Effect of Litter Bed on Growth Performance and Odor Emission in Fattening Lamb

In view of the problem of odor non-point source pollution in fattening area of mutton sheep in recent years, the effects of bedding bed on growth performance of fattening lambs and odor components in the house were discussed, so as to provide technical path for odor emission reduction in fattening sheep house.

Two-hundred fifty healthy fattening lambs with similar weight and age were used and randomly divided into 5 groups according to different bedding materials, which were control group (plain soil), group A (full-sawdust), group B (furfural + sawdust), group C (rice husk + sawdust), and group D (corn cob + sawdust). The trial period was 90 days (d 1-45 in early period; d 46-90 in late period). The odor components in environment above and inside the litter bed were detected by using GC-MS method during different periods, and the effect of litter bed on production performance in fattening lambs was also analyzed.

(1) Compared with the control group, the four groups with litter bed demonstrated an increase in daily feed intake (P<0.05), which was increased by 7.7% in group A and 8.7% in Group B, 12.1% in Group C, and 7.8% in Group D. However, the daily gain and ratio of feed to gain exhibited no difference (P>0.05). (2) Nine kinds and eight kinds of odor components were detected throughout test period above litter bed and inside litter bed, respectively, and the components consisted of 31 kinds of volatile organic compounds (VOCs), including 4 alcohols, 10 alkanes, 3 amines, 1 phenol, 7 esters, 4 ketones, 2 aldehydes, 3 acids, and 1 thiol. The odor kinds detected in 4 litter groups were basically same as the control group. (3) From content analysis of odor components, the alkane content was the highest with 52.0%-77.5% among all odor components, no matter experimental period or detected space; however, no difference was observed among all groups (P>0.05). Also, the content of phenol or amine in litter groups demonstrated a decrease (P<0.05) in two detected spaces in early and late periods, compared with the control, exhibiting the decrease in group C was obvious. Besides, the content of alcohol, amine, or phenol was higher (P<0.05) in early period than that in late period both upper and inner spaces of litter bed; however, the ester content in late period was higher (P<0.05) than that in early period. (4) During entire experimental period, four kinds of key odor-causing substances were detected both in upper and inner of litter bed, including 2-ethylhexanol, N,N-dimethylacetamide, phenol, and 1 H-indole-3-thiol. For the contents of the four odor-causing components, each litter group showed a decreasing trend, compared with the control group, and the decrease in group C was the most obvious (P<0.05).

In summary, four combined litter beds in this study could improve growth performance in fattening lambs, and decrease odor content in environment. The results would provide a technical pathway for reduction of odor emission in sheep barn.