work evaluating nutritional mitigation strategies. However, much of this work has been conducted on a small scale using intensive techniques such as respiration chambers or head boxes. Therefore, a method of gas collection and analysis was developed to allow evaluation of methane emissions by a large number of growing cattle under conditions that more closely mimic a production setting. The obj...

Gamma-aminobutyric acid (GABA), known as the most abundant inhibitory neurotransmitter in mammalian brain, can permeate ruminal epithelia by passive diffusion and enrich rumen environment. To explore whether addition of GABA regulate fermentation characteristics well methane production, a 2 × 6 factorial vitro batch culture was conducted to determine supplemental effect at inclusion levels 0 (C...

Microbial N produced in the rumen and flowing to the duodenum (Ni) is related to the total amount of OM fermented or apparently digested in the rumen (OMf). This relationship, best expressed as microbial N yield (gNi/kgOMf), is affected mainly by the physical and chemical properties of feed carbohydrates and the amounts ingested. These factors influence yields at three levels of increasing comp...

BACKGROUND The nature and amount of dietary medicinal plants are known to influence rumen fermentation and nutrient digestibility in ruminants. Nonetheless, changes in nutrient digestibility and rumen metabolism in response to dietary Andrographis paniculata (AP) in goats are unknown. This study examined the effects of dietary supplementation of leaves and whole plant of AP on nutrient digestib...

The rumen fermentation rates in individual lactating cows were measured in four different experiments. The results disclosed that the amounts and proportions of volatile acids formed could vary widely. In one case, a marked difference in the proportions of the acids produced arose within the experiment and correlated with a difference in the proportion of methane formed. The average rate of pro...

Newbold et al. (2006) and Calsamiglia et al. (2007) described essential oils (EO) as follows: volatile aromatic compounds with an oily appearance extracted from plant materials typically by steam distillation; alcohol, ester or aldehyde derivatives of phenylproponoids and terpenoids; some of the more common EO compounds available include thymol (thyme and oregano), eugenol (clove), pinene (Juni...

The study appraised the effects of Carotino oil on in vitro rumen fermentation, gas production, metabolism and apparent biohydrogenation of oleic, linoleic and linolenic acids. Carotino oil was added to a basal diet (50% concentrate and 50% oil palm frond) at the rate of 0, 2, 4, 6 and 8% dry matter of the diet. Rumen inoculum was obtained from three fistulated Boer bucks and incubated with 200...

The effects of ruminal ammonia concentration on bacterial numbers, fermentation pattern and degradation of feed ingredients in the rumen were examined with three nonlactating Holstein cows fitted with ruminal cannulas. Cows were fed twice daily a complete mixed diet (90% whole plant oat silage and 10% concentrate mixture) containing 11.1% CP on a DM basis. Ammonium bicarbonate (NH4HCO3) was inf...

Thiopeptin, thiopeptin-like antibiotics and penicillin were shown previously to be highly active in vitro against Streptococcus bovis, the microorganism believed to be responsible for the initiation of ruminal lactic acidosis. The purpose of this work was to determine the efficacy of these antibiotics in preventing lactic acidosis in lambs challenged by intraruminal administration of ground whe...

Studies on the quantitative significance of protozoa on carbon and nitrogen digestion and metabolism in the rumen were carried out in sheep given a diet of pelleted concentrate (500 g/d) and chopped hay (500 g/d). Measurements were made of apparent digestibility; flows of organic matter and dietary and microbial non-ammonia N (NAN) (using 15NH4+) to the duodenum; and rates of production, interc...