A. R. Abou Akkada

Effect of ruminal infusion of acetic acid and sodium acetate on the concentrations of ciliate protozoa

Two fistulated rams were infused through the rumen cannulae with acetic acid or sodium acetate for 4 consecutive days. This infusion has caused a significant drop in the daily feed intake and in the concentrations of rumen ciliate protozoa. The holotrich protozoa were the most susceptible, whereas entodinia were the least sensitive, to the reducing effect of acetic acid or sodium acetate. Decreasing the daily feed intake by 30% has caused little or no change in the concentrations of rumen ciliate protozoa. The in vitro incubation of sodium acetate and rumen contents has resulted in a remarkable depression in the protozoal numbers. Most of this decrease occurred after 5 h of incubation. The addition of acetic acid or sodium acetate to washed suspensions of mixed populations of rumen ciliate protozoa has decreased the in vitro volatile fatty acid production. It is suggested that both the low pH and acetate, ion were responsible for the reduction in the protozoal numbers in the rumen of rams infused with acetic acid or sodium acetate. The effect of acetate on the ciliate protozoa could be an explanation of the diurnal changes in the concentrations of various protozoal groups usually observed in the rumen of the host animal.

Farming Systems Producing Livestock in Mediterranean Areas

The major farming systems producing livestock in Mediterranean areas can be classified into four groups: nomadic herding; transhumant farming; rainfed farming; and irrigated farming. In these systems the animal resources and the feed resources closely interact. In a study of seven Mediterranean countries it was found that small ruminants account for 25% of the total ruminant population, and that natural rangeland and dry roughages account for 75% of the total feed resources, while large ruminants could only be fed by the irrigated farming systems of Morocco and Egypt. The farming systems in these seven countries have generated three livestock feeding systems: extensive; integrated with arable crops; intensive. In mixed farming systems interactions between crops and livestock often have major impact on the productivity and efficiency of these systems.

Effect of environmental temperature on ruminal activity and blood urea of Merino sheep.

Eight Merino wethers were used in an experiment designed to study the effect of heat stress on ruminal activity and blood urea of sheep newly introduced to Egypt. The sheep were exposed to 15° and 35°Cin aclimatic chamberwith controlled temperature and humidity. The animals were divided into two groups; the first received 100% of the TDN daily requirement and the second was given 125% of the recommended TDN. Rumen and blood samples were obtained from the animals before and at 2, 4, 6, 8 and 10 hr after feeding. VFA concentrations in the rumen were higher in sheep fed on rations of high energy content. The levels of VFA at the low temperature were greater than at the high temperature. Ruminal ammonia and blood urea N concentrations in sheep maintained at the low temperature (15°C) were higher than those of the same animals when kept at the high temperature (35°C). This trend was more obvious at high levels of energy intake. It is suggested that the significant changes in rumen VFA, ammonia N and blood urea N in Merino sheep maintained under hot conditions can be considered as adjustments to changes in nutritional requirements in response to high environmental temperature.