Effects of a combination of feed additives on methane production, diet digestibility, and animal performance in lactating dairy cows.
ABSTRACT Two experiments were conducted to assess the effects of a mixture of dietary additives on enteric methane production, rumen fermentation, diet digestibility, energy balance, and animal performance in lactating dairy cows. Identical diets were fed in both experiments. The mixture of feed additives investigated contained lauric acid, myristic acid, linseed oil, and calcium fumarate. These additives were included at 0.4, 1.2, 1.5, and 0.7% of dietary dry matter, respectively (treatment ADD). Experimental fat sources were exchanged for a rumen inert source of fat in the control diet (treatment CON) to maintain isolipidic rations. Cows (experiment 1, n=20; experiment 2, n=12) were fed restricted amounts of feed to avoid confounding effects of dry matter intake on methane production. In experiment 1, methane production and energy balance were studied using open-circuit indirect calorimetry. In experiment 2, 10 rumen-fistulated animals were used to measure rumen fermentation characteristics. In both experiments animal performance was monitored. The inclusion of dietary additives decreased methane emissions (g/d) by 10%. Milk yield and milk fat content tended to be lower for ADD in experiment 1. In experiment 2, milk production was not affected by ADD, but milk fat content was lower. Fat- and protein-corrected milk was lower for ADD in both experiments. Milk urea nitrogen content was lowered by ADD in experiment 1 and tended to be lower in experiment 2. Apparent total tract digestibility of fat, but not that of starch or neutral detergent fiber, was higher for ADD. Energy retention did not differ between treatments. The decrease in methane production (g/d) was not evident when methane emission was expressed per kilogram of milk produced. Feeding ADD resulted in increases of C12:0 and C14:0 and the intermediates of linseed oil biohydrogenation in milk in both experiments. In experiment 2, ADD-fed cows tended to have a decreased number of protozoa in rumen fluid when compared with that in control cows. Total volatile fatty acid concentrations were lower for ADD, whereas molar proportions of propionate increased at the expense of acetate and butyrate.
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ABSTRACT: The effect of Monensin (Rumensin, Eli Lilly & Co.) in incubations with mixed rumen microorganisms metabolizing carbohydrate or protein substrates was investigated. Monensin partly inhibited methanogenesis and increased propionate production, although the effect was not always statistically significant. Incubations with substrates specific for methane bacteria suggest that inhibition of methanogenesis by Monensin was not due to a specific toxic action on the methanogenic flora, but rather to an inhibition of hydrogen production from formate. Total and net microbial growth were considerably decreased by addition of Monensin, although the amount of substrate fermented was not altered, resulting in lowered values of microbial growth efficiency. In incubations with casein, Monensin lowered protein degradation in line with a lowered ammonia production, whereas a slight accumulation of alpha-amino nitrogen was observed. The results suggest that besides an influence of Monensin on the rumen carbohydrate fermentation pattern, another reason for the beneficial effects observed in vivo might be decreased food protein degradation in the rumen, altering the final site of protein digestion in the animal. Also, the possibility of a decrease in rumen microbial growth efficiency has to be considered when using Monensin as a food additive.Applied and Environmental Microbiology 10/1977; 34(3):251-7. · 3.68 Impact Factor
Article: Methane emissions from cattle.[show abstract] [hide abstract]
ABSTRACT: Increasing atmospheric concentrations of methane have led scientists to examine its sources of origin. Ruminant livestock can produce 250 to 500 L of methane per day. This level of production results in estimates of the contribution by cattle to global warming that may occur in the next 50 to 100 yr to be a little less than 2%. Many factors influence methane emissions from cattle and include the following: level of feed intake, type of carbohydrate in the diet, feed processing, addition of lipids or ionophores to the diet, and alterations in the ruminal microflora. Manipulation of these factors can reduce methane emissions from cattle. Many techniques exist to quantify methane emissions from individual or groups of animals. Enclosure techniques are precise but require trained animals and may limit animal movement. Isotopic and nonisotopic tracer techniques may also be used effectively. Prediction equations based on fermentation balance or feed characteristics have been used to estimate methane production. These equations are useful, but the assumptions and conditions that must be met for each equation limit their ability to accurately predict methane production. Methane production from groups of animals can be measured by mass balance, micrometeorological, or tracer methods. These techniques can measure methane emissions from animals in either indoor or outdoor enclosures. Use of these techniques and knowledge of the factors that impact methane production can result in the development of mitigation strategies to reduce methane losses by cattle. Implementation of these strategies should result in enhanced animal productivity and decreased contributions by cattle to the atmospheric methane budget.Journal of Animal Science 09/1995; 73(8):2483-92. · 2.09 Impact Factor
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ABSTRACT: Fat digestion and metabolism differ widely between animal species. In ruminants, dietary fats are hydrogenated in the rumen before intestinal absorption so that absorbed fatty acids (FA) are more saturated than dietary FA. In non-ruminants, intestinal FA digestibility depends on the level of saturation of dietary FA. Fat supplementation of the diet of cows decreases milk protein and has a variable effect on milk fat, depending on the source of dietary lipids. When encapsulated lipids are used, the linoleic acid content of milk is increased, but the organoleptic quality of milk may be altered. Supplementary lipids are incorporated into non-ruminant body fat, whereas de novo lipogenesis is reduced. There is a close relationship between the nature of dietary FA and nonruminant body FA.British Journal Of Nutrition 08/1997; 78 Suppl 1:S15-35. · 3.30 Impact Factor