Aspects of the health and welfare of continuously housed dairy cattle

Wells, Rhona Jane (1990) Aspects of the health and welfare of continuously housed dairy cattle. MSc(R) thesis, University of Glasgow.

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Abstract

The literature relating to the health and productivity of continuously housed or ''storage fed ''dairy cows with particular reference to the adoption of this type of management system was reviewed. Emphasis was placed on means of improving the output of the dairy herd by storage feeding and also crossbreeding and the relationship between the application of these two techniques and the health and welfare of dairy cattle. Although frowned on in some quarters it was considered that provided production figures were used alongside other findings and interpreted with care they could be useful indications of both health and welfare. Two treatment groups, one containing Jersey cross Friesian cattle (Jx) and the other containing purebred British Friesian's were produced. These two groups were the basis of the study and were continuously housed for five years being allowed to graze naturally only in the last summer of the study. Shortly after birth calves were weighed and blood samples obtained for immunoglobulin analysis by the Zinc Sulphate Turbidity Test (ZST). During calfhood the two breed types showed statistically significant differences for weights (P<0.001) and ZST (P<0.01) results. The Friesian calves had the highest weights but ZST levels were higher for the Jx. Correlations and regressions of weight and ZST were also carried out to determine interparameter relationships. After weaning both groups were housed continuously in a single span cubicle shed and were storage fed on an identical complete diet until eventually they were allowed to graze in the latter part of their third lactation. Intakes of diet were calculated twice weekly with stock weighing weekly and condition scoring fortnightly. No major health problems were noted during this period and weight gains were more than adequate though again the Friesians significantly outperformed the Jersey cross. After first calving and throughout the experimental period milk samples were obtained weekly at both afternoon and morning milkings from each cow and analysed for butterfat, protein and lactose content. There was no evidence of continuous housing reducing the level of output of either breed type and fat and protein percentage indicated that nutritionally the system had advantages over a traditional grazing regime . Statistical analysis of weights, yield and milk constituents was undertaken and while yields were found not to be significantly different butterfat and protein percentage were significantly higher in the Jx (P<0.001) and weights lower. Fertility was good throughout the housing period the Jx generally outperforming the Friesians. Indeed the fertility figures and maintenance of fat and protein levels throughout the three lactations indicated advantages in the use of this type of regime. During an intensive monitoring period over the major part of the third lactation milk samples were also obtained for estimation of somatic cell numbers and chloride concentration at both afternoon and morning milkings on a monthly basis. In addition at the morning milking a cowside California Mastitis Test (CMT) was performed on each cow by quarter (paddle test) to assess subclinical mastitis incidence. Milk samples were obtained from each quarter giving a positive CMT reaction for bacteriological analysis, somatic cell counts and chloride concentration and when two or more quarters gave a positive CMT result all quarters were sampled. The extent of subclinical mastitis was higher than expected given the background somatic cell (SCC) and total bacterial cell count (TBC) figures for the entire herd the rest of which was allowed to graze in summer. Statistical analysis of these positive CMT milk results was undertaken using an analysis of deviation technique, chloride being found to be significant for group and somatic cell counts for month (P<0.05). Regression and correlation analyses were also carried out and it was found that the most significant parameters were chloride and lactose concentration which were respectively lower and higher in the Jx.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Additional Information: Adviser: D N Logue
Keywords: Animal sciences
Date of Award: 1990
Depositing User: Enlighten Team
Unique ID: glathesis:1990-72078
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 17 May 2019 13:06
Last Modified: 17 May 2019 13:06
URI: http://theses.gla.ac.uk/id/eprint/72078

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