Ruminants feedlot

Schbnwiese (1995) calculates the CH share in the greenhouse effect of about 2.5% and agriculture is believed to account for roughly two-thirds of the total human-generated CH (Watson ef al. 1996). While paddy rice fields, cattle feedlots and the burning of biomass contribute to methane emissions, about 75% of methane on farms is emitted directly from ruminant animals, from digestive processes and excretion (Stolze ef al. 2000, Alfbldi ef al. 2002, Shepherd ef al. 2003). 

The FDA first approved use of a polyether ionophore as a feed additive for cattle in 1975. Ionophores were first isolated from bacteria generally of the S treptomyces genus, but are produced commercially by bacterial fermentation (qv). Monensin [17090-79-8] and other ionophores are being fed to over 90% of feedlot catde grown for beef (53) to enhance efficiency of gain improvements of 5—10% are common. Ionophores also are used as anticoccidial dmgs in poultry production and have similar, but lesser, effects in ruminants (54). 

McAllister MM, Gould DH, Raisbeck ME, Cummings BA and Loneragan GH (1997) Evaluation of ruminal sulfide concentrations and seasonal outbreaks of polioencephalomalacia in beef cattle in a feedlot. 1 Am Vet Med Assoc 211 1275-1279. 

Feedlot performance, carcass composition, and muscle and fat, CLA concentrations of lambs fed diets supplemented with safflower seeds. Small Ruminant Research, 49, 11-17. 

Under normal conditions, rumen fermentation produces gases that, by the action of ruminal and reticular contractions, accumulate in the area known as the cardia, from which they are passed up the oesophagus in the process of emctation. Bloat occm if the gas becomes trapped and the animal is not able to clear it. Rumen stasis due to acidosis is one of the causes of free gas bloat, but on certain pastures, particularly those rich in legumes, and on high-concentrate (feedlot) diets, the fermentation process in the rumen can result in rumen gases being trapped within fluid bubbles. Therefore, the gas cannot be eructated as normal and pressure builds up in the rumen. The condition is known as... 

Nitrate in farm wells is a common and especially damaging manifestation of nitrogen pollution from feedlots because of the susceptibility of ruminant animals to nitrate poisoning. The stomach contents of ruminant animals such as cattle and sheep constitute a reducing medium (low pE) and contain bacteria capable of reducing nitrate ion to toxic nitrite ion ... 

In ruminates, replacing soy meal with Camelina meal (2.04 kg of dry matter (DM)) in beef steer diets results in a marked reduction in stress response hormones (Cappellozza et al., 2012). Further, no changes in thyroid function are noted, but this meal reduces acute-phase reactive protein reaction, which is known to increase when cattle are transported or when cattle are introduced to a feedlot setting (Cappellozza et al., 2012). These results are indicative of a positive impact of Camelina meal in reducing stress response in cattle. In dairy cows, Camelina meal (2 kg of DM) results in a marked decrease in milk fat without an impact on total milk production (Hurtaud and Peyraud, 2007). Interestingly, inclusion of Camelina meal results in a marked increase in trans fatty acids, t-10 18 1 and t- 18 1, 11- and 2.6-fold, respectively, and a marked sevenfold increase in c-9, t-11 18 2 (conjugated linoleic acid). This may account for the enhanced spreadabiUty of butter made from milk derived from Camelina meal-fed cows (Hurtaud and Peyraud, 2007). Hence, in a limited number of studies, Camelina meal is observed to have a number of positive effects on the health of cattle, as well as in the parameters associated with milk production and quality. 

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