Lameness: A stealthy thief that robs performance

peet on pigs A 2007 survey estimated lameness accounts 
for 15 per cent of the gilts and sows that are culled

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Lameness in sows is a stealthy thief because losses from this health problem often go unnoticed or unrecognized, says Mark Wilson of Zinpro Corporation in Eden Prairie, Minn.

“Lameness is one of the major reasons for culling in gilts and sows,” Wilson said at the recent London Swine Conference.

“There are several causes of lameness including arthritis, osteochondrosis, disease and claw lesions.”

A 2007 survey estimated lameness accounts for 15 per cent of the gilts and sows that are culled.

“This number is likely underestimated because animals that are culled for reproductive reasons and for age are also often lame,” said Wilson. “Besides concerns for welfare of the animals, culling due to lameness impacts herd dynamics and reduces productivity.”

Often losses or removal due to lameness occur in gilts and first parity sows.

“Generally, the value of herd replacement gilts is not paid for until they have had at least three litters,” said Wilson. “Each additional litter that a sow has above the third litter dramatically reduces the fixed cost of piglet production.”

Improving longevity through the prevention of claw lesions will have a large economic impact, he said. Increasing the number of sows in parity three to six has a large impact on overall productivity of the herd. The most important aspect is to attend to the management issues — primarily feeding and nutrition — that help prevent claw lesions and lameness, thus improving longevity, he said. As replacement rates are reduced, herds become immunologically more stable and productivity improves, he added.

Lameness not only increases the likelihood of early removal from the herd but research also shows it causes a highly significant reduction in sow productivity.

“One of the obvious consequences of lameness is pain and inflammation causing a reduction of feed intake,” said Wilson.

“If a younger parity sow does not eat well they generally have reduced reproductive performance. There is a direct relationship between daily feed intake during lactation and the time taken for sows to express estrus after weaning.”

Longer weaning to estrus intervals are associated with poorer farrowing rate and lower litter size in the subsequent parity. Wilson stressed the importance of achieving a high lactation feed intake in young females and suggested prevention and early treatment of lameness and claw injuries will help maintain appetite and feed consumption.

Many of the claw lesions and injuries found in sows are inflammatory-type wounds. Wilson said mechanisms that result in these lameness and foot injuries impacting reproduction are similar to those involved when there is a lack of nutrients.

“Is it any wonder that we see more sows abort or absorb embryos, decreased litter sizes born, and a lack of return to estrus when sows are severely lame?” he asked.

The presence of non-cycling ovaries was the most common (nine per cent of sows) problem found in the reproductive tracts of cull sows during a 2007 survey. The incidence of this problem increased as sow body condition decreased and was also correlated with rear foot abscesses. However, Wilson noted, not all sows with claw lesions will exhibit changes in appetite and feed consumption. The injury must be inflammatory to see these responses.

Many aspects of nutrition impact claw health, including energy, protein, macro minerals, trace minerals and vitamins. Feeding organic minerals in an amino acid complex has been shown to improve feet lesion scores, milk production and reproductive performance in dairy cattle. Although further research is needed in sows, some trials suggest that nutrition may play an important role in supporting the immune system and improving lameness and reproductive performance.

“When the minerals zinc, manganese and copper were provided in the diet as an amino acid complex in a controlled experiment, results showed a decrease in claw lesions of sows housed in gestation crates, compared to those fed the same mineral levels as sulphates,” Wilson said.

“The results indicated that the sows fed trace minerals as amino acid complexes had significantly less lesions on the hind limbs than control sows.”

Also, analysis on the prevalence of lameness indicated it was lower for the sows fed trace mineral amino acid complexes (34 per cent versus 51 per cent) compared to sows fed inorganic trace minerals. When reproductive performance was evaluated, the treated sows had more pigs born alive (11.07 versus 10.44) and litter birth weight also tended to be higher (16.99 versus 16.16 kilograms).

Claw health is crucial to the overall well-being of the sow, Wilson concluded.

“Claw lesions that penetrate the corium — the deep inner layer of the skin, under the horn of the hoof — increase the potential for inflammatory response and are associated with pain, lameness and decreased productivity,” he said.

“Because lameness and reproductive failure are two of the most prominent reasons for early removal from the sow herd, feeding and management to help prevent claw lesions and lameness should begin early in the development and selection of gilts.”

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