Estimating the energy expenditure of farm animals at pasture is important for efficient animal management. In recent years, an alternative technique for estimating energy expenditure by measuring body acceleration has been widely performed in wildlife and human studies, but the availability of the technique in farm animals has not yet been examined. In the present study, we tested the potential use of an acceleration index, overall dynamic body acceleration (ODBA), as a new proxy for estimating the energy expenditure of grazing farm animals (cattle, goats and sheep) at pasture with the simultaneous evaluation of a conventional proxy, heart rate. Body accelerations in three axes and heart rate for cows (n = 8, two breeds), goats (n = 6) and sheep (n = 5) were recorded, and the effect of ODBA calculated from the body accelerations on heart rate was analyzed. In addition, the effects of the two other activity indices, the number of steps and vectorial dynamic body acceleration (VeDBA), on heart rate were also investigated. The results of the comparison among three activity indices indicated that ODBA was the best predictor for heart rate. Although the relationship between ODBA and heart rate was different between the groups of species and breeds and between individuals (P<0.01), the difference could be explained by different body weights; a common equation could be established by correcting the body weights (M: kg): heart rate (beats/min) = 147.263∙M
-0.141 + 889.640∙M
-0.179∙ODBA (g). Combining this equation with the previously reported energy expenditure per heartbeat, we estimated the energy expenditure of the tested animals, and the results indicated that ODBA is a good proxy for estimating the energy expenditure of grazing farm animals across species and breeds. The utility and simplicity of the procedure with acceleration loggers could make the accelerometry technique a worthwhile option in field research and commercial farm use.
In the present experiment, semi-purified diets containing 10% of either cellulose, pectin, alginic acid or finely ground rice straw as a dietary fiber were given ad libitum to 1-week-old White Leghorn male chicks for 3 weeks, and the effects of such fibers on chick growth and feed efficiency, development of internal organs, utillzation of protein and energy, and lipid content in the body were investigated. The intake of the pectin diet was very low compared with that of the other diets, and this resulted in lower body weight gain and lower feed efficiency. Relative growth rate of internal organs (length or weight on body weight basis) was also influenced by pectin feeding. The length of esophagus, the weight of crop, both the length and weight of duodenum, small intestine, ceca and rectum were increased by pectin feeding. Alginic acid also increased the length and weight of small intestine, ceca and rectum, but the extent was less than that of pectin. The weights of gizzard and liver were increased by rice straw feeding. The weights of esophagus, proventriculus, heart, pancreas and spleen were not different between the treatments. Retention rates of dry matter, energy and nitrogen of the pectin group were inferior to those of the other groups, and this might be due not only to low feed intake but to low utilization of the nutrients. Levels of phospholipids and total cholesterol in carcass , liver and blood plasma, and of triglycerides in liver and blood plasma were not different between the treatments, but triglyceride level in carcass was lowered by pectin feeding.
This study investigated the feed intake, and energy and nitrogen partition of growing lambs fed on diet with fish silage (FS) as a major protein supplement. The FS was compared with the conventional protein feeds like fish meal (FM) and urea (UR). Six castrated and 6 female Suffolk lambs were divided into three groups and fed on Italian ryegrass silage (IRS) as basal ration at 70% on dry matter (DM) basis. The protein based concentrate mixture of FS, FM or UR was supplemented to one of the three groups at 30% DM. The DM intake of animals was not affected by FS diet and was comparable with the other diets. Likewise, the organic matter intake and digestible organic matter intake (DOMI) of the animals were unaffected by the varying protein supplements. The nitrogen retention of FS group was 37% higher than that of the UR group, however, the FM group was significantly higher than the UR group (P<0.05). The retained energy of FS group with 116.6kJ/ kg W 0.75/d tended to decline compared to the other groups. The methane energy and methane production of the FS group which were 79.1kJ/kgW0.75 /d and 55.6 L/kg DOMI, respectively, had a lower tendency while the heat production with 13.2MJ/kg DOMI tended to increase compared to the other treatments. The respiratory quotient of the FS group with 1.09 tended to be lower than the other groups. These results suggest the potential of fish silage as a major protein supplement but further investigation is needed to upgrade the palatability and nutritional value.
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