Studies on grazing behavior of goats in the Cook Islands: The animal-plant complex in forage preference/palatability phenomena

A study on the grazing behavior of goats in the Cook Islands was undertaken during the dry season period to elucidate goat plant complex in forage preference/palatability phenomena. Three locations namely, the Seven-day Adventist School goat farm Paringaru goat farm and Prisons farm were selected for the study. The breeds of goats found in the locations are Sannen and crossbred Anglo-Nubian goats. A total of 110 goats with live-weight of between 18-35 kg were included in the study. There were some variations in the types of plant species available for gazing in the locations. Most dominant grass species were Guinea grass (Panicum maximum), Signal grass (Brachiaria decumbens), water grass (Commelina benghalensis), carpet grass (Axonopus compressus) (broad leaf), A. affinis (narrow leaf) and wild sorghum. Two creeping legumes Centrosema pubescens and Calopogonium mucuniodes including browse species such as Cassia spp., Bothriochloa spp., Leucaena leucocephala, Mor inda citrifolia, Mimosa pudica and borrelia spp were found in the different locations. Foliage of grass species was the dominant component of available forage in the three locations. Goats consumed Commelina benghalensis a weed commonly called "water grass" in the Cook Islands in the dry season period. Commelina benghalensis, has high moisture and high protein contents. Goats were observed also to eat the bark of Lantana camara a poisonous weed and Morinda citrifolia. Foliage cover, feeding time and preference index/palatability and selective grazing had effects on the quantity and quality of ingested fractions of available foliage by goats. Except for crude protein, there were no significant differences (P greater than 0.05) in nutrient contents of similar forages among the three locations. Axonopus affinis, Cynodon nlemfuensis and Panicum maximum had low crude protein values (5.7-8.5%). Available macro mineral content of grasses and legume/ browse species were co mparatively higher than the average requirements for growing goats. The high digestibility of nutrients including the fibre fractions and organic matter were due to preference/ palatability that influenced the goats to be selective and browse. In conclusion, this study demonstrate that goats like other small ruminants select their diets within the evolutionary processes of plant herbivore interactions, and available forage in the Cook Island is able to provide nutrients for the goats to meet growth requirements and other physiological functions.