ABSTRACT
Effect
of frequency of ejaculation on semen characteristics of heavy ecotype chicken
raised in the derived savannah region of Nigeria was studied using twelve heavy
ecotype cocks. The cocks were randomly assigned to three treatments with four
cocks in each treatment. Ejaculation frequencies once, twice and thrice per
week, with T1 representing once, T2, twice and T3, thrice were
imposed on the birds. The experiment lasted for a period of eight weeks with a
two-week pre-experimental period during which cocks were trained for semen
collection and six weeks of semen collection schedule. Feed and water were
supplied ad libitum during the experiment. Semen collected were analysed for
volume, progressive sperm motility, percentage live and dead spermatozoa, percentage
normal and abnormal sperm cells, sperm concentration and total sperm in the
ejaculate. Result showed that ejaculate volume and total sperm in the ejaculate
were not significantly (p>0.05) affected by the ejaculation frequencies
while progressive sperm motility, percentage live and dead sperm cells,
percentage normal and abnormal sperm cells and sperm concentration were all
significantly (p<0.01) affected by the ejaculation frequencies. Cocks
ejaculated twice weekly recorded the highest value sperm in motility 77.70 ±
0.99% , live 76.04 ± 0.90% and normal spermatozoa, 77.29 ± 0.85% while cocks
ejaculated thrice weekly recorded the lowest values of 65.96 ± 1.87%, 66.38 ±
1.90%, 68.40 ± 1.92% for motility, live and normal spermatozoa respectively.
Also the cocks ejaculated thrice recorded the highest value for dead (33.44 ±
1.90%) and abnormal spermatozoa (31.59 ± 1.92%) while cocks ejaculated twice
recorded the lowest values of 23.95 ± 0.90%, 22.70 ± 0.85% for dead and
abnormal spermatozoa, respectively. It was concluded that twice weekly
ejaculation gave better semen quality. Therefore, it is recommended that twice
per week ejaculating frequency should be used for cocks for optimum semen
quality and for high semen output.
CHAPTER ONE
INTRODUCTION
1.0 Background of the study
Rapid
human population growth and low protein intake are some of the major problems
facing developing countries like Nigeria. Poultry production is one of the
surest and fastest means of bridging the animal protein supply needs of any
nation, especially for countries like Nigeria where it has been reported that
an average individual consumes about 7.5g of animal protein as against 28g
consumed by an average Briton (Mmereole et al., 2001).
The
local chickens constitute the majority of poultry types in Nigeria, being about
106 million in population (Ajayi, 2010) with more than 80% in the rural areas
where they contribute substantially to annual meat and egg production. There
are various ecotypes of local chicken in the different agro ecological zones of
the country and they vary in shape, size and plumage colours (Oluyemi et al.,
1982). The different ecotypes can be grouped into two major categories on the
basis of body size and body weight as ‘light’ ecotype and ‘heavy’ ecotype
(Momoh and Nwosu, 2008). Light ecotype refers to those types belonging to the
swamp, rainforest and derived savannah agro-ecological zones whose mature body
weights range between 0.68-1.5kg. The heavy ecotype represents the types from
the dry savannah (Guinea and Sahel savannah), montane regions and cattle kraals
of the north, whose mature body weights range from 0.9-2.5kg (Atteh, 1990).
The
importance of semen evaluation in poultry breeding (natural and artificial
breeding), for selecting breeding males or for routine monitoring of their
reproductive performance cannot be over emphasized. Semen of breeding cocks is
usually evaluated to ascertain the quality before it is employed for breeding
programmes.
The assessment of semen quality characteristics of Nigeria local chicken
gives excellent indices of its reproductive potential (Zahradden et al.,
2005) and has been reported to be a
1.1 Objective
The
broad objective of this study was to evaluate the effect of frequency of
ejaculation on semen characteristics of heavy ecotype raised in Nsukka, Enugu
state.
Specific objectives were to evaluate the effect of
ejaculation frequencies on:
i.
Semen
Colour
ii.
Semen
Volume
iii.
Semen
Motility
iv.
Live and
dead spermatozoa
v.
Normal and
abnormal spermatozoa and
vi.
Sperm
concentration
1.3 Justification
High
semen output is achieved through frequent ejaculation and the volume and
concentration determine the number of females to be inseminated. Semen needs to
be evaluated so as to ascertain its quality for use in artificial insemination
(AI). Artificial insemination is one of the most effective and widely used
techniques for the genetic improvement of farm animals. It is employed on
breeder farms to maintain the maximum use of males, as well as to ensure
disease prevention, high fertility rates and for economic reason. To obtain the
maximum number of spermatozoa and maintain high rates of sperm production, the
semen needs to be collected at a frequency that maintains output over time.
Therefore, the result of this study will help in determining the frequency that
gives better semen quality for use in the genetic improvement programme of
local chicken ecotypes in Nigeria.....
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Item Type: Postgraduate Material | Attribute: 50 pages | Chapters: 1-5
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