GENETIC PARAMETERS OF growth AND REPRODUCTION IN THE WEST AFRICAN DWARF GOATS
GENETIC PARAMETERS OF GROWTH AND REPRODUCTION IN THE WEST AFRICAN DWARF GOATS
Twenty Does (dams) and five Bucks (sires) of mature West African Dwarf goats that were under strict management were employed in the experiment. The goats were divided into five groups of four for mating.
One buck (sire) and two does (dams) are given at random to each pen. Each animal was given access to fresh water, pasture, and 1 kilogramme of Cajanus cajan concentrates every day. Data on birth and weaning weights, litter size, and linear body measures were gathered.
The sire component of variance, from which the additive genetic variance and heritability were computed, was estimated using the paternal half-sib analysis model. According to the descriptive data for birth weight, litter size, body weight increase, and coefficient of variation (mean S.E.), the offspring's birth weight varied considerably (P 0.05) between sires.
Different sire groups' offspring's weaning weights showed no statistically significant differences (P>0.05). Significant variations in sires group body weight growth were observed (P 0.05). Male offspring were higher than female offspring in terms of body weight, body weight gain, arm length, and height at wither.
The effect of season of birth revealed that children born in the dry season had higher daily weight gain (44.163.11g) than those born in the wet season (42.323.74g). The estimates of heritability for birth weight, litter size, and weaning weight were low (0.15), moderate (0.22), and high (0.88), respectively.
Body length heritability estimates at birth were considered to be moderate, but at 6 months of age, the heritability was high (0.95), indicating a strong potential for genetic improvement.
Body length, arm length, and height at wither showed high heritability values as linear body measuring features. In West African Dwarf goat traits, phenotypic, genotypic, and environmental correlations between two parameters ranged from -0.01 to 0.99.
Nigeria had 144 million residents according to the national census of 2006 (National Population Commission, 2006). The current gap in the supply of animal protein is certain to expand given the rate of population expansion, the increasing extinction of native livestock species, and rising production costs.
The Nigerian government has been attempting to improve the native breed of livestock by importing exotic breeds since the 1970s in an effort to close the gap between the demand and supply for animal protein.
The main reason these efforts failed was because the exotic breeds could not adjust to the tropical environment of Nigeria because the obstacles posed by tropical diseases and pests were intolerable to them.
Native breeds that have evolved to their local habitat are better able to endure and produce high-quality goods in unstable and low-input situations (AGRI, 2002).
According to Maijala (1983), indigenous goat breeds are currently receiving genetic improvements because they have a long history of adapting to extremely difficult environmental conditions related to nutrition, climate, and disease. They might be more effective than exotic varieties in their natural habitat.
They may also be beneficial as experimental subjects in basic science research and as a potential repository of rare genes, which may be particularly helpful if adjustments to the production system are required due to environmental concerns (Salako and Ngere, 2002).
Because of their inherent adaptive traits, such as toughness in the challenging tropical environment and trypano-tolerance, the indigenous small ruminant populations in Nigeria, which include sheep and goats, are significant genetic sources (Salako, 2004).
The West African Dwarf goat is the most common breed of goat in the humid tropics among the many goat breeds in the world. The ability of farmers and buyers to relate the live animal measurements to growth characteristics is essential for optimal production and value-based trading system because the majority of these are bred under the traditional management and their contribution to the total supply of meat in the region is enormous.
Additionally, this capability will fairly compensate livestock farmers rather than the middlemen who typically make more money from the livestock production industry, particularly in poor nations (Afolayan et al., 2006).
Because most farmers in the tropics lack weighing scales and the training to comprehend their manipulations, a study of linear body measurements is crucial (Gerald, 1994).
According to Gerald (1994), linear body measurements can be used to estimate animal weight and market value.
1.1 OBJECTIVES OF THE STUDY
This study's main goal was to identify the genetic factors that influence the growth and reproductive characteristics of West African Dwarf (WAD) goats raised in the humid tropics.
The specific goals include assessing the growth performance of West African Dwarf (WAD) goats, figuring out the influence of sex and season on performance traits,
figuring out the heritability of litter size, growth, and body measurements in WAD goats, and figuring out the genetic, phenotypic, and environmental relationships between body weight and body measurements at different ages.
1.2STATEMENT OF THE PROBLEM
Nigeria's needs for animal protein are met via animal agriculture (Ogbu, 2010). This entails a great deal of responsibility. A minimum of 34 grammes of animal protein per kilogramme of body weight per day is advised by the British Medical Association (Okunenye, 2002).
The average daily intake of animal protein in Nigeria was 7.6g, according to Ogbu (2010).When examining the various economic sectors in 2000, the Central Bank of Nigeria found that the Gross Domestic Product (GDP) had been trending downward.
Given that the nature of GDP reflects citizens' standards of life, Nigerians' quality of living has been falling. This suggests that the typical Nigerian must consume significantly less animal protein than is advised.
Nigeria must import animal milk and meat products from other nations to make up for this reduction. Ironically, Nigeria has been a net importer of animal goods since the 1980s while having a vast amount of domestic livestock resources (Okunenye, 2002).
Indigenous cattle species have been completely ignored, which has led to their continued underdevelopment. Therefore, it is essential that efforts be focused on enhancing the native to the tropics West African Dwarf goat.
The West African Dwarf Goat's carcass yield, acceptance as a meat animal, and income will all increase if its growth characteristics and reproductive abilities are improved.
1.3 JUSTIFICATION OF THE STUDY
The quality and quantity of the meat and milk produced by West African Dwarf (WAD) goats, which offer animal protein essential to a healthy human diet, might be greatly improved.
Goats are mostly kept in Nigeria for the purpose of producing meat. Goats are more prolific than cattle among the ruminants. Short generation intervals and high prolificacy provide a quicker way to close the gap in the country's present intake of animal protein.
The genetic parameters and characteristics of the animal for economic qualities should be regularly assessed in order to maximise gains from environmental impacts.
This is because choosing which animal to buy, sell, cull, or mate depends on factors such as the size of the animal in relation to its age and the evolution of growth performance. The most precise and reliable way to determine body weight for cattle is to use scales that have been properly calibrated.
Knowing the weight and age of a goat may be challenging in farm environments without scales or records. Animals can be measured linearly to determine their body size as well as their weight.
Goats' changing dentition from birth to maturity can be utilised to determine their age. According to Awgichew and Abegaz (2009), the management system, pregnancy, gut fill, and breastfeeding all affect a goat's weight.
This study aims to look at the genetic factors influencing the growth and reproductive characteristics of a population of West African Dwarf (WAD) goats raised in the humid tropics.