VOLUME  55 (2) 2000

REPRODUCTIVE PERFORMANCE OF WEST AFRICAN DWARF GOATS IN THE HUMID TROPICAL ENVIRONMENT OF IBADAN.

Akusu, M.O. and Ajala, O.O.

Department of Veterinary Surgery and Reproduction, University of Ibadan, Ibadan, Nigeria

     Introduction      Materials and Methods      Results     Discussion

Introduction

Agricultural development in Nigeria has placed more emphasis on crop production although the rearing of cattle, sheep and goats have always formed an integral part of the domestic economy and source of wealth for Nigerians. The consequence of this imbalance is that most Nigerians consume far less animal protein daily than the minimum recommended level.

In the livestock sector some attention has been focused on non-ruminant farm animals, particularly poultry. Efforts have also been made to exploit the potential of cattle, whereas the goat has remained neglected and untapped. Various reports (1, 2) have shown that apart from poultry, the goat is the most numerous of the domestic livestock species in Nigeria. With goats numbering over 24,500,000 (3), it is estimated that there are 245 goats to 1000 Nigerians.

There are three main breeds of goats in Nigeria, the Red Sokoto, the Sahel and the West African dwarf goat (4). The West African dwarf goat is most prevalent in southern Nigeria. Its characteristics have been described earlier (4) while its relative trypanotolerance has singled it out as the breed of choice in southern Nigeria.

The West African dwarf goat is early maturing, prolific and a non-seasonal breeder (4,5). An average of 80.6% multiple births was recorded in one survey (6) and a total of 5 kidding in 3 years in another (7).

This present study is to investigate the effect of certain non-genetic factors on the prolificacy of the West African dwarf goat. It is hoped that the information generated will form part of a package required for profitable goat husbandry.

Back To Top    Introduction      Materials and Methods      Results     Discussion

Materials and Methods

Thirty adult West African dwarf goat aged between 1 and 4 years and 10- to 30 kg in weight were used for the study on fertility and prolificacy over a 4 year period. Following parturition, 9 does were assigned to a study on the variation of the post-partum period on oestrus cycle length. Another 8 does were used to study the effect of breeding at oestrus succeeding oestrus cycle lengths of short or long duration. The effect of the service period on the fertility and prolificacy of does was studied in 26 does; 13 were bred while suckling their kids (preweaning) while 13 were bred postweaning.

All animals were housed in roofed pens with concrete flooring and low wooden partitions. They were fed a corn-based concentrate ration (0.5 kg per day). Clean water and fresh giant star grass and centrosema were provided ad libitum while routine medication consisted of deworming with 10% Rintal (Bayer, Leverkusen) suspension and an ectoparasitic bath with Gamatox (Wellcome Coy, England).

Data were analysed by Chi square and Student’s t-test for the establishment of significance (8).

Back To Top    Introduction      Materials and Methods      Results     Discussion

Results

The fertility and prolificacy of the does were assessed from 77 services. Each doe became pregnant following breeding at each oestrus. Placentas were usually dropped within 10-30 minutes post partum.

The mean kid number per doe from the 77 services was 1.91±0.08. The male/female ratio of kids was 81/66 (i.e. 55.1% males). Male kids were heavier than female kids at birth (p>0.05). The mean birth-weight of the kids was 1.16±0.03 kg. Litter type had significant influence on kid birth-weight. The season of birth had no significant influence on birth-weight (Table 1).

Table 1: Effect of season, sex and litter size on birth weight

•  Number on the same vertical column differently superscripted differ significantly (p<0.05)
  

The mean gestation length for 68 observed parturitions was 144.9 days and was not significantly affected by season of birth. Does with singles had a longer gestation than those with twins or triplets. The mean gestation length in dams giving birth to only female kids was 1.13 days longer than in does with only male kids (Table 2).

Table 2: Effect of season, sex, litter size and parity on gestation

•  Number on the same vertical column differently superscripted differ significantly (p<0.05)
  

A total of 30 oestrus cycles were observed in 9 does post partum. The first observable post-partum oestrus occurred at 55.70±4.62 days.

The period was significantly longer (p<0.05) than subsequent cycles which were not significantly different from each other. The frequency distribution of oestrus cycle length is presented in Fig. 1 and Table 3. Table 4 summarises the influence of breeding during oestrus succeeding cycles of short and medium durations on some reproductive indices. The mean cycle lengths for short and medium oestrus cycles were 5.25±0.48 and 12.25±0.95 days (p<0.05) respectively. Oestrus duration and gestation lengths were not affected. Similarly, the mean kid birth-weights were not significantly influenced. However, prolificacy of does bred during cycles of medium duration was significantly superior (p<0.05) than their counterparts.

Fig 1.: Frequency distribution of oestrus cycle length in West African dwarf goats.

Table 3: Prevalence of oestrus cycle type (days) in West African dwarf goats

•  Number on the same vertical column differently superscripted differ significantly (p<0.05)

Table 4: Effect of breeding during short (A) and medium (B) oestrus cycle type (days) on some reproductive parameters of WAD goats (Mean ± SEM)