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Biomedical subjects

B F Sansom

Publications and source records attributed to B F Sansom.

At least 37 records · Page 2Linked to original sources
PubMed1982

Calcium mobilisation in hypomagnesaemic cattle.

Intravenous infusions of EDTA solution (4.7 per cent w/v) were used to induce hypocalcaemia in six steers and six non-pregnant lactating Friesian cows, once when they were normomagnesaemic and once when they were hypomagnesaemic (less than 0.85 mmol Mg per litre) and their rates of calcium mobilisation have been measured. The mean rates of calcium mobilisation by the normo- and hypomagnesaemic steers were 0.32 mmol/min and 0.21 mmol/min respectively (P less than 0.005) and the mean calcium mobilisation rates of the cows were 0.41 mmol/min and 0.26 mmol/min respectively (P less than 0.02). It is concluded that hypomagnesaemia reduced the calcium mobilisation rate in both steers and non-pregnant lactating cows.

Animals↗
PubMed1981

Study of combined injections of 1 alpha-hydroxy-cholecaldiferol and cloprostenol in the prevention of parturient paresis.

Dairy cows were injected with 1 alpha-hydroxycholecalciferol (1 alpha-HCC) and, or, cloprostenol at 275 days of gestation. Blood samples were taken daily from 270 days of gestation until seven days after parturition and analysed for calcium, inorganic phosphate, magnesium and hydroxyproline. In all treated and control cows concentrations of calcium, inorganic phosphate and magnesium decreased around the time of parturition. Concentrations of hydroxyproline increased from the second to the fourth day after parturition. This increase was slightly smaller in cows injected with cloprostenol but was unaffected by 1 alpha-HCC. There was a greater indicence of retained placenta and endometritis in cows receiving cloprostenol. The injection of cloprostenol with 1 alpha-HCC at 275 days of gestation did not prevent milk fever.

Animals↗
PubMed1981

Field trial to determine the efficacy of two doses of 1 alpha-hydroxycholecalciferol in the prevention of milk fever.

The efficacy of 1 alpha-hydroxycholecalciferol (1 alpha-HCC) for the prevention of milk fever has been tested in a controlled field trial using a total of 601 cows on 18 farms with a history of a high incidence of milk fever. The trial protocol proposed two doses of 1 alpha-HCC with the first injection seven days before the predicted calving date and a second injection five to seven days later if the cow had not calved. Of 301 cows receiving either one or two injections of 1 alpha-HCC, 70 had milk fever, and of 300 cows that received a placebo, 102 had milk fever. The difference in incidence between the two groups was statistically significant (P = 0.005) and indicated an overall efficacy of 32 per cent for treatment with 1 alpha-HCC. An improved efficacy was demonstrated in 67 cows that received two injections of 1 alpha-HCC with the second injection administered either on the day of calving or one day previously (60 per cent efficacy). For 42 cows that received a single injection of 1 alpha-HCC between two and five days before calving an efficacy of 79 per cent was achieved.

Animals↗
PubMed1981

The ingestion of sow's faeces by suckling piglets.

1. Six sows were housed in solid-floored farrowing pens and fed daily with approximately 200 microCi 198 Au, three of them from 3 d before farrowing until their piglets were 10 d old and three fr om 10 d after farrowing until their piglets were weaned at 21 d. 2. The sows' faeces and sawdust bedding became radioactive but their milk remained free of radioactivity. The piglets' radioactivity was measured daily in a whole-body counter after they had been washed to remove external contamination. 3. The piglets' mean whole-body radioactivity was equivalent to 20.9 +/- 2.5 g (range 5.7-85 g) of faeces and bedding. If the average passage time of the digesta through the gastrointestinal tract is assumed to be 24 h these values are equal to the average daily intake of faeces and bedding by the piglets. 4. This intake of faeces could possibly prevent the piglets becoming anaemic if the sow's diet were supplemented with iron to increase the Fe concentration of her faeces to approximately 2 mg Fe/g fresh faeces.

Animals↗
PubMed1981

Selenium metabolism in the dairy cow: the influence of the liver and the effect of the form of Se salt.

1. Six adult Friesian cows were given 75Se as either 75SeO32- or 75SeO42- intravenously. Five of the cows had cannulas in an hepatic vein, the portal vein and one carotid artery to enable the uptake of 75Se by the liver to be measured. Radioactive balance studies were carried out on two of the cows given 75SeO32- and two given 75SeO42-. A seventh cow was given an oral dose of 75Se-labelled barley and the excretion of 75Se in faeces, urine and milk was measured for 14 d. 2. After the injection of 75SeO32- plasma 75Se concentration decreased during the first 30 min with a mean half-life (t 1/2) of 15.6 min. From 30 to 60 min after dosing the concentration of radioactivity increased to reach approximately 50% of the level present 2 min after dosing. Following the injection of 75SeO42- the 75Se was cleared with a mean t 1/2 of 28.5 min during the first 30 min and plasma radioactivity increased only slightly during the next 30 min. 3. during the phase of rapid clearance of 75Se after the injection of 75SeO32- the hepatic venous 75Se concentration was approximately 5% lower than portal venous 75Se concentration. During the period when plasma 75Se activity was increasing the activity in hepatic venous plasma was 3% greater than portal activity. Of the 75Se cleared from plasma after injecting 75SeO32- 40% was calculated to be removed by the liver. 4. After intravenous dosing with 75SeO32- or 75SeO42- approximately 9.5 and 17.0% respectively of the dose injected was excreted in faeces and 10% in urine within 14 d. Almost three times as much 75Se was excreted in urine and 3.5 times as much in faeces during the first 24 h after dosing with 75SeO42- as after 75SeO32-.

Animals↗
PubMed1980

The effects of reducing manger space on dairy cow behaviour and production.

The manger space for a group of 30 cows was reduced from 105 cm to 15 cm per cow during a period of six weeks. Before each reduction in manger space the cows were observed for 24 hours and their activity and aggressive behaviour recorded. The activity of individual cows varied little but there was wide variation among cows. The reduction in manger space did not change the mean number of visits by cows to the manger, the total time spent feeding, the amount of aggressive behaviour, the milk yield or the general activity of the cows in comparison with a control group allowed 105 cm of manger space per cow for the whole period. There was a reduction in the total time spent feeding by cows which were clinically ill and a change in the number of visits made to the manger by cows in oestrus. A reduction in the allocation of manger space would make it possible either to build smaller, cheaper housing or to convert existing buildings to accommodate more cows. It would also make it possible to use automated systems to record the feed intake and number of visits to the manger of individual cows and would help to detect cows which were sick or in oestrus.

Aggression↗
PubMed1980

Effect of reduced water intake by lactating dairy cows on behaviour, milk yield and blood composition.

A herd of lactating British Friesian cows was divided into two equal groups. After 14 days during which all the cows had free access to water one group (restricted) was allowed only 50 per cent of the voluntary water intake of the other group (control). After four days when the experiment was terminated, the milk yield of the restricted group had fallen to 74 per cent of that of the control group and their mean body-weight was reduced by 14 per cent. In the restricted group there were significant increases in the concentrations of urea, sodium, total protein and copper in serum, in the osmolality of serum, in the plasma activities of the enzymes creatine kinase and glutamate-oxaloacetate transaminase and in the packed cell volume of blood. The restricted cows behaved very aggressively around their water trough and spent more time in its vicinity. They spent less time lying down than the cows of the control group and some of them were not seen to drink and were withdrawn from the experiment before the end of four days. In a second experiment half the herd was allowed approximately 90 per cent of the water intake of the control group for 14 days. Decreases in milk yield and body-weight and changes in blood composition were much smaller and difficult to detect. However, changes in behaviour were still easily recognised although not as marked as in the first experiment.

Aggression↗
PubMed1979

The half-life of glutamate dehydrogenase in plasma of dry and lactating dairy cows.

The clearance of glutamate dehydrogenase from plasma was measured weekly for three weeks in three dry and three lactating cows. The clearance was exponential with a mean clearance constant of 0.0488/j and means (+/- SE) half-life of 14.2 (+/- 0.77) h. There were variations among cows and among measurements in the same cow but there was no difference between the mean half-lives of GDH in lactating and dry cows. Because of the long half-life the small variations among individual cows are unlikely to affect the interpretation of increased plasma GDH activity.

Animals↗
PubMed1978

A field trial of 1alpha-hydroxycholecalciferol (1alpha-OH D3) in the prevention of milk fever.

The efficacy of 1alpha-OH cholecalciferol for the prevention of milk fever has been tested in a controlled field trial using 597 cows on 19 farms all of which had previously had a high incidence of milk fever. Of 293 cows receiving 1alpha-OH cholecalciferol 34 had milk fever and of 304 control cows 51 had milk fever. Although there was an apparent efficacy of 31 per cent the difference in incidence was not statistically significant. There was no effect if 1alpha-OH cholecalciferol was administered less than 24 hours before the cows succumbed to milk fever. However, if 1alpha-OH cholecalciferol was administered more than 24 hours and less than one week before the occurrence of milk fever the efficacy increased to 61 per cent and the effect was highly significant.

Animals↗
PubMed1978

The absorption of dietary manganese by dairy cows.

Additional manganese, sufficient to increase the dietary concentration to approximately 1000 mg/kg, was administered to one cow for four and another for seven days. Manganese concentrations in portal and mesenteric plasma were increased by a mean of 3.9 microgram/litre above the concentration in systemic plasma. This increment is equivalent to the absorption of 0.54 per cent of the administered manganese. The cow which received manganese for seven days showed after six days larger increases in systemic plasma manganese concentration which may indicate a toxic effect of excess manganese upon the liver.

Absorption↗
PubMed1976

Use of 1alpha-OH cholecalciferol in preventing post parturient hypocalcaemia and its potential value for the prevention of milk fever in dairy cows.

Cows which received 250 mug 1alpha-hydroxy cholecalciferol (1alpha-OH D3) intramuscularly within two hours after calving suffered significantly less post-parturinet hypocalcaemia and hypophosphataemia than control cows. There was a small depression in plasma magnesium concentrations in the treated cows. 1alpha-OH D3 shows potential for the prevention or treatment of milk fever.

Animals↗