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Biomedical subjects

T K Griffin

Publications and source records attributed to T K Griffin.

12 recordsLinked to original sources
PubMed1989

Effect of hydraulic milking on milking performance, teat condition and lipolysis.

The term 'hydraulic milking' describes a new milking concept in which liner movement is restricted and the liner is flooded with milk beneath the teat. This condition, achieved with a multi-valve claw without air admission to the cluster, reduced milking time by 26% and increased milk flow rate by 20%. Four experiments describe the discovery of hydraulic milking and investigate its potential using equal or different levels of vacuum in the milkline and pulseline. Benefits from hydraulic milking include decreased lipolysis (less than or equal to 36%) and milk foam (75%), improved teat condition and a high degree of protection against machine-induced infections. Evidence of increased milk yield is inconclusive. Cluster removal is impeded by hydraulic milking and the multi-valve cluster requires modification to facilitate the process. Pulsation characteristics and vacuum levels developed for conventional milking appear adequate for hydraulic milking. Unorthodox vacuum conditions may be needed, however, to exploit fully this novel milking concept.

Animals↗
PubMed1988

A multi-valved milking machine cluster to control intramammary infection in dairy cows.

A milking machine claw incorporating valves to prevent movement of milk between teats during milking, and its contribution to the prevention of udder infection under experimental and field conditions, is described. Under experimental conditions a suspension of Streptococcus agalactiae and Str. dysgalactiae was introduced into the milking cluster during milking; 11 of 40 quarters became infected using a conventional claw piece whereas none of 40 quarters milked with the multi-valve claw developed intramammary infection. In a 12-month experiment in ten commercial herds, each split into two equal susceptibility groups, the multi-valved cluster reduced the incidence of new infection with coliforms and Str. uberis by 17% (P less than 0.1). The incidence of all new infections and new clinical cases was 14 and 25% lower compared to conventional clusters but these reductions were not significant.

Animals↗
PubMed1984

Observations on Corynebacterium bovis infection of the bovine mammary gland. I. Natural infection.

Data from experiments in 55 commercial herds have been examined to study the patterns of Corynebacterium bovis infection. Such infections are most common in herds that are not subjected to regular control methods but their commercial significance appears to be small. In herds using teat disinfection and dry cow therapy levels of infection with this organism are low. There is no evidence from these data to suggest that C. bovis infections protect the udder against invasion by a major pathogen. On the contrary these infections do not persist when major pathogens invade.

Animals↗
PubMed1983

Use of deflector shields to reduce intramammary infection by preventing impacts on the teat ends of cows during machine milking.

A series of short duration experiments has shown that infections caused by the milking machine or the way in which it is used can be controlled by fitting deflector shields in the teatcup liners. This not only provides a simple means of controlling such infections, but demonstrates that they result from penetration of the streak canal of the teat by contaminated milk particles impacting on the teat ends.

Animals↗
PubMed1980

Effect of deflector shields fitted in the milking machine teatcup liner on bovine udder disease.

Deflector shields were inserted in the teatcup to prevent 'impacts' against the teat end, and their effect on the rate of new udder infections was studied on 15 commercial dairy farms in Britain and 16 in Australia. Small metal shields were fitted between the liner barrel and short milk tube of 2 teatcups in each cluster in a milking installation so that all cows in a herd always had the same 2 quarters shielded. Half-udder comparisons were made using 1039 cows in the British herds and 1268 in the Australian herds. Herds were quarter-sampled for cytological and bacteriological examination when shields were fitted at the start of the experiment and again after 6 months. The shield effects were similar in the 2 experiments. The combined results from the 31 farms showed that 10.5% fewer quarters became infected when protected by shields (P less than 0.05). In the 1287 cows that had no infected quarters at the start of the trial, 15% fewer quarters became infected when protected by shields (P less than 0.01). The shield effect was mainly confined to hind quarters in which 23% fewer shielded quarters became infected (P less than 0.001). The small reduction of 2% in forequarters was not significant. In the 16 herds in which post-milking disinfection of teats was practised, shielded quarters had 23.5% fewer new infections than unshielded quarters (P less than 0.01). In 6 British herds milked in installations classed as non-standard, shielded quarters had almost 50% fewer new infections than the unshielded quarters (0.05 less than P less than 0.10). The results provide evidence of a milking machine effect, at varying levels of intensity, to increase new infection rates on all or most farms. Control of this machine effect could lead to substantial reduction in new infections in some herds and a modest reduction in most.

Animals↗
PubMed1977

A method of diagnosing intramammary infection in dairy cows for large experiments.

Diagnosis of microbial infections in the udders of cows in commercial dairy farms for large experiments cannot be without error. Limitations of sampling method and routine prevent collection of the necessary information for sure diagnosis. However, with an organized method of repeated bacteriological examinations using consistent and proven methods of aseptic sampling the errors were shown to be very low. A method based on bacteriological tests on aseptic milk samples was used in 32 herds (approximately 2000 cows) for a 3-year period. This is described and examined in terms of other criteria to validate its use in experimental work. With this method it was not difficult to differentiate between those quarters which regularly shed pathogens and those which did not. Other evidence indicated that it was reasonable to assume that this classification accurately distinguished between infected and uninfected quarters. The errors using this method were quite small: when measuring the state of infection of all quarters in the herds the errors did not exceed 1%. Some small modifications to the method described are suggested to improve further its diagnostic accuracy.

Animals↗