Lameness in fattening pigs – Mycoplasma hyosynoviae, osteochondropathy and reduced dietary phosphorus level as three influencing factors: A case report

Abstract

BackgroundMultiple diagnostic procedures, their results and interpretation in a case with severe lameness in fattening pigs are described. It is shown that selected diagnostic steps lead to identification of various risk factors for disease development in the affected herd. One focus of this case report is the prioritization of diagnostic steps to verify the impact of the different conditions, which finally led to the clinical disorder. Assessing a sufficient dietary phosphorus (P) supply and its impact on disease development proved most difficult. The diagnostic approach based on estimated calculation of phosphorus intake is presented in detail.Case presentationOn a farrow-to-finishing farm, lameness occurred in pigs with 30-70 kg body weight. Necropsy of three diseased pigs revealed claw lesions and alterations at the knee and elbow joints. Histologic findings were characteristic of osteochondrosis. All pigs were positively tested for Mycoplasma hyosynoviae in affected joints. P values in blood did not indicate a P deficiency, while bone ashing in one of three animals resulted in a level indicating an insufficient mineral supply. Analysis of diet composition revealed a low phosphorus content in two diets, which might have led to a marginal P supply in individuals with high average daily gains with respect to development of bone mass and connective tissue prior to presentation of affected animals. Finally, the impact of dietary factors for disease development could not be evidenced in all submitted animals in this case.ConclusionsMycoplasma (M.) hyosynoviae was identified to be an important etiologic factor for disease. Other, non-infectious factors, such as osteochondrosis and claw lesions might have favored development of lameness. In addition, a relevant marginal P supply for pigs was found in a limited time period in a phase of intense growing, but the potential interaction with infection by M. hyosynoviae is unknown. The presented case of severe lameness in fattening pigs revealed that three different influences presumably act in pathogenesis. Focusing only on one factor and ignoring others might be misleading regarding subsequent decision-making for prevention and therapy. Finally, clinical symptoms disappeared after some changes in diet composition and anti-inflammatory treatment of individual animals.

Dietary supplementation of 25‐hydroxycholecalciferol as an alternative to cholecalciferol in swine diets: A review

“…Clinical metabolic bone disease, which can develop due to compromised bone mineralisation caused by dietary imbalances or dysregulations of mineral homeostasis, is a possible cause of lameness and fractures (Madson et al, 2012; Wegner et al, 2020). Due to their rapid growth rate, especially in the late rearing to early finishing phase, and limited sunlight in conventional housing systems, pigs are particularly susceptible to developing rickets (Dittmer & Thompson, 2011; Madson et al, 2012).…”

“…Osteochondrosis is a degenerative, multifactorial disorder of the immature skeleton that results in lesions of the growth plate cartilage (Olstad et al, 2015, 2018, 2019) and lameness (Wegner et al, 2020). Sugiyama et al (2013) found in growing pigs (6−10 kg) that dietary supplementation of 50 µg/kg 25‐OHD 3 was able to reduce the incidence of osteochondrotic lesions analysed by macroscopic examination of articular cartilage of the distal humerus (32.4% vs. 59.3%) and distal femur (47.1% vs. 87.5%).…”