Continuous sampling of the same cattle was carried out on several groups of animals, at regular intervals of 3 or 5 weeks, for periods up to 22 months. Normal range of values were obtained for serum Ca, serum Mg, inorganic P, blood sugar, chlorine and. N. P.N. No change in blood composition could be attributed to lactation or to season of the year: slight seasonal differences were associated with grazing. Parturition caused decrease in serum Ca and inorganic P: the fall in inorganic P was more marked, and was even diagnostic of approaching labour. The hypocalcaemia at parturition is discussed in relation to milk fever, the hypocalcaemia of which appears to be a pathological exaggeration of a normal physiological phenomenon. Calves at birth have higher levels of serum Ca, inorganic P, blood sugar and N. P.N. and lower levels of serum Mg and chlorine than are normal in the dam. In general the blood of the calf attains the dam's normal at the age of about 6 months. Increase in P intake caused a rise in inorganic P level: when Ca intake was lowered at the same time as P intake was raised the rise in inorganic P was greater but serum Oa showed little or no alteration. 7. A diet rich in clover, when associated with shortage of water, caused over 100 % rise in N.P.N. 8. Evidence is provided of a definite diurnal rhythm in the blood sugar level of lactating cows, apparently associated with withdrawal and secretion of milk, since it did not appear in dry cattle or sheep.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:591113 |
| Date | January 1934 |
| Creators | Allcroft, William Miller Ord |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU465915 |
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