Wild Cattle - Is it in their eyes?
Temperamental cattle are both dangerous and frustrating to handle. Animals who constantly try to leap over gates or charge towards openings are a danger to themselves, other animals and to their handlers. Injuries caused by this type of behavior affect the price of a carcass due to increased trimming of bruised areas. Temperamental cattle also have decreased gains in the feedlot as well as poorer meat quality. All of these factors contribute to lower profits for the producer.
Accuracy of measurements is a key aspect for genetic progress. Currently, there are many temperament measurements and evaluations that can be performed. These range from temperament scoring to flight speeds to physiologic responses. Each has its own pros and cons, including varying levels of accuracy.
Figure 1: Bovine Showing a Large Amount of Eye White
Temperament scoring can be completed while animals are restrained in a chute or during routine handling. A score between 1 and 5 is assigned to each animal, with 1 being calm or docile and 5 being agitated or aggressive. This method is easy and inexpensive to do, but relies on the consistency of the observer. Strict definitions of each score should be determined before evaluations occur and the same person should complete all observations in order to maintain precision. If these conditions are met, temperament scoring can be an effective method of evaluation.
Figure 2: Bovine Showing a Small Amount of Eye White
Flight speeds can also be calculated easily and may be a good predictor of temperament. The most common method is to record the time it takes an animal to exit a squeeze chute. This method can work well as long as there are not any changes in the surroundings, such as extra animals around the exit pen or sudden noises which may cause some animals to react uncharacteristically.
The third method, based on physiologic responses, often includes measuring changes in blood levels of cortisol, which is similar to adrenaline. Resting animals with higher levels of blood cortisol often have prolonged stress responses and more anxiety. However, measurement of this hormone can result in highly inaccurate evaluations of temperament because it is difficult to collect blood samples without causing stress to the animal. As well, this procedure is expensive. Additionally, cortisol levels can be increased for many other reasons, such as digestive processes, estrus cycles and circadian (daily) rhythms.
Current Selection Programs for Docility
Limousin breeders have made the greatest strides in improving temperament within their breed. They were the first to develop a temperament scoring system that could be used to rank animals with Expected Progeny Differences (EPDs) for docility. When the value of an EPD is high, there is a greater chance that the bull will pass on its docile traits. In 2005 the average EPD for docility in Limousin bulls was +12. These EPD values have improved significantly in the last 20 years. In 1990 it was estimated that the average EPD for Limousin bulls was only +1!
Since heritability for this trait is relatively high, genetic progress has occurred rapidly due to a high level of selection pressure. Through these intensive selection programs, it is estimated that Limousin breeders have increased the percent of docile animals by 16% in ten years. These breeders have shown that it is possible to improve temperament efficiently and that docility should become an industry breeding focus.
Table 1. Relationship of Flight Speed With Eye White %
Current Research on Evaluating Temperament
Recently, innovative research at the University of Guelph has shown that the percentage of revealed eye white can be used as a predictor of temperament. Eye white evaluations were conducted at the Elora Beef Research Station on bulls, steers and heifers as a graduate research project. This method was promising as it is an easy, inexpensive technique that can be consistently evaluated by a physical measurement rather than behavioural scoring. A digital camera was set up near the squeeze chute so that it captured the animal's eye. Video recording then took place while the animals were run through the chute. Images were then stored and analyzed to assess the amount of eye white revealed by each animal.
Flight speed was measured and chute score evaluations were also conducted. The results of these analyses showed that percentage of eye white had a significant positive correlation with both temperament scoring and flight speed. The correlations can be observed in Tables 1 and 2 (0.4 and 0.78 respectively).
The difference in per cent eye white between docile and temperamental animals within the study can be observed in images 1 and 2. This type of measure can be repeated on the same animal with a precision of 80 per cent. An additional benefit of this method is that it provides digital image records that can be used or re-analyzed at a later date. Since this measurement is reliable and highly correlated with temperament, percent eye white is a good tool for identifying animals that should be implemented in intensive selection programs for temperament.
Table 2. Relationship of Temperament Score With Eye White %
The study of temperament and its effects on productivity is a booming area of research, but so far the results are not widely used in breeding and selection programs. With increasing consumer demands for higher quality products and better management of livestock, selection for docility in cattle and other behavioural traits will play a key role in increasing profit margins throughout the beef industry. As technology improves, and better methods of assessment are developed, temperament will become an important part of future selection decisions.
- Data collection Assistance provided by the staff at Elora Beef Research Station
- Funding provided by the Ontario Ministry of Agriculture, Food and Rural Affairs
- Guidance Provided by Stephen Miller, Center for Genetic Improvement of Livestock (CGIL)
- Equipment and counsel provided by Tina Widowski and Georgia Mason, Campbell Centre for the Study of Animal Welfare (CSAW).
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|Author:||Sarah Core - MSc Candidate/University of Guelph, Center for Genetic Improvement of Livestock, Campbell Center for the Study of Animal Welfare|
|Creation Date:||8 July 2008|
|Last Reviewed:||12 February 2016|