A survey of the phosphorus and calcium contents of pastures and the serum inorganic phosphorus and calcium contents of cows on four Manawatu dairy farms

Serum inorganic phosphorus (Pi) and calcium (Ca) concentrations were assessed in 20 cows on each of four Manawatu factory supply dairy farms. Blood was taken from each cow before calving and at six-week intervals during lactation. Bleeding coincided with herd testing. Herds of Friesian or Friesian X cows and Jersey or Jersey X cows were compared on adjacent farms on a Central Yellow-brown Sand and on adjacent farms on a Peat Loam overlying a Central Yellow-brown Earth soil. Pasture mass and composition were estimated to grazing height in the next two paddocks to be grazed in the rotation. Mean serum Pi concentration was higher in cows on sandy soils (1.55 mmol Pi/l than in cows on the peat loam (1.34 mmol Pi/l (P<0.001). Concentrations were highest before calving (1.69 mmol Pi/l) but fell to low levels at peak lactation (1.17mmol Pi/l when 70% of cows were below the minima of the 'normal range', and during the drought (1.29 mmol Pi/l. Pasture phosphorus (P) concentrations were adequate to support cow nutrition for lactation (>0.33% DM, ad lib. feeding) until the summer drought when low herbage mass would have restricted milk production. Serum Ca was adequate for lactating cows and changed little between months or between cows (mean 2.12 mmol Ca/l). No metabolic disorders relating to mineral deficiencies were observed. It appears that serum Pi in a high proportion of cows falls below the normal range during peak lactation without cows displaying clinical deficiency symptoms or a depression in butterfat production.     

Electrocardiograms as an aid in assessing the stunning of cattle and pigs

Electrocardiograms (ECG's) were made from cattle and pigs after slaughter using only the left arm and right arm recording electrodes of a portable electrocardiogram with 12 recording electrodes. Functional heart activity was demonstrated in cattle after stunning with a captive bolt, nonpenetrative percussive methods and a head-only electrical technique. Recordings compatible with ventricular fibrillation were made in the majority of cattle and pigs subjected to a head-to-chest form of electrical stunning. In cases where the placement of stunning electrodes was defective, functional cardiac activity could be detected. Movement artefact on the ECG trace associated with epileptiform seizures following head-only electrical stunning was a technical problem. This was reduced by restunning the animal with a captive bolt before taking an ECG. The examination of ECG's made subsequent to slaughter could form an important component of the quality control of Halal slaughter or a slaughter process using the head-to-body electrical stunning techniques. Adoption of this would be facilitated by the development of a more simple and less sensitive electrocardiograph than that used in the present investigation.     

The veterinarian and animal welfare

At no important point does the Animals Protection Statute mention the competence of Veterinarians, but the "competent Authority". Also, the Animal Epidemics Statute and the Federal Hunting Statute provide for the cooperation of the veterinarian, but not for his competence to make decisions. This situation is even being overlooked by the investigating authorities, when in the case of using animals for "sport" or other problematic events, questions of the animals psychology and ethology have to be dealt with. In the courts the remarks of non-specialist qualified persons can lead to wrong decisions as can either unsuitable or wrong evidence.     

An osteodystrophy apparently caused by vitamin D deficiency in growing pigs

An osteodystrophy with features of both rickets and fibrous osteodystrophy was diagnosed in growing pigs housed indoors and fed on a diet deficient in vitamin D. Affected pigs were severely lame and preferred to remain recumbent. At necropsy, the long bones had reduced breaking strength and in one five-month-old pig the articular surfaces of both proximal humeri were indented due to collapse of subchondral bone. Microscopic changes in the bones included prominent osteoclastic activity in the proximal metaphyses, variable myelofibrosis, trabecular microfractures, and focal thickening of the hypertrophic zone in some growth plates. Treatment consisted of an injection of Vitamin D3, addition of dicalcium phosphate to the diet for 18 days and long-term supplementation of the diet with fat-soluble vitamins. This is the first report of an osteodystrophic disease in pigs in New Zealand.