Porcine circovirus 2-associated disease in Eurasian wild boar.

Porcine circovirus 2 (PCV2) was first identified in high-health herds of domestic swine and was associated with a debilitating disease called postweaning multisystemic wasting syndrome (PMWS). Most subsequent studies have indicated that PCV2 infects only swine but there is little information on porcids other than improved breeds of domestic swine. Multisystemic disease was reported in a group of Eurasian wild boars raised under free-range conditions. Affected young pigs had pneumonia and enteritis and were cachectic. Porcine circovirus 2 was identified in affected tissue by immunohistochemistry and in situ hybridization, and a PCV2-like virus was isolated from pooled organs. The open reading frame (ORF2) of the isolated PCV2 had a 98.7% homology with the ORF2 of a reference PCV2 isolate. These diagnostic data indicate that PCV2 can infect and cause disease in Sus scrofa subspecies other than domestic swine.     

Rocky Mountain spotted fever in an urban canine population

A survey for the prevalence of Rocky Mountain spotted fever antibodies in dogs from a well-defined endemic area in Columbus, Ohio (Franklin County), was conducted during the summer of 1981. Seventy-three blood samples from dogs in this area were tested by microimmunofluorescence for antibodies to Rickettsia rickettsii and other rickettsial antigens. Thirty-three (45.2%) of these samples were positive for R rickettsii, with titers ranging from 1:8 to 1:2,048. For comparison, 137 blood samples from dogs at the Franklin County Dog Pound also were tested. One dog (0.7%) from the comparison group was seropositive to R rickettsii, with a 1:64 titer. The results indicated a nidus of this disease within the city of Columbus, Ohio.     

Absence of evidence of porcine circovirus infection in piglets with congenital tremors.

Porcine circovirus types 1 (PCV1) and 2 (PCV2) have been associated with congenital tremors (CTs) in piglets in the United States. In this study, central nervous system and nonneural tissues of 40 CT piglets from Spain, the United Kingdom, Ireland, and Sweden were investigated for the presence of PCV1 and PCV2 using in situ hybridization and immunohistochemical labeling on paraffin sections. The polymerase chain reaction for PCV2 was also carried out on sera from the Spanish CT cases. No evidence of circovirus nucleic acid or antigen was found in any CT piglet. Although these results do not support the hypothesis that PCV1 or PCV2 are linked to porcine CT, they cannot disprove it.     

Development of a gonadotrophin-releasing hormone and prostaglandin regimen for the planned breeding of dairy cows

Four studies were carried out to determine the ovarian responses of dairy cows undergoing natural oestrous cycles to sequential injections of gonadotrophin-releasing hormone (GnRH), followed seven days later by prostaglandin and, 48 to 72 hours later, by a second injection of GnRH. In study 1, of 60 cows so treated, 47 were in the intended periovulatory phase when a fixed-time insemination was given 72 hours after the prostaglandin. In study 2, detailed observations were made in 32 cows treated as in study 1, using ultrasound to determine the optimum time to administer the second dose of GnRH. Ovulation was most effectively synchronised by giving GnRH 56 to 60 hours after the prostaglandin. Study 3 investigated the timing of ovulation when no initial dose of GnRH was given. Six cows were injected with prostaglandin on day 12 of the oestrous cycle, followed by GnRH 60 hours later. Five of the six cows ovulated 24 to 36 hours after GnRH, an equivalent timing and synchrony to that in study 2, in which a dose of GnRH had been given seven days before prostaglandin. In study 4, an initial dose of GnRH was given to six cows late (day 17) in the oestrous cycle, and prostaglandin seven days later. The GnRH treatment delayed luteolysis in five of the cows so that they were responsive to the prostaglandin and ovulated 24 to 36 hours after the second dose of GnRH. The use of GnRH (day 0) - prostaglandin (day 7) - GnRH (day 9.5) appears to be an effective means of synchronising ovulation in most cows.     

Ovarian and hormonal responses of cows to treatment with an analogue of gonadotrophin releasing hormone and prostaglandin F2 alpha

Blood samples were taken from 11 cows and their ovaries were scanned by ultrasound at least daily. Around day 5 of an induced cycle, they were injected with 10 micrograms buserelin, an analogue of gonadotrophin releasing hormone, and on day 12 they received 0.5 mg cloprostenol, an analogue of prostaglandin F2 alpha (PGF2 alpha). Two days later six of the cows (the treated group) received a second injection of 10 micrograms buserelin, but the remaining five received no further treatment (control group). The dominant, that is, the largest follicle in each cow disappeared after the first buserelin injection and was replaced by a new one which grew synchronously in all the cows until after the treatment with PGF2 alpha. Ovulation occurred significantly earlier after PGF2 alpha in the treated group than in the control group (72 to 96 hours v 96 to 120 hours; P < 0.05). Plasma progesterone concentrations then increased more rapidly in the treated group than in the control group and were significantly higher on days 3 and 4 after ovulation (P < 0.05).