Dr. Joseph M. Stookey
Almost all animal industries carry out some routine management procedures that cause
pain. Procedures such as castration, tail docking, branding, dehorning and beak
trimming all subject our food animals to, what we believe to be, short-term pain for long-
term benefits. There is little argument that the procedures are important, however, the
controversy arises when we begin to discuss how and when they should be carried out.
In regards to dehorning, should we use caustic paste, electric dehorners, cutters, wire,
gouges or scoops? Should we perform this procedure on day old calves or wait until
Department of Herd Medicine and
Theriogenology, Western College of
Saskatchewan, Saskatoon, SK
I have always believed that we (the people working within the industry) have a
responsibility to society and to our animals to identify the procedures that cause the
least amount of pain and the least amount of set back to the animal. Once the ideal
procedure has been identified we should try to move the industry towards that ideal.
However, as a researcher I do not believe we should be investigating the relative impact
of various dehorning techniques, when we could easily render them all unnecessary.
We already know that the least painful procedure and the one that causes the least set
back in growth is to remove horns by genetically selecting for polledness. In cattle,
horns are inherited as an autosomal recessive gene, polledness being dominant. In one
breeding season, a producer can take a herd of horned cows and breed them to a polled
bull (homozygous for the polled condition ) and have an entire polled calf crop.
You might ask, "Why should we worry about horns, maybe we should leave them on and
not dehorn cattle?" When horns are left on feedlot cattle, the amount of bruised trim
from the carcasses has been reported to be twice that from an equivalent hornless
group. The industry's desire to produce a consistently high quality product is
compromised by allowing cattle to enter our feedlots with horns. If we dehorn cattle
upon arrival at the feedlot, studies have shown the set back in gain can be detected for
up to 106 days post dehorning. The bruising and dehorning studies suggest that horns
should be removed sometime before cattle reach the feedlot. This concept is reinforced,
in many locations, by assessing a horn tax against cattle that are sold with horns. Even
for breeding stock, keeping the horns on the cattle comes at a price. Horns are used by
cattle in competitive situations. It is difficult to imagine even an extensive range system
where dominant cattle with horns would not use them against lower ranking cattle.
Certainly, cattle can exert their dominance within the herd using threatening postures
and not all encounters are settled through physical contact, but any producer knows that
on occasion the head of one cow will meet the hide of another. If cattle have horns, it
makes every competitive encounter at the feed bunk, hay bale, shade tree, water trough,
etc. potentially more dangerous for animals within the herd.
You might think that cattle (especially cows) need horns to defend themselves and their
offspring from predation in certain regions of the country. A very interesting study
conducted on African hoofed species belonging to the scientific family Bovidae (meaning
"hollowed horned ruminants", in which cattle belong) has shown that predation by lions,
leopards, hyenas, wild dogs, jackals, etc. is no higher or lower in species where females
have horns compared to species where females do not have horns. In fact, the hunting
and attack strategy of predators is no different if the prey is horned or hornless. In
addition, most Bovidae avoid predation by flight or concealment and not by defense. Out
of the 120 species of animals within the family Bovidae (which includes everything from
bison and giraffe to oryx and wildebeest), roughly 80 species have horns in both males
and females. In the other 40 species, only males have horns. If horns evolved as
weapons that were necessary to defend self and offspring then it would be
advantageous for all the females across all Bovidae species to have horns. The fact that
we find males in all the Bovidae species have horns, but not all the females has led
scientists to speculate that horns (plus antlers in deer, elk, and moose) evolved not as a
form of defense against predation, but as displays and weapons for males to use against
other males in competition to gain access to females.
If horns are not important for protection against predation and are used by males in
male-male competition, then why do females, such as cows, have horns? This is a
tougher question and certainly horns can be used as weapons for defense, but some
scientists speculate that horns on females may serve another purpose. One of the main
differences between species where both males and females have horns compared to
species where only males have horns is found in the social structure of the herd. Some
species form herds where the dominant males are year long residents and such species
tend to have both horned males and females (like cattle and bison). Some species form
separate female herds where the males show up only at breeding time and in most of
these species only the males have horns (like some species of sheep). This pattern has
led some scientists to speculate that adult females may use horns to mimic the
appearance of the developing horns of young males. Dominant males are therefore
reluctant to drive away young males that are developing horns because they look like
females. Scientists are speculating that thousands of years ago our female cattle with
horns may have been trying, in a sense, to "buy their males calves more time in the
herd" before they were driven away by dominant resident males.
Whether horns on female Bovids are really forms of sexual mimicry is speculation, but I
tell you all of this so that 1) you can realize that the presence of horns does not seem to
have any positive or negative effects on the level of predation and 2) horns probably
evolved for males to use in competition and in females as a way to "trick" the old males
to leave the young males alone. Either way, horns in beef cattle are the residual effect
of thousands of years of evolution and serve little function in today's beef industry where
we have eliminated much of the competition between males. Today, cattle function
perfectly well without horns in all the environments we keep them.
Are there other reasons we may want to keep horns in beef cattle? Some producers tell
me that they prefer certain horned breeds because they are superior to their polled
counterparts. Is this true? In 1996, Dr. Goonewardene from Alberta and I collaborated
on a project to compare the performance records of horned and polled Charolais and
Hereford bulls kept at two ROP test stations, one in Alberta and one in Saskatchewan
from 1985 -1993. We had access to the performance records of 578 Charolais bulls
(329 horned and 249 polled) and 1,860 Hereford bulls (1182 horned and 678 polled),
sufficient numbers to use for comparison.
As shown in Table 1 we found very little difference between the horned
and polled bulls in the traits that were measured at the stations. The polled Charolais
bulls did carry significantly more backfat than their horned counterparts, but they were
not different in average daily gain, adjusted yearling weight or in scrotal circumference.
We did find that the polled Hereford bulls in SK had a significantly higher average daily
gain compared to the horned bulls and tended to be larger yearlings. Polled Hereford
bulls in Alberta also tended to have a greater average daily gain, but the difference was
not considered significant. Another encouraging finding was that the ratio of polled bulls
at each test station over the time period had gradually increased as the number of
horned bulls decreased. In other words, the ability to locate good polled bulls is
becoming less of a problem than it had been previously.
Our findings were similar to other reports from various places around the world. A thesis
published by Lange in 1989 found no difference between polled and horned German
Simmental cattle in growth, carcass yield, carcass composition, health and reproductive
performance. Work reported by Frisch and coworkers from Australia in 1980, comparing
various beef breeds, showed no difference between horned and polled crossbred lines
in live weight, fertility and mortality rates. The dairy industry is not as fortunate as the
beef industry in finding acceptable polled sires. Dairy producers will not use a polled
sire until it can match the production traits of the horned bulls and the AI centers will not
put selection pressure or emphasis on polled lines unless there is a demand for polled
bulls. It appears that horned dairy calves will be with us for quite sometime! Since they
must dehorn, information on how and when to dehorn is important. The best evidence
suggests that the dehorning procedure causes the least setback and stress if performed
on dairy calves within the first week of life and which procedure is used makes little
Whether the level of pain an animal experiences is age dependent is still not known, but
we do know that the younger the animal at the time of the procedure the quicker the
healing process. Therefore we assume the entire procedure is better on the animal if
done at an early age.
There is no doubt that superior beef bulls can be found within either the polled or horned
population. However, because of the work and handling associated with dehorning, plus
the pain, set-back and stress on the animal, I believe beef producers should intentionally
select polled bulls. Historically, polled beef bulls may have been inferior, but there is no
evidence that overall differences still exist today. There are no data available to support
the notion that horned bulls are thicker, hardier and heavier boned, yet some producer
continue to make this claim. When I have tested producers and students, using slides of
bulls with the heads blocked from view, it is obvious that they are not able to accurately
separate horned from polled bulls. I have not tried a similar test in a slaughter plant, but
I am confident that the task of identifying which hanging carcasses belong to a horned or
polled animal would be impossible.
I believe that from an animal welfare perspective alone, we should be moving towards
dehorning beef cattle via genetic selection. Some may claim that because the pain,
stress and set back of dehorning is relatively brief, especially if we dehorn young calves,
that the issue of dehorning is not a very big welfare concern. Also, because town folks
rarely show up to help us with our daily chores it is easy to assume that somehow what
we do on the farm and the choices we make are not anyone's concern. This is simply
not true. If you raise cattle you are part of the beef industry and the image the
industry creates in the minds of the public has been shaped to some extent by the
choices made on each operation. Dehorning our beef cattle via genetics is a welfare
friendly practice that everyone in the industry should embrace and support.
Table 1. Averages of measured traits for horned and polled bulls at ROP
||1.36 .02 y
||1.41 .01 x
a Adopted from Stookey and Goonewardene, 1996. Can J. Anim. Sci. 76:1-5.
b University of Saskatchewan ROP test station data (1985-1992).
c Innisfail, Alberta, Hereford ROP test station data (1985-1993).
x,y Means with different letters are significantly different P < 0.05.
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