Effect of Potato By-products Based Silage on Rumen Fermentation, Methane Production and Nitrogen Utilization in Holstein Steers

Utilization of fruit and vegetable waste as an alternative feed resource for sustainable and eco-friendly sheep farming

Globally, 10-20% of horticultural wastes are disposed in landfills leading to environmental pollution. Recycling these wastes as animal feedstuff will lessen food-feed competition and minimize environmental hazards. The present study was undertaken to determine the nutritional quality of fresh fruit and vegetable waste (F&VW) and their dietary inclusion on nutrient utilization, antioxidant status, greenhouse gases (GHG) emissions and potable water sparing efficacy in sheep. Three dietary combinations were formulated i.e. control (C):70% Cenchrus ciliaris hay +30% concentrate mixture (CM), diet with fruit waste (FWD):70% Cenchrus ciliaris hay +20% CM +10% FW and diet with vegetable waste (VWD):70% Cenchrus ciliaris hay +20% CM +10% VW for in vitro and in vivo evaluation of these wastes as potential livestock feed. Twenty-one adult ewes were allocated into 3 groups C, FWD and VWD and fed on the above three diets. Dry matter and crude protein digestibility were significantly enhanced by 5.5 and 7.2%; 7.3 and 7.6% in F&VW supplemented groups, respectively, without affecting feed intake. Plasma total antioxidant capacity (TAC) was improved by 32.2 and 26.3% in F&VW supplemented groups. Inclusion of F&VW biomass reduced annual methane (CH₄) and nitrous oxide (N₂O) emissions (kg CO₂eq/sheep) by 3.12 and 4.55%; 15.18 and 14.92% and thus contributed to lowering of global warming potential by 4.00 and 5.27%, respectively. Furthermore, there was a net reduction of potable water consumption by 21.78 and 13.92% in F&VW supplemented groups, respectively. Therefore, it can be concluded that F&VW can be a potential feedstuff for ruminants and its efficient reuse would minimize environmental impacts associated with disposal of such waste in the landfills.

Molecular diversity of methanogens in feedlot cattle from Ontario and Prince Edward Island, Canada

The molecular diversity of rumen methanogens in feedlot cattle and the composition of the methanogen populations in these animals from two geographic locations were investigated using 16S rRNA gene libraries prepared from pooled PCR products from 10 animals in Ontario (127 clones) and 10 animals from Prince Edward Island (114 clones). A total of 241 clones were examined, with Methanobrevibacter ruminantium accounting for more than one-third (85 clones) of the clones identified. From these 241 clones, 23 different 16S rRNA phylotypes were identified. Feedlot cattle from Ontario, which were fed a corn-based diet, revealed 11 phylotypes (38 clones) not found in feedlot cattle from Prince Edward Island, whereas the Prince Edward Island cattle, which were fed potato by-products as a finishing diet, had 7 phylotypes (42 clones) not found in cattle from Ontario. Five sequences, representing the remaining 161 clones (67% of the clones), were common in both herds. Of the 23 different sequences, 10 sequences (136 clones) were 89.8 to 100% similar to those from cultivated methanogens belonging to the orders Methanobacteriales, Methanomicrobiales, and Methanosarcinales, and the remaining 13 sequences (105 clones) were 74.1 to 75.8% similar to those from Thermoplasma volcanium and Thermoplasma acidophilum. Overall, nine possible new species were identified from the two clone libraries, including two new species belonging to the order Methanobacteriales and a new genus/species within the order Methanosarcinales. From the present survey, it is difficult to conclude whether the geographical isolation between these two herds or differences between the two finishing diets directly influenced community structure in the rumen. Further studies are warranted to properly assess the differences between these two finishing diets.