Risk factors for trypanosomiasis by Trypanosoma vivax in cattle raised in Rio Grande do Norte state

ABSTRACT: The objective of this study was to determine the prevalence of anti Trypanosoma vivax antibodies and the possible risk factors associated with the infection in cattle in Rio Grande do Norte, Northeastern Brazil, through a cross-sectional epidemiological study, with non-probabilistic convenience sampling. A total of 467 cattle’s serum samples were analyzed by indirect immunofluorescence. Forty-two samples tested positive for Trypanosoma vivax IgG antibodies, corresponding to the prevalence of 9%. Risk factors influencing the occurrence of trypanosomiasis were milk exploration, raising of European breeds, productivity category: lactation cow, purchase of new cattle, foraging habits near ponds and rivers, and the presence of mechanical vectors. So, high prevalence in beef animals (59.5%), females (95.2%), European breed (88.1%), lactating cows (85.7%), pasture at banks of dams and rivers (95.2%), in addition to the presence of mechanical vectors (81%) and acquisition of animals (88.1%), indicates the expansion of trypanosomiasis in Northeastern semi-arid region, and the information obtained may explain the epidemiological factors that determine the occurrence of trypanosomiasis by T. vivax in this region.

Economic effects of alternate growth path, time of calving and breed type combinations across southern Australian beef cattle environments: feedlot finishing at the New South Wales experimental site

The ‘Regional Combinations’ project and its biophysical outcomes have been described in several other papers in this special edition. The information provided in these papers allows an evaluation of the most profitable beef cattle production systems across different environments in southern Australia. In this paper, the focus is on the New South Wales experimental site where the trial animals were finished in a feedlot. The data identified liveweight gain as the biggest driver of profitability of production. Between growth treatments, there was a large difference in the gross margins before feedlot entry between the ‘fast’ and ‘slow’ treatments favouring the fast-grown animals, even after accounting for the higher cost of producing pasture capable of sustaining faster growth. However, the slow growth treatments consistently outperformed the fast growth treatments in the feedlot. In terms of breeds, the European breed types consistently outperformed the Wagyu breeds. There were no time-of-calving experiments in New South Wales.

Effect of Duration of Fasting and a Short-Term High-Roughage Ration on the Concentration of Escherichia coli Biotype 1 in Cattle Feces

A field trial using cattle from a commercial feedlot was conducted to quantify the effect of duration of fasting and a temporary change in ration on the concentration of Escherichia coli biotype 1 in feces. A nested hierarchical design with repeated measures through time was used. Two groups of 20 British × European breed beef steers having reached slaughter weight (mean live weight 685 kg; SD 50 kg) were fed entirely on a high-energy ration typical of that used in the Ontario beef finishing industry or were switched for 4 days onto a high-roughage ration. This was followed by a period of fasting and water deprivation to mimic that which occurs prior to slaughter. Fecal samples were collected at 0, 24, and 48 h of fasting, and for each sample the total presumptive E. coli (biotype 1) CFU/g of feces was enumerated by spiral plating. Estimates of effect for the design factors were obtained by restricted maximum likelihood, and these were compared to robust counterparts obtained from generalized estimating equations. Results indicated that the ration, the duration of fasting, and their interaction had significant effects on total log E. coli concentration in feces. Cattle on the high-roughage ration for four days had a significantly lower initial log E. coli CFU/g of feces compared to cattle on the normal ration, but after 48 h of fasting they had a significantly higher concentration. It is concluded that while a temporary change in ration and duration of fasting does affect E. coli concentration in feces, these changes do not seem large enough to deliver a drastic improvement in beef carcass hygiene should they be incorporated in hazard analysis and critical control point (HACCP) plans for the preslaughter period of beef production.

The Hungarian Grey cattle: a traditional European breed

SummaryIn this paper, the Hungarian Grey, a traditional draught and beef cattle was studied. This breed was threatened by extinction due to the mechanization of agriculture and propagation of upgraded breeds which had almost completely replaced it. Following a crisis in the 1960's (in 1966 only 470 dams were registered) a pioneering conservation scheme was introduced. Thanks to scientific breeding, the number of cows increased to approximately 1 600 and the risk of inbreeding has been avoided. In addition to a historical review, body conformation, production characteristics and modern forms of exploitation for this rare but genetically valuable breed are discussed.

The ability of Rhipicephalus appendiculatus (Acarina: Ixodidae) stocks in Kenya to become infected with Theileria parva

Eight steers of European breed, Bos taurus type which were shown to be negative for antibodies against Theileria parva, were divided into two groups of four animals each. Animals in one group were inoculated with 0.5 ml undiluted tick-derived T. p. parva Muguga strain and animals in the other group were inoculated with 1 ml undiluted tick-derived T. p. parva Kilae strain to infect them. The two infected groups of cattle were simultaneously infested with uninfected nymphal Rhipicephalus appendiculatus Neumann in separate cloth patches. Ticks were from five populations, i.e., four from different geographical zones in Kenya and one laboratory population, in separate cloth patches. After moulting, the adult ticks were fed on rabbits for three days and their salivary glands were examined by microscopy for infective stages of the parasite. This revealed significant differences in the five populations as regards to their susceptibility to Theileria parva parasites.

The comparative digestive powers of zebu and high-grade European cattle

1. With three different groups, each of two zebu and two zebu × Ayrshire grade oxen, and ten typical East African feeding stuffs, no significant difference was found between the average digestibility coefficients recorded with the zebu and the grade oxen.2. The slight differences in feeding values were also of no practical significance.3. Some of the zebu × Ayrshire cattle were 3/4 and others 7/8 Ayrshire but the higher grading to the European breed apparently did not affect the digestive powers.