Pakistan Journal of Nutrition 8 (7): 1068-1073, 2009 ISSN 1680-5194 © Asian Network for Scientific Information, 2009 1068 Influence of Nutritional Flushing Prior to Mating on the Performance of West African Dwarf Goats Mated in the Rainy Season P.K. Karikari and E.Y. Blasu Faculty of Agriculture, KNUST, Kumasi, Ghana Abstract: The effect of nutritional flushing for a period of six weeks prior to mating on the physical condition, serum metabolic and hormonal status at mating and litter size at birth of 32 pluriparous West African Dwarf (WAD) goats was studied using a 2 × 2 factorial design. The factors in the design were age (young, 3-4 years old versus old, 5-6 years old) and nutritional flushing regime (pasture alone versus pasture plus concentrate supplementation). The young does gained more weight and body condition (2.0±0.30 kg; 0.53±0.10 units; p>0.05) over the 6-wk nutritional flushing period than the old does (1.4±0.30 kg; 0.40±0.10 units), but the old does were heavier (p<0.05) at mating. The overall mean (±SE) total serum protein was 86.1±0.76 g/l at mating and did not differ (p>0.05) between treatments. The serum glucose concentrations were also similar for the treatment groups and averaged 2.6±0.10 mmol/l at mating. At the end of the nutritional flushing period, supplemented does had a higher (p<0.05) serum concentration of insulin (19.1±0.63 versus 15.1±0.63 <mu>IU/ml) than the unsupplemented does. Young does also had higher (p<0.05) serum insulin concentrations (19.8±0.63 <mu>IU/ml) than old does (14.3±0.63 <mu>IU/ml). Serum Luteinizing Hormone (LH) concentration at mating was similar for supplemented and unsupplemented does, but was higher (p<0.05) for young does (11.8±0.23 < mu>IU/ml) than for old does (1.8±0.23 <mu>IU/ml). Young does had a higher litter size (1.81±0.12) than old does (1.50±0.12) and supplemented does had a larger litter (1.81±0.12) than the unsupplemented does (1.50±0.12). These differences were, however, not statistically significant (p>0.05). There was, however, an interaction between age of doe and nutritional flushing treatment with young does that were supplemented having a mean (±SE) litter size of 2.13±0.18 compared to 1.50±0.18 for each of the other three treatment groups. It was concluded that young (3-4 years old) does may benefit from concentrate supplementation of wet season grazing, but that old does (5-6 years old) will not benefit from this supplementation if they are in moderate body condition six weeks before mating. Key words: Age, condition score, goat, native pasture, reproduction, supplementation INTRODUCTION The West African Dwarf goat is the predominant goat breed in Ghana. This breed can be bred all year-round and has been shown to be potentially prolific. A litter size of 1.8 (Devendra, 1990; Awotwi and Fynn, 1992) and fertility rate of 99.0% (Awotwi and Fynn, 1992) have been reported for the breed in Ghana and elsewhere. But others have reported litter sizes of 1.67 and 1.56 (Ikwuegbu et al., 1994) and as low as 1.30 (Reynolds 1989; Baffour-Awuah et al., 2005) for the breed. Nutrition and age differences partly account for the variation in the reproductive performance reported for the breed (Adeoye, 1985 and Chowdhury et al., 2002). Nutrition is generally recognized as a significant MATERIALS AND METHODS regulator of reproduction. Flushing has, therefore, been Location and duration of experiment: The experiment reported to positively affect the body condition, fertility was conducted at the National Goat Breeding Station at and ovulation rate of dams with poor nutritional status Kintampo, a town in the Brong Ahafo Region of Ghana, just before or during mating. Flushing can be located at 08 03’N and 01 43’W. The area falls within the accomplished either by allowing animals to graze lush transitional or derived savannah ecological zone, which nutritious pasture or by feeding energy-rich supplements lies between the forest zone and the interior savannah. (Luginbuhl and Poore 1998; Johnson, 2001). But meat The vegetation is a mixture of tall trees, shrubs and goat production can be more profitable only if maximum grasses. The mean annual rainfall is about 1300 mm. use is made of quality pasture and browse (Luginbuhl About 69 and 31% of the rains occur in the wet (April- and Poore, 1998). The small stature of the WAD goat suggests that flushing with lush native pasture, which is possible at the start of the rains, can be successful, but traditionally flushing is associated with concentrate feeding. African goats are reported by some researchers to reach their optimum reproductive performance between the ages of three and four years while others put it between five and six years (Adeoye, 1985; Webb and Mamabolo, 2004). This experiment was, therefore, to investigate whether WAD goats, segmented according to age, will gain reproductive advantage from concentrate supplementation of wet season grazing. o o