No abstract

The effect of drastic undernutrition was studied in Bos indicus cows. Four nonlactating cows (body weight = 208 kg) fitted with ruminal cannulas were used in a crossover design. They received, in two 1-mo periods, a diet of 80% rice straw and 20% cotton-seed meal fed either at energy maintenance [3.91 kg of dry matter (DM)/d] or at one-third of this intake (1.30 kg of DM/d). The variation in digestibility was studied in relation to particle retention time and microbial events. Organic matter digestibility decreased with underfeeding (64.5 and 53.7%, respectively, at high and low intakes) without modification of mean ruminal or total tract retention times. This lower digestibility can be related to a decrease in protozoal population in the rumen; however, other characteristics of microbial activity did not vary, such as in situ DM degradability (41.9 and 43.3%, respectively, at high and low intakes) and ruminal soluble Ca concentration, a factor involved in the attachment of microorganisms to feed particles. Mean size of ruminal particles was not modified, although more time spent chewing was observed at the low intake (165 and 221 min/kg of DM intake, respectively, at high and low intakes). This experiment confirms that, at intakes below maintenance, digestibility can decrease when feed intake is restricted, contrary to the general view described in the literature.

Abstract:Background: Brucellosis is an important zoonotic disease in developing countries yet it is often not recognized, goes unreported and does not attract public health action by these governments including Uganda. Objective: To estimate the sero-prevalence and assess modifiable risk factors associated with Brucella seropositivity in cattle keepers and consumers of unpasteurized milk in Uganda. Methods: One group comprised of 161 individuals randomly selected from households living on farms that had Brucella sero-positive cattle and/or goats in Mbarara District from an earlier survey; the second group comprised of 168 randomly selected individuals attending an HIV voluntary counseling and testing clinic in Kampala District. Sera samples were tested using Rapid Plate Agglutination Test, Standard Tube Agglutination Test and cELISA. Results: The sero-prevalence of brucellosis among exposed cattle keepers in Mbarara and consumers of unpasteurised milk in Kampala Districts was 5.8% (95%CI: 3.3%, 8.3%) and 9% (95%CI: 13.3%, 4.7%), respectively. Consumption of unboiled milk was significantly (p=0.004) associated with seropositivity in Mbarara District. There was no association between sero-positivity with age, sex and awareness of human brucellosis. Conclusion: Human brucellosis is prevalent among livestock rearing communities and consumers of unpasteurised milk. The continued consumption of unboiled milk is a major health risk.

The effect of extended underfeeding on digestion was studied in dairy cows. Four nonlactating cows (BW = 747 kg) were first fed a forage-based diet at a level above energy maintenance requirements for 7 wk (9.4 kg DM/d) then were restricted at a low level of intake of the same diet for 5 mo (5.2 kg DM/d), then refed at the first level. Digestion measurements were made before and after the underfeeding period, and at 1, 5, 9, and 19 wk of underfeeding. Organic matter digestibility decreased with underfeeding then increased (62.7, 56.2, and 61.5% before, 1 wk after, and 19 wk after underfeeding, respectively). Differences in ruminal apparent OM digestion were nonsignificant (P > .05). This lack of difference was related to the absence of variation of ruminal particle passage rate and DM degradability measured in situ. However, the decrease in feed intake decreased ruminal (P < .01) and intestinal (P < .05) liquid dilution rates, ruminal DM pool size and DM content (P < .01), and protozoa concentration (P < .01). The decrease (P < .01) in N retention with underfeeding was followed by an increase (P < .05) during the underfeeding period, due to a decrease in fecal and urine N losses. This experiment has shown an unusual and temporary response of digestion to underfeeding. Knowledge of adaptation of digestion to low intakes needs to be improved.