Carcass and Meat Characteristics of Bulls from Arsi, Boran, Harar and Holstein Frisian Crosses Cattle Breeds Finished under Similar Level of Concentrate Supplementation

A study was conducted to evaluate the effect of age and breeds (Arsi, Borana, HF-Cross and Harar) on carcass and meat characteristics of bulls finished under similar feeding conditions. The feeding experiment was conducted for 90 days at Beef farm of Haramaya University. In this experiment, 24 bulls were fed with roughage (60%) which contained grass hay and wheat straw and concentrate (40%) which contained wheat bran, noug (gucia abysica) cake, maize grain, limestone, salt and ruminant premix. The bulls were transported to Bishoftu ELFORA export abattoir for slaughter following the procedure of the abattoir. The result of the study revealed that the average slaughter weight, hot carcass weight, cold carcass weight, shrink loss, commercial dressing and true dressing percentage were 179.1 kg, 86.8 kg, 82.7 kg 4.7%, 48.8% and 78.3%, respectively. Total edible and nonedible offal were significantly (P < 0.01) influenced by breed and age. Pelvic fat was significantly (P < 0.01) influenced by breeds. Meat yield percentages of Arsi, Boran, Harar, and HF-crossbred were 78.1%, 77%, 72.8% and 77.2% respectively. Meat yield was predicted from fat thickness and ribeye area with 61% accuracy. Arsi bulls attained the highest (78%) meat yield at early age but decreased by 0.713 rate as age of animals advanced by one digit whereas the meat yield from other breeds showed increment in meat yield percentage with the rate of 1.98, 1.1 and 0.1 for cross, Borana and Harar breed bulls, respectively as age advanced. Yield from fore shank, sirloin, top and bottom sirloin primal cuts were affected by breed. Arsi breed had higher meat bone ration than cross breed. Retailed meat yield was significantly (P < 0.001) predicted from rib area and subcutaneous fat thickness (P < 0.001) with a coefficient of determination 61%, from live animal trait and primal cuts with a coefficient of determination 89.56% and 94.78% respectively. Arsi bulls can be used for beef purpose at 2 - 3 years, as the meat percentage decreases thereafter;while bulls from Boran, cross breed and Harar breeds can be used up to 5 years of age. Meat to bone ratio indicated that HF-Crossbred was less appropriate for beef purpose than other breed bulls in this study. The rate of pH decline was not influence (P > 0.05) by age and breed in the current study.

Dietary Coleus amboinicus Lour. decreases ruminal methanogenesis and biohydrogenation, and improves meat quality and fatty acid composition in longissimus thoracis muscle of lambs

Background:Methane production and fatty acids(FA)biohydrogenation in the rumen are two main constraints in ruminant production causing environmental burden and reducing food product quality.Rumen functions can be modulated by the biologically active compounds(BACs)of plant origins as shown in several studies e.g.reduction in methane emission,modulation of FA composition with positive impact on the ruminant products.Coleus amboinicus Lour.(CAL)contains high concentration of polyphenols that may potentially reduce methane production and modulate ruminal biohydrogenation of unsaturated FA.This study aimed to investigate the effect of BAC of Coleus amboinicus Lour.(CAL)fed to growing lambs on ruminal methane production,biohydrogenation of unsaturated FA and meat characteristics.In this study,the in vitro experiment aiming at determining the most effective CAL dose for in vivo experiments was followed by two in vivo experiments in rumen-cannulated rams and growing lambs.Experiment 1(RUSITEC)comprised of control and three experimental diets differing in CAL content(10%,15%,and 20%of the total diet).The two in vivo experiments were conducted on six growing,rumen-cannulated lambs(Exp.2)and 16 growing lambs(Exp.3).Animals were assigned into the control(CON)and experimental(20%of CAL)groups.Several parameters were examined in vitro(pH,ammonia and VFA concentrations,protozoa,methanogens and select bacteria populations)and in vivo(methane production,digestibility,ruminal microorganism populations,meat quality,fatty acids profiles in rumen fluid and meat,transcript expression of 5 genes in meat).Results:CAL lowered in vitro methane production by 51%.In the in vivo Exp.3,CAL decreased methane production by 20%compared with the CON group,which corresponded to reduction of total methanogen counts by up to 28%in all experiments,notably Methanobacteriales.In Exp.3,CAL increased or tended to increase populations of some rumen bacteria(Ruminococcus albus,Megasphaera elsdenii,Butyrivibrio proteoclasticus,and Butyrivibrio fibrisolvens).Dietary CAL suppressed the Holotricha population,but increased or tended to increase Entodiniomorpha population in vivo.An increase in the polyunsaturated fatty acid(PUFA)proportion in the rumen of lambs was noted in response to the CAL diet,which was mainly attributable to the increase in C18:3 cis-9 cis-12cis-15(LNA)proportion.CAL reduced the mRNA expression of four out of five genes investigated in meat(fatty acid synthase,stearoyl-CoA desaturase,lipoprotein lipase,and fatty acid desaturase 1).Conclusions:Summarizing,polyphenols of CAL origin(20%in diet)mitigated ruminal methane production by inhibiting the methanogen communities.CAL supplementation also improved ruminal environment by modulating ruminal bacteria involved in fermentation and biohydrogenation of FA.Besides,CAL elevated the LNA concentration,which improved meat quality through increased deposition of n-3 PUFA.Highlight·Coleus amboinicus Lour.(CAL)into sheep diet decreased CH4emission.·CAL did not reduce nutrient digestibility,but inhibited the methanogen community.·CAL increased ruminal propionate proportion and decreased acetate/propionate ratio.·CAL elevated n-3 fatty acid concentration in ruminal fluid and meat.·Supplementation of CAL improved some meat quality traits.