Evaluation of endotoxaemia in the prognosis and treatment of scouring merino lambs

Familiar hypopigmentation syndrome in sheep associated with homozygous deletion of the entire endothelin type-B receptor gene

In humans, rodents and horses, pigmentary anomalies in combination with other disorders, notably intestinal aganglionosis, are associated with variants of the endothelin type-B receptor gene (EDNRB). In an inbred Cameroon sheep flock, five white lambs with light blue eyes were sired from the same ram and died within a few hours up to a few days after birth, some of them with signs of intestinal obstruction. The aim of this study was to investigate if the observed hypopigmentation and a possible lethal condition were associated with a molecular change at the ovine EDNRB locus, and to check if such a genetic alteration also occurs in other Cameroon sheep flocks. Sequence analysis revealed a deletion of about 110 kb on sheep chromosome 10, comprising the entire EDNRB gene, on both chromosomes in the two available hypopigmented lambs and on a single chromosome in the two dams and three other unaffected relatives. This micro-chromosomal deletion was also confirmed by quantitative real-time PCR and by fluorescence in situ hybridization. Genotyping of a total of 127 Cameroon sheep in 7 other flocks by duplex PCR did not identify additional carriers of the deletion. Although both hypopigmented lambs available for post-mortem examination had a considerably dilated cecum and remaining meconium, histopathological examination of intestinal samples showed morphologically normal ganglion cells in appropriate number and distribution. This is to our knowledge the first description of an ENDRB gene deletion and associated clinical signs in a mammalian species different from humans and rodents. In humans and rats it is postulated that the variable presence and severity of intestinal aganglionosis and other features in individuals with EDNRB deletion is due to a variable genetic background and multiple gene interactions. Therefore the here analyzed sheep are a valuable animal model to test these hypotheses in another species.

Treatment and control of respiratory disease in sheep

Respiratory diseases in sheep result in poor live weight gain and mortality, thus causing considerable financial losses for lamb producers. The disease is also an important animal welfare concern. Respiratory diseases in sheep and goats often result from adverse weather conditions and physiologic stress combined with viral and bacterial infections. It is essential to critically assess clinical diagnostic methods, treatment options, and control measures for the common respiratory diseases affecting sheep.

Treatment of calf diarrhea: antimicrobial and ancillary treatments

Adjunct treatment of diarrhea should be routinely undertaken in all calves with systemic signs of illness, manifest as fever, inappetance, or lethargy. Ancillary treatments with documented efficacy in undifferentiated calf diarrhea include parenteral administration of antimicrobials with a predominantly gram negative spectrum of activity, parenteral administration of non-steroidal anti-inflammatory agents such as meloxicam and flunixin meglumine, and continued feeding of cow's milk. Halofuginone and azithromycin have efficacy in calves with diarrhea due to Cryptosporidium parvum, and their administration should be considered in calves documented or suspected to have cryptosporidiosis.

Relationship between the treatment and the evolution of the clinical course in scouring Merino lambs from "La Serena" (Southwest Spain)

This work investigated the link between the type of treatment and the clinical evolution of lambs suffering from diarrhoea attributed to non-enterotoxigenic Escherichia coli. Two hundred and forty scouring lambs, and 25 healthy lambs selected as control, were used in this trial. The faecal samples from the scouring lambs were positive to non-enterotoxigenic E. coli. All the scouring lambs received supportive care and they were randomly allotted to two groups of 120 animals (treated group and untreated group). The lambs in the treated group were given two daily doses of 20 mg/kg live weight spectinomycin for 3 days, while the other group of lambs (untreated group) did not receive any antibiotic. Serum endotoxin was higher in the treated lambs. The combined infection of E. coli + Proteus mirabilis was the most frequent microbiological result in the deceased treated lambs, while the only enteric pathogen isolated in the untreated lambs submitted to necroscopy was E. coli. The pathological findings most commonly recorded in the untreated lambs were suggestive of a generalized inflammatory process attributed to colibacilosis, while the lesions in the treated lambs might correspond to an enterotoxoemic process. The overproduction of P. mirabilis might be consequence of the antibiotic treatment and it would be the most probable cause of the endotoxemia, the high mortality rate and the pathological findings in the treated lambs. Therefore, a supportive care without antibiotics does not lead to a poorer chance of survival in lambs with diarrhoea attributed to non-enterotoxigenic E. coli.