According to Claire LeFevre, DVM, Carthage Veterinary Service, one of the key steps in identifying causes of lameness is to ensure that caretakers correctly recognise it.

Many employees have never worked with livestock before, so it’s important for farm managers, department heads and veterinarians to educate them about the signs of lameness. Caregivers need to understand that early identification helps prevent end-stage conditions such as severe abscessation at the coronary band, which frequently results in euthanasia.

Focus on subtle signs

Educating caretakers can be challenging due to the normal variation in sow locomotion and differences in individual housing, but there are several consistent signs of lameness that can be taught. The focus needs to be on early, subtle lameness signs since lameness is obvious if an animal is not weight-bearing and holding up an affected limb.

For sows in stalled gestation barns, caretakers are advised that the best time to find early clinical signs of lameness is after feed is dropped in the morning. Lame sows are slow to stand, which makes it easy to identify those needing treatment. In addition, a sow’s reluctance to get up and eat can lead to a loss in body condition.

It’s easier for caretakers to spot problems in penned gestation barns. Signs to look for include toe-tapping or weight-shifting while standing. These sows need to be moved to stalls for more focused attention during recovery.

In any type of housing, other signs of lameness may include vocalisation when attempting to rise or abnormal posturing.

Review farm records

Once lameness has been identified as an issue in a herd, several steps can be taken to obtain more information regarding the cause.

We review farm records to further characterise the reasons sows need to be removed and treated for lameness. For example, removal trends might be discovered among certain parities, phases of production or locations within a facility.

An increase in removal of younger parities might indicate osteochondrosis or degenerative joint disease. An unusual number of sows being treated for lameness in one location during gestation should prompt an investigation of the facilities that might reveal problems with penning, slats and feeding stations.

In pen gestation or electronic sow-feeding systems, it can be revealing to review stocking density and parity grouping to ensure the farm’s practices align with standard operating procedures. Gilt training and sow behaviour during queuing are other areas that need to be evaluated.

In group pens, fighting during mixing time points to an increase in the likelihood of claw lesions, which are among the most prevalent causes of lameness observed.

Consider caretaker surveys

Experienced caretakers may be able to provide more information in the form of a survey about the animals treated or euthanized for lameness. The information gathered can include the limbs and joints involved or the location of suspected lesions based on the presence of swelling or other observations. It’s really helpful if caretakers can take photos of the more prevalent lesions, assuming camera use is approved by management.

Survey responses and photos should be reviewed by a veterinarian who knows the herd history. The veterinarian can further investigate the case by performing necropsies if indicated and collecting diagnostic samples, which can lead to more specific diagnoses.

While most lameness in sows is not infectious, injectable antibiotic therapy can be initiated if lameness is identified early and there are signs of bacterial infection, such as swelling or exudate present at the lesion site. However, injectable therapy for lameness is often unrewarding, and infectious lameness is more common in growing-pig populations. Lame sows that require antibiotic treatment should be identified and treatment needs to be recorded so the antibiotic can be withdrawn at the required time.

Of course, prevention is the better approach since there are limited options available for treating lameness in sow herds. Proper maintenance of sow housing and facilities helps reduce the incidence of sow lameness. It’s always a good idea to work with your nutritionist to ensure the diet is optimal for each phase of production.

Another important area of focus is gilt development. Caretakers need to make sure there’s an adequate supply of gilts and toward that end, should be trained to select gilts with correct structural soundness. If there aren’t enough gilts to allow for culling of lame sows, then there’s pressure to use lame sows to meet breed targets.

Lameness investigations in sow herds can be frustrating, no doubt. However, getting to the root cause helps prevent economic losses that occur when lameness leads to retention of lame sows, production issues — or worse — when lameness leads to sow mortality that might have been prevented.