| dc.description.abstract | Dehorning of cattle is a common procedure
worldwide, and it has been reported that it is often
carried out without any antiseptic preparation of the
skin around - the horn prior to the operation. The
aseptic technique is not considered practical or even
necessary for many operative procedures performed on
cattle (Heinze, 1970). The aseptic technique is,
however, known to play an important role in the
healing of wounds in general and no~ observing i~
results in the invasion of tissues by pathogenic
bacteria which delay or prevent healing. The skin is
also known to be a common source of contamination of
wounds in animals. This project was ~herefore
designed to investigate the effects of antiseptic
preparation of the skin around the bovine horn on the
rates of infection and healing of dehorning wounds.
A comparison was also made between cosmetic
dehorning, where the horn wound is sutured, with the
standard method where the dehorning wound heals as an
open wound.
Sixty horns of thirty cattle of mixed breeds and
over one year of age were dehorned. Two groups of
five cattle each were dehorned with no antiseptic
preparation of the skin around the horn prior to the
operation. One group was then housed in stalls in a
building while the other was maintained on a farm
under field conditions. Two other groups of five
cattle each were dehorned following complete
antisepsis which included shaving the hair around the
horns using a scalpel blade, washing the area with
soap and water and applying surgical spirit. One
group
farm
was then housed in stalls and the other on a
under field conditions. A fifth group of five
cattle had partial antisepsis done prior to dehorning
which involved trimming short the hair around ~he
horns using scissors and washing the area with soap
and water. This group was kept on a farm where
healing took place. The las~ group of five ca~tle
had cosmetic dehorning performed, and complete
antiseptic preparation of the skin around the horns
was done prior to the dehorning. These animals were
housed in stalls after the dehorning and the healing
of the wounds was observed. In all the dehorning
operations the surgeon ensured his hands as well as
the equipment used were clean ~o minimise the
contamination from these sources.
The following parameters were studied: the time
taken for the antiseptic preparation and dehorning,
which was measured using a stop watch; the types of
microorganisms on the skin around the horn and the
difference in this microbial population after
antiseptic preparation; the incidence of infection of
the .horn wounds (Sinusitis) and the microorganisms
causing it. Samples for microbiological culture and
identification were taken using a sterilised swab
culturette, streaked on a blood agar plate and
incubated at 370 C for 24 hours. Rectal temperatures
and blood leucocyte levels were also assessed every
week to determine whether the infection of the horn
wounds was spreading to affect the rest of the
animal's body. The healing rate was determined by
measuring the wound size each week following
dehorning using Calipers. The healing time as well
as the appearance of. the horn wounds on healing were
also studied.
More time was spent in observing complete
antisepsis than partial antisepsis and no antisepsis
in that order. Complete antiseptic preparation more
effectively reduced the microbial flora on the skin
around the horn as compared to partial antisepsis.
The incidence of sinusitis was however similar for
all the animals dehorned in the standard way
irrespective of the method of antiseptic preparation
or the place where the animals were housed during
healing.
The microorganisms isolated most commonly in
sinusitis
vulgaris,
in order of prevalence
Pseudomonas aeruginosa
included Proteus
and Escherichia
coli, which are common faecal contaminants of the
environment of the animals. The rectal temperatures
occasionally rose above the physiological limit in
the animals with sinusitis, but soon re~urned to the
normal range. The blood leukocyte levels did not
vary significantly from the normal physiological
limits in all the animals, with or without
sinusitis. Sinusitis, when it occurred, did not
delay or prevent healing unless it was prolonged and
epithelial cell migration had reached ~he frontal
sinus opening.
The dehorning wounds where comple~e antisepsis
was observed had a shorter healing ~ime ~han the ones
where partial or no antisepsis was observed. The
wounds where partial antisepsis was observed in turn
healed faster than those where no an~isepsis was
observed. Cosmetic dehorning took a longer time to
perform than the standard method of dehorning but all
the animals healed withou~ developing sinusitis.
These animals also healed faster as compared to the
standard method (without suturing the skin wound).
In the standard method, incomplete wound contraction
was observed resulting in a large epi~helial scar and
an irregular skin margin which was unattractive in
appearance. In cosmetic dehorning, however, the skin
edges fused well with little scar formation with an
attractive postoperative appearance.
Antiseptic preparation, and more specifically
shaving or trimming the hair around the horns prior
to dehorning, were found to enhance the healing of
the horn wounds. The application of antiseptics did
not reduce the rate of infection of the horn wounds,
or sinusitis, and this was most probably due to
contamination from the environment. The sinusitis,
when it occurred, did not spreaa to affect the
general health of the animal. Cosmetic dehorning was
more expensive and time consuming than dehorning
without suturing the skin wound, but it had the
shorter healing time, least infection rate and a more
attractive postoperative appearance. | en |
