Rapid Communication: A comparison of cardiac lesions and heart weights from market pigs that did and did not die during transport to one Ontario abattoir.

In-transit losses of market hogs represent a small proportion of all market-weight pigs shipped in a year. This suggests that individual pig factors may be a significant cause of in-transit losses along with more traditionally considered environmental and transport factors. An investigation was performed to determine whether cardiac pathology and heart weights were associated with pigs that did or did not die during transport to an abattoir. The hearts from 70 pigs that died in-transit to one Ontario abattoir and 388 pigs that arrived alive were collected and examined. Hearts from pigs that died during transport demonstrated greater frequencies of cardiac lesions (P < 0.05). These included hypertrophy of ventricle walls (Left: 97% vs. 64%; Right: 86% vs. 57%), dilation of ventricle chambers (Left: 79% vs. 0.5%; Right: 100% vs. 5%), and dilation of the pulmonary artery and aorta (59% vs. 1.5%). Total heart weight to body weight ratios were increased (3.6 vs. 3.3 g/kg) and left ventricle plus septum weight over right ventricle weight ratio was decreased in pigs that died during transport over non-in-transit loss pigs (2.5 vs. 2.8; P < 0.05). This may indicate reduced cardiac function in hogs that died during transport. Pigs with reduced cardiac function would have exercise intolerance and be more susceptible to death during transport due to the increased cardiac workload required during sorting, loading, and transport of the pigs to the abattoir. Further research to quantify cardiac function in pigs with cardiac lesions or abnormal heart weight ratios is warranted.

Cardiac weights and weight ratios as indicators of cardiac lesions in pigs: A study of pig hearts from an Ontario abattoir.

Clinically healthy pigs used in research are assumed to have normal cardiac structure and function. Subclinical cardiac abnormalities may adversely affect the responses being measured in these experiments. The gross and histologic lesions observed in hearts collected from a Canadian abattoir between 2012 and 2015 indicated an unexpectedly high prevalence of cardiac abnormalities: 75% (297/396) of the hearts examined had such lesions. The ratios of total heart weight to body weight and of right ventricle weight to body weight were significantly greater for the hearts with lesions than for the hearts with no lesions, which suggests that cardiac remodeling, particularly hypertrophy, had occurred. The large percentage of hearts with cardiac remodeling from asymptomatic market pigs demonstrates an increased probability that subclinical cardiac abnormalities may exist in research pigs, especially those accessed through commercial channels. Researchers should be aware of this likelihood if subclinical cardiac abnormalities could adversely affect their experimental findings.

Les porcs cliniquement en santé utilisés en recherche sont présumés avoir une structure et fonction cardiaques normales. Des anormalités cardiaques sous-cliniques peuvent affecter de manière adverse les réponses étant mesurées dans ces expériences. Les lésions macroscopiques et histologiques observées dans les coeurs amassés d'un abattoir canadien entre 2012 et 2015 ont indiqué une prévalence élevée inattendue d'anormalités cardiaques : 75 % (297/396) des coeurs examinés avaient de telles lésions. Les ratios poids total du coeur/poids corporel et poids du ventricule droit/poids du corps étaient significativement plus élevés pour les coeurs avec lésions comparativement aux coeurs sans lésions, ce qui suggère qu'un remodelage cardiaque, particulièrement une hypertrophie, est survenue. Le pourcentage élevé de coeurs avec remodelage cardiaque provenant de porcs asymptomatiques prêts pour le marché démontre une probabilité accrue que des anormalités cardiaques souscliniques peuvent exister chez des porcs utilisés en recherche, spécialement ceux obtenus via des voies commerciales. Les chercheurs devraient être au fait de cette possibilité si des anormalités cardiaques sous-cliniques pouvaient affecter négativement leurs trouvailles expérimentales.(Traduit par Docteur Serge Messier).

Stall dimensions and the prevalence of lameness, injury, and cleanliness on 317 tie-stall dairy farms in Ontario.

The study objectives were to provide a province-wide description of stall dimensions and the aspects of cattle welfare linked to stall design in the tie-stall industry. Data on stall design; stall dimensions; and the prevalence of lameness, injury, and hind limb and udder cleanliness in lactating dairy cattle were collected from a sample of 317 tie-stall farms across Ontario. The majority of the study farms (90%) had stalls with dimensions (length, width, tie-chain length, and tie rail height) that were less than the current recommendations. This may explain, in part, the prevalence of lameness measured as the prevalence of back arch (3.2%) and severe hind claw rotation (23%), hock lesions (44%), neck lesions (3.8%), broken tails (3%), dirty hind limbs (23%), and dirty udders (4.6%). Veterinarians and producers may use this information to compare farms with the industry averages and target areas in need of improvement.