Optimization of Grazing Hour for Indigenous Sheep in Khulna Region

Abstract: Sheep is a small ruminant that required a small quantity of feed and they can thrive by grazing even in the poor-quality pasture in fellow land, roadsides, and dyke of shrimp farms. Therefore, the experiment was conducted to optimize the grazing hour of indigenous coastal sheep in the Khulna district of Bangladesh. Twenty female sheep before its first lambing belonging to the age of 4 to 6 months were divided into five treatment groups and allowed at random into five different grazing hours. The design of the experiment was based on a randomized complete block design (RCBD). Initially, the sheep were weighed and grouped keeping the average weight of five treatment groups almost similar. The allocated grazing hours for five treatment groups were 4, 6, 8, 10, and 12 hours, respectively. All groups of sheep were allowed to graze from 6 am to 6 pm during the research period of 12 March to 2 August 2020. During this period, the sheep of particular treatments groups were housed when their allocated grazing period was completed. All relevant data like body weight, date of onset of estrus, date of insemination, deworming, vaccination, and medication were recorded in a registrar regularly. Empty body weight data were recorded fortnightly in the morning before allowing them to graze. The body weight increased with the increasing grazing period but the mean differences were not varied significantly. In most of the cases, the highest body weight was observed in sheep grazed 10 hours per day. The average growth rate of grazing sheep at third and ninth weights varied significantly (p<0.01) among 4, 6, 8, 10 and 12 hours grazing groups. The mean differences in other cases also did not differ significantly. At the third weight, the highest growth rate (g/d) was reported to be 87.50 in sheep allowed to graze 10 hours followed by 12 (68.83), 8 (60.17), 6 (57.67), and 4 (39.00) hours of grazing. It can be concluded that the body weight and growth rate of indigenous sheep increased with the increase of grazing hours. However, due to the good quality of pasture 10 hours of grazing fulfilled their requirements for maintenance and growth. Keywords: Body weight, coastal sheep, grazing hour, growth rate, performance

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