Estudio integral de la cornamenta del toro de lidia. Efecto del enfundado y detección de posible manipulación mediante termografía

Abstract

Historically, the bull horn has been an iconic symbol for the bovine species. Horns within each cattle breed have unique characteristics. The lidia breed is no exception as the horns of lidia bulls are known to contribute to their aggressive character and image. The bulls that fight in the plaza de toros, or bullfighting ring, must arrive as a sound specimen with their horns personifying the fullest symbol of integrity. The bull’s horns are valued so much that owners place a special protection around their horns their last year of life on the ranch. Their horns remain covered, with a cast, to avoid damage when animals are managed in cattle facilities, as well as reducing lameness or death due to goring. There is a paucity of scientific literature associated with the anatomy of the bull horn. As a result, the current work aims at broadening the scientific literature related to its morphometry, histology, and external hardness. At the same time, we analyzed potential effects exerted by the cast protection placed around the horns. Finally, we aimed to validate a technique to measure temperature as a method to detect fraudulent manipulations of bull horns prior to bullfighting when the veterinarian provides a review of the animal in the pen. For the morphological analysis, we measured 372 horns from lidia bulls, within Frace and Spain, belonging to 10 different encastes within bulls between three to six years old. We took nine measurements manually with a measuring tape and caliper, including: external and internal lengths, vertical and horizontal diameters in the cepa, pala and piton, and the distance between the pitones. The results demonstrate that horn dimensions are homogenous, detecting significant differences in horn diameters and distance between the pitones within the encaste Miura, whose animals exhibited the thickest horns. However, we did not detect differences related to either internal or external lengths, which supports more uniformity within the horn morphometry. The results coincided with the existing, yet limited, data published about horn measurements within the lidia bull literature. Related to the histologic study, we aimed to determine if protecting bull horns with the special resin may have an influence on the histological structure within the lidia bull breed. To do so, we sampled horns from 30 animals between four and five years old killed in bullfighting rings comparing with a control group of 15 animals whose horns were never protected. Our results suggest that the histological structure of the bull horn is normal and that minor defects or cellular changes observed could not been attributed to wrapping the horns. Thirdly, we quantified the external hardness of the lidia bull horn with the aim to determine if wrapping influenced the hardness. To do so, we collected 390 horns from animals that fought in either Spain or France. Bulls were three to five years old. We compared them to a control group with 118 animals whose horns were never wrapped. In particular, we analyzed the horn hardness at three locations—cepa, pala y piton—using a hardness instrument PCE-D shore®. At the same time, biometric information was collected from the horn. We noted the presence of lesions on the horn and the animal’s coat. We observed that the animals whose horns were wrapped were not as hard at either the cepa or the piton. In horns that exhibited damage, such as scrapes or chips, the piton hardness was less. Finally, the jabonero bull horns were softer at the piton compared to horns of other animals. Lastly, to test the application and use of a thermographic technique to detect any fraudulent manipulation of bull horns before bullfighting, between 2014 and 2019, we studied 208 animals from diverse cattle ranches that fought in Zaragoza. Of those, 11 bulls fought as “rejoneo” and their horns were legally modified and were used as a positive control. After thermographic images of bull horns were taken, horn dimensions of animals suspected of horn manipulation were significantly different compared to those animals not suspected of having their horns altered. We did not record any bull fulfilling the legal requirement of 1/7 the total average length that was not classified as suspect after evaluating the thermal images, which could be considered a false negative. Within the suspected animals, 89.47% did not fulfill the required horn measurements. These results strengthen the idea that thermographic instruments can be used by veterinarians as a tool to obtain objective data when faced with a scenario whereby horns may have been manipulated.