Effects of age on histological parameters of the sweat glands of Nellore cattle

The sweat glands are important in thermoregulation of cattle in a warm environment as they help dissipate heat through evaporation. Studies on gland histology are important to define its secretion potential and the capacity of perspiration and heat removal. The objective of this study was to determine, by histomorphometry, glandular epithelium height, the depth of the gland, length of the glandular portion and number of glands per cm2 of the sweat glands of the three age groups of Nellore cattle. Thirty females were used in this study. They were equally divided into calves, heifers and cows. Histological sections were obtained and analyzed by digital images in Trinocular BX40 Olympus microscope coupled to an Oly - 200 camera, connected to a computer. The images were obtained with microscope with 2x, 4x, 10x and 40x magnification objectives. The measurements were performed using HL Image 97 program. The height of glandular epithelium, depth of the glands, length and density of the glandular portion per cm2 , were all analyzed. The calves showed greater height of the glandular epithelium than heifers (P = 0.0024), and cows (P = 0.0191). The depth of the gland was not influenced by age. Cows had higher length of secretory portion than heifers (P = 0.0379) and calves (P = 0.0077). Heifers had a greater number of sweat glands per cm2 of skin than cows (P = 0.023). In cattle, the height of glandular epithelium and the density decreases as animals get older. On the other hand, the length of the secretor portion increases but with no changes in the depth of the sweat glands

Antibody response in cattle after vaccination with inactivated and attenuated rabies vaccines

Despite the absence of current official reports showing the number of cattle infected by rabies, it is estimated that nearly 30,000 bovines are lost each year in Brazil. In order to minimize the important economic losses, control of the disease is achieved by eliminating bat colonies and by herd vaccination. In this study, we compare the antibody response in cattle elicited by vaccination with an attenuated ERA vaccine (AEvac) and an inactivated-adjuvanted PV (IPVvac) vaccine. The antibody titers were appraised by cell-culture neutralization test and ELISA, and the percentage of seropositivity was ascertained for a period of 180 days. IPVvac elicited complete seropositivity rates from day 30 to day 150, and even on day 180, 87% of the sera showed virus-neutralizing antibody titers (VNA) higher than 0.5IU/ml. There were no significant differences between the VNA titers and seropositivity rates obtained with IPVvac in the two methods tested. AEvac, however, elicited significantly lower titers than those observed in the group receiving inactivated vaccine. In addition, the profiles of antirabies IgG antibodies, evaluated by ELISA, and VNA, appraised by cell-culture neutralization test, were slightly different, when both vaccines were compared.

Antimicrobial resistance and investigation of the molecular epidemiology of Listeria monocytogenes in dairy products

INTRODUCTION: Listeria monocytogenes is a ubiquitous microorganism in nature and is responsible for listeriosis, an infectious disease caused by consumption of contaminated food. METHODS: Molecular characterization was performed on 19 strains of Listeria monocytogenes (serovars 1/2a, 1/2b, 4b and 4c), isolated from dairy products in Rio Grande do Sul, Brazil. The molecular techniques applied were random amplification of polymorphic DNA and restriction enzyme analysis. In addition to the molecular analysis, the antimicrobial resistance profile was determined. RESULTS: The strains studied showed a low degree of diversity. In relation to the antimicrobial resistance profile of those microorganisms from the samples analyzed, all of them were susceptible to the antimicrobials tested. CONCLUSIONS: The molecular techniques that were used presented good discriminatory power for the strains studied. Furthermore, all of the samples that were analyzed were susceptible to the antimicrobials tested.

Nota sôbre um possível fator sub-letal em gado Holstein-Friesian

In this note the A. A. relate the occurrence of a possible sub-lethal factor, on the Holstein-Friesian herd of Escola Superior de Agricultura "Luiz de Queiroz", Piracicaba. The sire Horto was mated with his own mother, Brisa, and so, were obtained two calves, a male and a female, consecutively. Both the calves presented flexion and deviation of the fore legs. The sire's death has not alloved further observations. The study of these history cases excludes the mother's nutritional deficiency, as the cause of related phenomenon. In the consulted literature, VEIGA and MEAD et al. relate similar cases, although these are observed in other breeds of cattle The A. A. admit that cause of occurrence is a possible sublethal recessive factor, put in evidence by inbreeding.

Toxicological and toxicogenetic effects of plants used in popular medicine and in cattle food

Toxicological and toxicogenetic effects of aqueous (tea) and hexanica fruit extract of Indigofera suffruticosa Mill, and hydroalcoholic root extract od Solanum agrarium Stendt. Were evaluated in Balb C male mice intraperitoneally exposed. A hepatotoxic effect was observed just for animals treated with aqueous fruit extract of I. suffruticosa. In relation to the toxicogenetic effect, just the group trreated with 12.5% of toxic dose of aqueous fruit extract of I. suffruticosa showed a statistically significant increase in the frequency of cells with chromosome aberrations (cytogenetic effect), although a slight increase was also observed for the highest dose (25% of LF50_ of hydroalcoholic root extract of S. agrarium. The results obtanied show that before S. agrarium is used as medicine and before the wide use of I. suffruticosa in cattle food, careful evaluation must be done.

Cotylophoron travassosi sp.n. (Trematoda - Paramphistomidae) from cattle

A new species of the genus Cotylophoron (Trematoda - Paramphistomidae) - Cotylophoron travassosi sp. n. - is described. The measurements of the worm and its structures are compared with the valid known species.

Preliminary investigations on transmission and life cycle of the ear mites of the genus Raillietia trouessart (Acari: Gamasida) parasites of cattle

The life cycle of ear mites of the genus Raillietia Trouessart consists of egg, larva, proto-and deutonymph and adult. The proto-and deutonymph are free living, non feeding instars. The teneral adult is the transfer stage. The minimum period required for completion of the life cycle is approximately eight days.

The level of infestation with the vector of cattle babesiosis in Argentina

Studies were carried out to determine the differential aptitude to sustain the only vector of cattle babesiosis in Argentina, the tick Boophilus microplus, throughout the infested region of this country. Tick counts on Bos taurus cattle were used as the main criterion to classify favourable (F), intermediate (I) and unfavourable (U) areas for its development. The geographical limits of each area set up using data of non-parasitic tick stages, temperature, water balance and map recognition of flooded and unflooded zones. The F area contained 16.5 x 10 (elevado a sexta potência) ha with a cattle population of 6 x 10 (elevado a sexta potência); the I and U areas had 25 x 10 (elevado a sexta potência ha with 2.7 x 10 (elevado a sexta potência) cattle and 198 x 10 (elevado a sexta potência) with population of 2.4 x 10(elevado a sexta potência) cattle, respectively. Research on the relationship amongst Babesia-Boophilus-cattle is needed in the F area for tick development which coincides with the best region for cattle breeding.

Impact of Babesia bovis and Babesia bigemina on the production of beef cattle in Uruguay

Uruguay is situated in a marginal area for the development of Boophilus microplus (30- 35- South Lat.) with important areas of enzootic instability for Babesia bovis and B. bigemina. The livestock products represent 70% of our exports, for wich reason it is fundamental to evaluate the losses in the production that these haemoparasites cause as basic information to take future decisions. In the period 1988-1990, several works were carried out by our laboratory to know the incidence of babesiosis in the reduction of liveweight gains. The results are shown and discussed in the work. Experiment I: the weight increase of the control group (x = 0,248kg/day), was 23% higher than that of the infected group with Babesia spp (from Uruguay), but significant statistical differences were not found (P < 0,05). These animals were kept in boxes and the food was controlled for 76 days. Experiment II: the incidence of Babesis spp (same strain ) was studied for 140 on Hereford heifers (n = 14) on natural pastures. The control group obtained x = 25,29kg of liveweight gain and it was 45% higher than that of the infected group, significant statistical difference were found (P < 0,05). Experiments with attenuated strains III: four studies were carried out inoculating B. bovis and B. bigemina in bovines about one year old, in different growth systems, searching for the limit of application. Significant statistical differences between those groups were found during the experiment (about 180 days) (P < 0,05). Experiment combining and pathogenic strains IV: the liveweight gain, in immune and challanged group (n = 14) was the same than that of the unchallenged group and did not show significant statistical differences (P < 0,05). However the control challenged group had less weight gain and statistical differences were found (P < 0,05). Although this is a preliminary information, it shows that: (a) the incidence of babesiosis on the reduction of weight gains is important; (b) the decrease in weight gain was not observed when attenuated strains were used; when the challenge was done in immunized animals, losses in liveweight gain were not observed. These results are discussed in order to plan future studis in different real systems of production.

Succession and Abundance of Staphylinidae in Cattle Dung in Uberlândia, Brazil

Fimicolous Staphylinidae prey on rearing dipterous in cattle dung, acting as their natural controllers, including pests such as horn fly. To survey the abundance and succession of these coleopterans in cattle dung deposited in pasture, six experiments were conducted from March to October 1995 in Uberlândia, State of Minas Gerais, Brazil. Cattle dung pats were exposed at a pasture for 1 hr, 8 hr, 24 hr, 2, 3, 7 and 10 days and were than taken to laboratory separate from each other, for Staphylinidae extraction. A total of 156 dung pats were exposed at pasture, from which 6225 Staphylinidae were recovered. Representing at least 30 species. Staphylinidae sp.1 (29.6%), Philonthus flavolimbatus (22.2%), Heterothops sp.1 (16.6%), Oxytelus sp.2 (7.6%), Aleochara sp.2 (7.6%) and Criptobium sp.1 (4.4%) were the most abundant, representing 87.8% from the total. The increased frequency of the majority of these species along the dung exposition time at pasture, indicated tha, they would be preying on at all the immature stages of the dipterous, or eggs and first instar larvae of species that lay eggs on the dung after its second exposition day at the pasture

Immune response in cattle vaccinated against rabies

In order to determine the best type of rabies vaccine to use as a booster, 78 serological samples from singly vaccinated cattle were analyzed by counterimmunoelectrophoresis technique. The animals were divided into several groups, received the first vaccine dose with modified live virus vaccine (ERA strain) and were revaccinated with inactivated virus or modified live virus vaccines. Boosters were given at 2, 4, 8, 12 and 16 weeks following first vaccination. Results showed high titres in the cases of booster with inactivated vaccine. In all cases, however, detectable antibody titres declined quickly.

Detection of poxvirus in cattle associated with human cases in the State of Rio de Janeiro: preliminary report

This preliminary report describes human and cow cases of poxvirus that recently ocurred in the State of Rio de Janeiro. The electron microscopic findings were consistent with parapoxviral and orthopoxviral infection. Orthopoxvirus strains were isolated from human and cow cases. Detailed viral characterization by means of genetical techniques is under investigation. Based on these informations, poxviral diseases should be also considered an emerging viral zoonosis that can affect human beings.

Development of an enzyme-linked immunosorbent assay for detection of IgM antibodies to Babesia bigemina in cattle

A crude antigenic preparation of Babesia bigemina was used to develop an ELISA for the detection of IgM antibodies. Optimal dilutions of the antigen, using positive and negative reference sera, were determined by checkerboard titrations. Negative sera from cattle imported from tick-free areas, serum samples collected from infected B. bigemina cattle were used to validate the test. The specificity was 94% and sensitivity of the Elisa 87.5%. Sera from 385 cattle deriving from areas free from tick-borne diseases, which were submitted to a preimmunization process, were screened by this technique. The Elisa detected seroconversion on the 14th day post-inoculation in animals either infested with Boophilus microplus ticks (infected with B. bigemina), or inoculated with B. bigemina infected blood. Antibody titers decreased after day 33; however, all animals remained positive until the end of the experiment (124 days). The ELISA described may prove to be an appropriate serological test for the detection of IgM antibodies against B. bigemina.

Dynamics of Haematobia irritans irritans (Diptera: Muscidae) infestation on Nelore cattle in the Pantanal, Brazil

From June 1993 to May 1995, horn fly counts were conducted twice a month on untreated Nelore cattle raised extensively in the Pantanal. Horn fly population showed a bimodal fluctuation and peaks were observed every year after the beginning (November/December) and at the end (May/June) of the rainy season, which coincided with mid-late spring and mid-late fall, respectively. Horn flies were present on cattle throughout the year in at least 64% of the animals. Mean horn fly numbers on animals did not exceed 85 flies/cow during peaks and were under 35 flies/cow in most of the remaining periods. The highest infestations (population peaks) were short and dropped suddenly within two weeks. Less than 15% of the animals in both herds could be considered as "fly-susceptible" - showing consistently higher infestations, or "fly-resistant" - showing consistently lower infestations.