Plasma Cortisol Concentrations after CIDR Insertion in Beef Cows

The objective of this study was to show plasma cortisol concentration after treatment with controlled internal drug release (CIDR) in non‐suckling beef cows. On day 9 after oestrus, two cows were inserted with CIDR into the vagina for 24 h and the other two cows were treated as a control group. Four days later, the two control cows were treated with CIDR and the other two CIDR‐treated cows were used as controls. Cortisol concentrations were determined by ELISA in plasma samples collected before, during and after insertion of CIDR. There was a significant increase in plasma cortisol concentrations (p < 0.01) after insertion of CIDR. Mean (±SEM) plasma cortisol concentrations increased from 1.3 ± 0.4 to a peak of 8.8 ± 1.1 ng/ml at 5 h and then decreased to basal concentrations at 7 h after insertion of the device. In conclusion, the insertion of intra‐vaginal device causes an increase in plasma cortisol concentrations in beef cows, although the pathophysiological significance of the elevation of cortisol is not known.     

Adrenocortical Response in Cows after Intramuscular Injection of Long‐Acting Adrenocorticotropic Hormone (Tetracosactide Acetate Zinc Suspension)

The objectives of this study were first to show adrenocortical response to a long‐acting adrenocorticotropic hormone preparation (tetracosactide acetate zinc suspension) (ACTH‐Z) and its effect on adrenocortical function in beef cows ( Experiment 1 ) and second to apply the ACTH‐Z challenge in dairy cows based on cortisol concentrations in milk collected at routine milking ( Experiment 2 ). In Experiment 1 , four beef cows in luteal phase were challenged with ACTH‐Z, and plasma cortisol concentrations were determined for 48 h after the injection at 30‐min to 2‐h intervals. A rapid ACTH test was conducted 3 days before and 2 h after the completion of ACTH‐Z injection for 48 h to investigate the effect on adrenocortical function. Plasma cortisol concentrations increased significantly 30 min after ACTH‐Z injection (p < 0.001), and the high cortisol levels were maintained for approximately 10 h after the injection. In Experiment 2 , eight dairy cows were subjected to ACTH‐Z challenge 1–2 weeks and 4–5 weeks post‐partum. Blood and milk samples were taken at morning and afternoon milking. All the cows showed a significant increase in cortisol concentrations in plasma as well as in skim milk 8 h after ACTH‐Z injection 1–2 weeks and 4–5 weeks post‐partum (p < 0.001). There was a significant correlation between plasma and skim milk cortisol concentrations 8 h after ACTH‐Z challenge (r = 0.74, p < 0.001). The results obtained in this study suggest that elevated levels of plasma cortisol are maintained for approximately 10 h after ACTH‐Z treatment without adverse effect on adrenocortical function and a long‐acting ACTH‐Z challenge based on cortisol concentrations in milk, which were collected at the morning and the afternoon milking, can be a useful tool to monitor adrenocortical function in cows.     

Response of cattle upon reexposure to Anaplasma marginale after elimination of chronic carrier infections

Sixteen cattle serotest-negative for anaplasmosis with either no previous exposure (2 animals) or cleared 8 months earlier of their carrier state by chemotherapy (14 animals) were each exposed to Anaplasma marginale. Anaplasma serotest titers were determined by complement-fixation and rapid card agglutination tests conducted during a 63-day trial period. Serologic reactions indicated that all cattle (both groups) were converted to seropositive by the 21st day after exposure. Fluctuations in PCV were seen in the 2 groups between days 21 and 35. However, parasitemia levels were detectable only in the 2 previously unexposed control cattle. Three splenectomized calves, given 10 ml of blood from 3 of the former carrier cattle 14 days after the latter were reexposed, developed severe clinical and hematologic signs of anaplasmosis and seroconverted from negative to positive on both serologic tests. The need to acquire a better understanding of immunity in anaplasmosis is discussed.     

Responses of cats to nasal vaccination with a live, modified feline herpesvirus type 1

Intranasal vaccination with a cold-adapted strain of feline herpesvirus type 1 (FHV-1) two days before challenge gave partial protection, and four days before challenge gave complete protection, against feline viral rhinotracheitis. Protection at this time appeared to be specific since vaccination with FHV-1 did not affect the disease caused by the unrelated feline calicivirus. The time course of onset of protection also confirmed that the protective mechanism was likely to be specific. However, six days after vaccination only low levels of FHV-specific IgA and IgM antibody and of interferon were found in serum and nasal washings. In lymphocyte transformation assays neither peripheral blood lymphocytes nor tonsil lymphocytes gave a significant proliferative response in the presence of FHV antigen. Pathogenesis experiments demonstrated that the tonsil and nasal turbinates were the most important sites of virulent FHV-1 replication. Vaccination significantly reduced levels of infectious virus found in both sites. The results provide evidence that no one mechanism is responsible for protection following vaccination but local specific responses are more likely to be involved.     

Evaluation of the morantel sustained release bolus in cows and calves

The efficacy of the morantel sustained release bolus (MSRB) in controlling gastrointestinal parasitism in beef cattle was assessed during the 1982 spring-autumn grazing season. Forty-eight cows and their calves were allotted to three equal groups. One group (T-1) served as a nonmedicated control group. One MSRB was administered to each calf of the T-2 group, and to each cow and calf of the T-3 group at the beginning of the study. The efficacy of the bolus was assessed by comparison of weight gain performance and parasitological data (fecal worm egg counts, herbage larval counts, worm counts from tracer and principal trial calves, and plasma pepsinogen level determinations). Though not statistically significant, treated calves from Group T-2 had a numerical mean weight gain advantage of 2.6 kg, and those from Group T-3 of 4.7 kg, over control calves. Average daily gains (ADG) for the three groups of calves were 0.69, 0.72, and 0.73 kg, respectively. Untreated cows from Group T-2 and treated cows from Group T-3 outperformed the control cows by 12.3 and 7.5 kg, respectively. Fecal worm egg counts from both groups of treated calves were significantly (P less than 0.01) lower than counts from control calves during the entire 169-day trial; notably, egg counts were reduced by 99% 28 days after MSRB administration to both groups of calves. There were no significant differences in the number of eggs counted from the three groups of cows, probably because of the very low numbers of eggs encountered. Mean total worm burdens of principal calves (six per group) necropsied at trial termination indicated a 91% (P less than 0.01) reduction in Group T-2 and an 87% reduction (P less than 0.01) in Group T-3. Worm-free tracer calves were introduced onto pastures every 28 days to monitor availability of infective larvae. The mean number of worms recovered at necropsy from tracer calves that grazed with control cattle increased as the season progressed. However, the numbers of parasites recovered each month from mid-August through mid-October from tracers that grazed pastures with treated cattle were lower (P less than 0.05) than those levels displayed at trial initiation. In addition, the mean numbers of worms from treated group tracers were lower than from the controls for each necropsy period.(ABSTRACT TRUNCATED AT 400 WORDS)     

Influence of diet on postweaning malabsorption and diarrhoea in the pig

Five-day-old pigs challenged with 10(3) pathogenic Escherichia coli (nalidixic acid resistant) showed no clinical signs of disease until subsequently weaned at three weeks. Dietary manipulation was shown to influence xylose malabsorption, diarrhoea and bacterial proliferation after weaning. Brief, but not continuous, contact with the diet before weaning markedly increased the severity of subsequent disease after weaning. Immunogenicity of the weaning diet was critical for the development of the disease. Two diets, identical except that in one the protein source (casein) had previously been enzymatically hydrolysed, were compared. Pigs fed the predigested diet showed no clinical signs of post weaning diarrhoea whereas those fed the untreated casein all developed diarrhoea.     

Transfer of parental immunity to infectious laryngotracheitis in chicks.

The transfer of parental immunity to infectious laryngotracheitis was appraised by measuring serum antibody levels in 150 chicks from the day of hatch up to five weeks. The breeder flock which had received primary vaccination at eight weeks and a booster at 20 weeks transferred high antibody levels which fell markedly within two weeks and remained constant thereafter. Chicks whose parents were vaccinated at 20 weeks only, had low antibody levels throughout. These low levels, in either group of chicks, appeared to offer marginal protection only and were unlikely to inhibit the response to primary vaccination.     

Involvement of PAPP‐A and IGFR1 in Cystic Ovarian Disease in Cattle

Cystic ovarian disease (COD) is one of the main causes of infertility in dairy cattle. It has been shown that intra‐ovarian factors, such as members of the insulin‐like growth factor (IGF) system, may contribute to follicular persistence. The bioavailability of IGF to initiate its response by binding to specific receptors (IGFRs) depends on interactions with related compounds, such as pregnancy‐associated plasma protein A (PAPP‐A). The aim of this study was to determine IGFR1 and PAPP‐A expression both in follicles at different stages of development and in cysts, to evaluate the roles in the etiopathogenesis of COD in cattle. The mRNA expression of PAPP‐A was higher in granulosa cells of large tertiary follicles than in cysts, whereas the protein PAPP‐A present in the follicular fluid from these follicles showed no differences. Although no PAPP‐A mRNA expression was detected in smaller tertiary follicles, in their follicular fluid, this protease was detected in lesser concentration than in cysts. The mRNA expression of IGFR1 was lower in granulosa cells from cystic follicles than in those from tertiary ones. However, the protein expression of this receptor presented the highest levels in cystic structures, probably to increase the possibility of IGF response. The data obtained would indicate that animals with COD have an altered regulation of the IGF system in the ovary, which could be involved in the pathogenesis of this disease in cattle.