ABSTRACT
Four formulations of concentrate feeds, three contrasting qualities of grass silages, and mixtures of the silages (55%) and concentrates (45%, dry weight) were tested for in vitro fermentation kinetics, in vitro dry matter degradation (IVDMD), utilizable crude protein (uCP), and metabolizable energy (ME) values. The concentrates were pelleted control concentrate for dairy cows (CONT-P); pelleted alkaline concentrate with ammoniated cereal grains (ALKA-P); mash form concentrate with ALKA-P main ingredients but with feed-grade urea and barley replacing ammoniated cereal grain (UREA-M); and mash form of ALKA-P ingredients prior to alkalization (ALKA-M). The grass silages were early cut, late cut, and a mixture (1:1) of early and late cut. The objectives were to test if the feeds differed in the tested parameters within each feed category and assess the modulatory effect of concentrate feeds on the grass silage fermentation characteristics in the mixed diets. No interaction effects of the concentrate feeds by silage quality were observed for the tested parameters in the mixed diets. For concentrates, the pelleted diets were higher (p < 0.05) in IVDMD and molar proportion of propionate but lower in butyrate. The ALKA-P produced the highest estimated uCP (p < 0.01). For silages, uCP, ME, total short-chain fatty acids (VFAs), and molar proportions of propionate and branched-chain VFAs decreased (p < 0.05) with increasing stage of maturity. In conclusion, the ALKA-P could match the CONT-P in uCP and ME values and fermentation characteristics. Results for silages and their mixtures with concentrates highlight the importance of silage quality in dietary energy and protein supply for ruminants.
ABSTRACT
Supplementation of feed for bulls with selenium (+50%), vitamin D3 (+300%), vitamin E (+825%), vitamin K3 (+325%) and omega-3 fatty acids (+120%) affected beef nutrient composition. Twelve bulls (½â¯year old) were randomly allocated to two dietary treatments; control (Con) or supplemented (Sup), and fed 170â¯days pre-slaughter at an amount of 1% of body weight. Daily gain and feed efficiency were equal in the two groups. Homogenate meat from left forequarter in the Sup group contained more selenium (+26%), vitamin MK4 (+123%), D (+197%), E (+318%), and had lower omega-6/omega-3 ratio (-24%) compared to Con meat. Sup meat fulfilled the requirements to be labelled by health claims and nutrient claims as: "A food item containing a significant amount of selenium, vitamin K and vitamin D". We suggest supplementation of cattle rations during the finishing period as a strategy to increase meat content of specific nutrients important to human health.
