the management of lean and fat deposition is of crucial importance, as soon as the sows are in the gilt development unit.”
There are ways to deal with overmuscularity, Solignac explained: “We cannot change the genetics, that is a fact, but we can adjust the sow's back lean percentage (and thus muscularity) by adjusting the diet. We have developed a feeding scheme, which is primarily focused on lowering the lysine content during certain periods of pre-mating and gestation,” he said.
Lysine is the main nutrient that has an impact on lean tissue. The gilts are given a low lysine diet before mating, except for the last 15 days before mating till 21 days after mating, then the animals receive a high lysine diets. The last 21 days before farrowing, the sows again receive a high lysine diet and with the time in the middle the lysine content is again reduced. “By reducing the lysine content by 20% in the diet, during certain periods, we can reduce the back lean content by 10% approximately,” said Solignac.This 10% reduction – and thus less muscular sows during farrowing and lactation – has many advantages. The farrowing goes smoother, the lactation is better and the sows are less aggressive. Solignac said he was honoured with the fourth Janssen Pig Management Award. He commented, “I am very happy with this award, as this topic is very important and will become a bigger problem in the near future. I hope this award will increase the awareness of this topic among other veterinarians and nutritionists.” PP
The fourth Janssen Pig Management Award is an initiative of Janssen Animal Health. This year, for the first time Pig Progress and Vetsweb were the event's media-sponsors.
References are available on request.
Source: Pig Progress magazine, Volume 26.7


Pig Progress, volume 26, no.7 2010

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