| dc.description.abstract | An investigation was conducted to assess the incidence
and. identify the predisposing factors of bovine
squamous cell carcinoma in Kenya. The incidence, breed
susceptibility, sites of origin and age distribution of
squamous cell carcinoma found in the four breeds of grade
cattle in Kenya are reported along with the observed correlation
between lack of pigmentation of the bovine vulvae
and occurrence of bovine vulva carcinoma. Typical examples
of the histology of bovine squamous cell carcinoma which
were observed during histological diagnosis are also shown.
The data of 18 cattle with vulva carcinoma and 48
cattle with ocular carcinoma on which immunotherapy trials
were conducted are reported. The details of the preparation
of the saline phenol extract of bovine squamous cell
carcinoma used in the study are outlined. The methods by
which immunotherapy trials were conducted are described.
rIt was found that bovine vulva carcinoma and bovine ocular
carcinoma on the eyelid skins did not respond to the extracts
while bovine ocular carcinoma on the cornea,sclera
and third eyelid responded favourably to the extract. It
was noted that the larger the lesion the poorer were the prospects
of regression. It is concluded that immunotherapy
is a promising modality of therapy for bovine ocular car(
cinomaon the cornea, sclera and third eyelid but must as
yet be considered as experimental and additional trials are
needed to determine its therapeutic efficacy, mechanism of
action and the active antigenic substance in the extract.
The data of 62 cattle with vulva carcinoma on which
cryosurgery trials were conducted are reported. The methods
by which cryosurgery trials were conducted and the equipment
used are described. It was found that bovine vulva
carcinoma responded favourably to cryosurgery trials.
It was noted that the larger the lesions the poorer were
the prospects 6f achieving a complete cure and that the
use of thermocouple needles was imperative for safe and
effective treatment. It is concluded that cryosurgery is
a safe and practicable technique with few complications
and that it should be regarded as one of the treatments of
,choice for bovine vulva carcinoma especially of early
clinical lesions.
The results of the immunotherapy phase of this
study categorize bovine squamous cell carcinoma into two
groups viz: Ci) bovine vulva carcinoma and bovine ocular
carcinoma on the eyelid skins Cii) bovine ocular carcinoma
on the cornea, sclera and third eyelid. The type of this
malignancy in group I is thought to be caused by exposure
of unpigmented or partly pigmented skins of the vulvae and
eyelid to high levels of solar irradiation while the type
of this malignancy in group II is thought to be caused by
a virus.
A hypothesis is advanced that breeding programmes
designed to raise Ayrshire cows with high levels of melanin
pigmentation on their vulvae and Hereford cattle with red
around their eyes are feasible long term measures to
eradicate the group I type of this malignancy. The results
of the immunotherapy phase of this study indicate that the
application of active-specific immunotherapy is the hope Of
the future in treating the group II type of this malignancy. | en |
