Remote Sensing Model Of Sheep DMI And Estimation Of Heterosis,Maternal Effect And Direct Breed Effect

Twelve lambs born spring of 2005 and weaned on May 5 and three 1.2 ha bermudagrass paddocks were used to evaluate the relationships between animal forage intake and forage canopy spectral absorbance over a nine week period, and also estimate heterosis, maternal breed effects and direct breed effects for forage intake,in order to optimize livestock production system of grazing sheep,keep balance of grassland-livestock and environment improvement. Forage canopy spectral reflectance measurements (350nm to 2500 nm) were made weekly using ASD Fieldspec in eight random spots in each of the three pastures. Forage was harvested weekly (eight samples per pasture) and fed for two 24-hs periods each week. Specific samples were fed to specific lambs on each harvest to pair intake with hyperspectral readings. The lambs were divided into three groups of four animals, with each group consisting of one lambs from four breed groups: Katahdin×Katahdin (KK), Katahdin×Suffolk (KS), Suffolk×Katahdin (SK), Suffolk×Suffolk (SS). Experiment was carried on in advance, in order to adjust the best design of experiment. Intake data were analyzed by mixed model least squares and residuals adjusted for fixed effects were output for stepwise regression on hyperspectral absorbance readings. Results were analyzed by LSD. Averaged over the two days per week and nine weeks of the study, DM intake as a percent of body weight averaged 2.58%, 2.60%, 2.90%, and 2.66% in Katahdin , Suffolk, Suffolk x Katahdin, and Katahdin x Suffolk, respectively. Intake was the highest in the Suffolk x Katahdin ewe lambs (P < 0.10) compared to the other three breed groups and significant,KS and SK consumed more 0.24kg DMI per increasing 1kg BW(0.24 kg/kg BW,P < 0.01). Maternal breed effect of DMI for KK was lower than SS and significant(-0.24 kg/kg BW,P < 0.10). These results indicated that maternal breed effects can play an important role in regulating intake in grazing animals and that breed composition should be considered in the design of efficient grazing systems.Dry matter intake od hyperspectral remote sensing estimation model were made with stepwise regression. The R2 from the"best"10-variable regression model was 0.27 and wavebands included ranged from 420 to 988 nm. The R2 values from the"best"20, 30, 40, and 50-variable models were 0.49, 0.61, 0.73 and 0.81, respectively. The"best"60-variable model had an R2 of 0.92 with wavebands ranging from 418nm to 997nm. Plots of measured...