Effect on average daily gain and economical impact of lung consolidation caused by Mycoplasma hyopneumoniae in finishing pigs

Author(s)

Maria Eugênia Silveira Ferraz

• Document type: Master's Dissertation
• Press: Jaboticabal. 2020-09-23.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2020-03-13
• Advisor: Luís Guilherme de Oliveira

Abstract

The aim of this study was to measure the impact of productivity and the consequent economical losses related to pulmonary lesions caused by Mycoplasma hyopneumoniae. Five-hundred finishing pigs, with approximately 75 days of age, were selected and weighed at the beggining and at the end of the phase to assess the average daily gain (ADG). These animals were evaluated at the slaughter, and samples were collected for laboratorial analysis to confirm presence of Mycoplasma hyopneumoniae DNA and/or antibodies. The lungs of each pig were examined and based on severity of macroscopic lung lesions the animals were classified into four groups: Group 1 – pigs without macroscopic lesions; Group 2 – 0.1-5% of lesions; Group 3 – 5.1-15% of lesions; Group 4 - >15.1% of lesions. Fourhundred eighty-six lungs were examined and 68.5% (n=333) had macroscopic lung lesions. All pigs with lesions were positive to Mycoplasma hyopneumoniae in ELISA and qPCR. Linear mixed regression models (proc Glimmix) were performed on SAS to estimate the effect of macroscopic lung lesion scores on the average daily gain of finishing pigs. Multiple comparisons between lesion score groups were performed using p<0.05. For each increase of one percent in the lesion area there was a decrease of 1.8 grams in the daily weight gain. All the groups had a numerically lower average daily gain when compared to Group 1 (no lesions). Group 1 had a numerically higher average weight, but not significant (p=0.2390 and p=0.2442), when compared to groups 2 and 3. However, when comparing groups 4 and 1, the last presented a significantly higher weight (p=0.0076). Group 4 also had a significantly lower weight averages when compared with groups 2 and 3 (p=0.0370 and p=0.0673). The negative correlation found between the group with no lung lesions and the group with more than 15.1% of lesions, showed a statistically difference in ADG, which could mean an opportunity to gain up to $ 6.55 per pig at slaughter (AU)

• FAPESP's process: 18/09473-2 - Productive and financial impact of lung lesions caused by Mycoplasma hyopneumoniae in growth pigs
• Grantee: Maria Eugênia Silveira Ferraz
• Support Opportunities: Scholarships in Brazil - Master