Heartwater. An overview of the clinical signs, susceptibility and differential diagnoses of the disease in domestic ruminants

Heartwater is a frequently fatal tick-borne disease of ruminants caused by Cowdria ruminantium. In domestic ruminants the incubation period varies considerably and depends on the route of infection, virulence of the isolate and amount of infective material administered. Adult cattle of all breeds appear to be equally susceptible to heartwater. It is generally accepted that calves up to the age of 3 weeks have a high degree of natural resistance which is not related to the immune status of the dam. Nervous symptoms are frequently seen in animals affected by the peracute and acute forms of heartwater and can easily be confused with similar signs caused by infectious conditions, toxic plants, acaricide and heavy metal poisonings.     

Excretion of alcelaphine herpesvirus-1 by captive and free-living wildebeest (Connochaetes taurinus)

Excretion of alcelaphine herpesvirus-1 (AHV-1) is for all practical purposes limited to wildebeest calves under the age of 4 months. Sixty-one per cent of calves 1-2 months of age excreted virus with a mean titre of 9.8 X 10(4) cytopathic-forming foci/ml in their ocular fluid. The incidence declined sharply to less than 2% in wildebeest older than 6 months. No difference in age-related excretion of virus could be detected between free-living and captive wildebeest and no virus could be isolated from free-living pregnant wildebeest cows or from captive cows and their calves during the first 4 weeks after birth. The occurrence of wildebeest-derived malignant catarrhal fever (WD MCF) during spring, when wildebeest do not excrete virus, is a strong indication of the existence of an alternative host or an intermediate host capable of biological transfer of AHV-1.     

Failure of a recombinant Babesia bovis antigen to protect cattle against heterologous strain challenge

Groups of cattle were inoculated subcutaneously with (i) a recombinant DNA-derived Babesia bovis protein (KaBbl-GZ) fused to beta-galactosidase and combined with adjuvants, or (ii) native beta-galactosidase (GZ) plus adjuvant, or (iii) adjuvant only or (iv) a live, attenuated B bovis vaccine. KaBbl-GZ was produced in the lambda gt11-amp3 system as a 5-10 kD babesial polypeptide linked to GZ. KaBbl has previously been shown to be an immunodominant antigen of B bovis, localised at the apex of the parasite, and present in a range of B bovis strains. High levels of GZ antibodies were observed in KaBbl-GZ and GZ inoculated cattle, but specific KaBbl antibodies could not be detected by ELISA. Five months after primary inoculation, all cattle were blood challenged with a virulent heterologous B bovis strain. Despite four inoculations with KaBbl-GZ, significant protection against the challenge was not observed.     

The composition of adipose tissue and its usefulness as a parameter for carcass composition in growing pigs

Growing pigs, varying in body weight between 25 and 110 kg, showed differences in fat content between adipose tissues from different body sites. In all adipose tissues fat content increased during growth; the increase in fat content was, as shown for backfat, affected by the level of daily energy intake. It is concluded that the dry matter (DM) or fat content in a single sample of adipose tissue cannot be used as an accurate parameter for fatness of carcasses at a normal slaughter weight.     

Modificaciones ponderales y estructurales de la glándula submaxilar de rata, en respuesta a diversos estímulos incisales

A study of the influence of dietary alterations and extraction or amputation of the incisor teeth in young male rats is interpreted in light of a hypothesis concerning the mechanisms of control of mandibular salivary gland growth     

Survey of internal parasites in Western Australian pig herds 2. Relationship to anthelmintic usage and parasite control practices

The housing, management and internal parasite control practices used in piggeries in Western Australia was surveyed by interviewing the owner/manager of 100 randomly selected piggeries. At the time of the interview 20 faecal samples were collected from pigs and examined for evidence of internal parasites. Most herds (80%) in which anthelmintics were used, had evidence of nematode infection. Some pig producers were using an anthelmintic that was ineffective against nematode species present while some herds had nematodes that should have been controlled by the anthelmintic being used. Prevalence of nematode infection was higher in pigs run in paddocks than in pigs housed intensively. Washing sows prior to farrowing was associated with a lower prevalence of nematode infection. The findings suggested that pig producers should ensure that the anthelmintic used is effective against the nematodes present in their pigs. It was concluded that administering anthelmintics as a single dose in the feed may not be the most effective method of deworming pigs.