Propionate loading test for liver function in spontaneously ketotic dairy cows

Propionate utilisation by the liver in spontaneously ketotic dairy cows was investigated by determining blood glucose levels after an intravenous sodium propionate load (2.5 mmol kg-1). In addition, blood ketone body concentrations were measured after propionate loading. Cows were divided into three groups (control, mildly ketotic and severely ketotic) by their blood acetoacetate concentrations. Plasma glucose concentrations increased significantly after sodium propionate injection in all three groups (P less than 0.05). The maximum glucose concentration occurred earlier in the control group than in the ketotic groups. Changes in glucose concentrations following propionate loading of control and ketotic cows differed significantly at 20 minutes and beyond. Differences in the change in glucose concentration between mildly ketotic and severely ketotic cows were not significant. Acetoacetate concentration was significantly decreased at five minutes and beyond after the injection in ketotic cows, whereas beta-hydroxybutyrate concentration decreased more slowly. A decrease in beta-hydroxybutyrate concentration was significant at 40 minutes and beyond in the severely ketotic group and at 10 minutes and beyond in the mildly ketotic group after loading.     

Antiserum against culture filtrate is cross-protective for various serovars of Erysipelothrix rhusiopathiae

The protective effect of porcine antiserum prepared against culture filtrate (CF) of an attenuated strain of Erysipelothrix rhusiopathiae (serovar 2) in mice to challenge with 20 virulent strains of 18 serovars and one type N was investigated. Passively immunized mice survived after challenge with serovars 1a, 1b, 2, 5, 6, 8 (strain Goda), 11, 12, 15, 16, 21 or type N, but 10-30% mortality occurred in immunized mice challenged with each strain of serovars 4, 7, 8 (strain 911), 9, 18 or 19 and 70% mortality to serovar 10 (strain 2179). All immunized mice died after challenge with serovar 20 (strain 2553). Non-treated control mice died after challenge with all serovars and the type tested.     

Estimation of the costs of mastitis, using National Animal Health Monitoring System and milk somatic cell count data

Data collected by the National Animal Health Monitoring System in Ohio for a 12-month period during 1986 and 1987 were used to determine the relative magnitude of costs associated with mastitis in the following categories: milk production loss, veterinary services, drugs, producer labor, and "other" factors. The cost of milk loss associated with mastitis that was reported by producers cooperating in the National Animal Health Monitoring System program was compared with estimates based on bulk tank somatic cell counts and individual cow milk somatic cell counts. Using producer-reported estimates, milk loss accounted for about one third of the total cost associated with mastitis. When estimates of milk loss were replaced by estimates based on bulk tank somatic cell counts, milk loss accounted for over 80% of the total cost of mastitis. Estimates of the cost of milk loss based on studies relating milk yield to somatic cell counts differed considerably. Consequently, it was unclear how to best estimate the relative magnitude of the milk loss component of mastitis costs.     

Some factors affecting urinary and Faecal nitrogen loss by chickens fed on a protein‐free diet

1. In adult colostomised cockerels, the rates of urinary and faecal nitrogen loss were measured when feeding low‐ and high‐energy, protein‐free diets after a preliminary period during which diets of differing energy and protein contents had been fed.

2. Urinary nitrogen excretion increased with increasing protein and decreasing energy in the preliminary diet.

3. Urinary nitrogen excretion was high during the first 3 d of feeding a high‐energy, protein‐free diet, decreased rapidly during the next 3 d and thereafter become relatively constant. However, in the case of a low‐energy, protein‐free diet, urinary nitrogen excretion gradually declined throughout the trial period of 15 d, resulting in increased urinary nitrogen excretion.

4. After a 3‐d period of adjustment faecal nitrogen loss from birds fed on a protein‐free diet was relatively constant under the conditions examined.     

Prokinetic effects of cisapride, naloxone and parasympathetic stimulation at the equine ileo-caeco-colonic junction

The electromyogram of the terminal ileum, the caecum and the proximal right ventral colon was recorded in fasted conscious ponies receiving intravenously equiactive doses of pilocarpine (0.05 mg/kg) and carbachol (0.01 mg/kg) as acetylcholine analogues; cisapride (0.1 mg/kg) and metoclopramide (2 mg/kg) facilitating acetylcholine release from myenteric neurones and naloxone (0.05 mg/kg) as an antagonist of the endogenous inhibitory opioid system. Both cisapride and naloxone induced typical migrating spike bursts in the colon associated with contractions of caecal body and caecal base. Both pilocarpine and carbachol stimulated the terminal ileum but had opposite effects on the activity of the caeco-colonic segment which was decreased by pilocarpine and increased by carbachol. High doses of metoclopramide had weak and unspecific stimulatory motor effects. It is concluded that a true prokinetic effect at the equine ileo-caeco-colonic junction requires a motor profile which includes coordination between contractions sequentially involving the body and the base of the caecum and migrating spike bursts on the proximal colon. Such changes in the motor profile were produced by cisapride and naloxone and to a lesser extent by carbachol.