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Aspects of artificial breeding in goats

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Ball, Peter Douglas (1996) Aspects of artificial breeding in goats. Unspecified thesis, University of Tasmania.

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Abstract

This study examines some aspects of the application of artificial breeding technology to
the breeding of Cashmere goats. The development of young male Cashmere and
Angora goats was also studied.
Experiments were undertaken to develop a simple procedure for freezing caprine semen
in polyvinyl straws suspended in liquid nitrogen vapour. Such a methodology was
determined and assessed in the laboratory against a more conventional method of
freezing semen in pellets on solid carbon dioxide (dry ice). Acceptable rates of sperm
survival after freeze-thawing were achieved for the straw freezing procedure.
However, sperm survival was greater after freezing semen as pellets.
Artificial insemination programs were conducted with the aim of improving fertility
from both laparoscopic and cervical insemination procedures in Cashmere goats. The
factors examined included the hormonal control of ovulation, the time of insemination
relative to ovulation, the number of motile sperm inseminated, the depth of cervical
insemination, and the age and parity of the females. Fertility was improved by
insemination prior to the estimated time of ovulation, and with increasing depth of
cervical insemination. Fertility was reduced in kid maidens compared with both hogget
maidens and multiparous adult does.
Fertility resulting from the laparoscopic insemination of semen processed and frozen as
pellets and straws was also assessed. The fertility achieved with straw frozen semen
was not significantly less than from semen frozen in pellets.
A method was investigated for production of inseminate containing high densities of
motile spermatozoa for use in cervical insemination. This semen was frozen at dilution
rates of 1:0.5, and 1:1 (Semen:diluent). Whilst the percentage of spermatozoa
surviving this process was lower than for conventional dilution rates (1:2), the
concentration of motile spermatozoa was up to 1.8 times greater in semen frozen at 1:0.5. There was no benefit to fertility from this technique, although fertility was not
significantly reduced. Fertility was not significantly affected by timing of
insemination, double insemination or the number of motile sperm inseminated.
In addition, a small study was also conducted to examine the affects of breed
(Cashmere and Angora), early weaning and foster rearing on the early growth and
development of young goat bucks. There was no significant affect of rearing strategy
on live weight or testis weight. Testis weight was more closely related to live weight
than age in the young buck, and was highly predictable from measures of scrotal
circumference. The growth and development of the smaller group of Angoras studied
was significantly slower than that of the Cashmeres. Late spermatids and released
spermatozoa were observed in 48% of the semifflferous tubules of Cashmeres at mean
age 19 weeks and mean live weight 16.8 Kg.

Item Type: Thesis (Unspecified)
Keywords: Goats, Goats
Copyright Holders: The Author
Copyright Information:

Copyright 1996 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Thesis (M.Ag.Sc.)--University of Tasmania, 1996. Includes bibliographical references

Date Deposited: 25 Nov 2014 00:47
Last Modified: 08 Jun 2016 03:06
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