Severe Clinical Mastitis Research Articles

Vaccination of cows with rough Escherichia coli mutants fails to protect against experimental intramammary bacterial challenge

Vaccination of cows with rough Escherichia coli mutants fails to protect against experimental intramammary bacterial challenge. Vaccine A, a heat-killed Re mutant of strain K12, (UB 1574), was administered as a single parenteral and local dose to 5 cows with 3 control animals and Vaccine B, a heat-killed mutant of O111:B4 (J5) was administered as three parenteral doses into 5 cows with 5 control animals. Following intramammary challenge with a smooth wild-type strain (P4), an acute, severe clinical mastitis developed in all 14 quarters (9 vaccine A and 5 vaccine B) of the vaccinated animals which was indistinguishable from that in the 11 quarters of the control animals. Following vaccine B there was an elevation in serum IgG1 and IgG2 antibody to the common core antigen of endotoxin which, in contrast to the control animals, showed a further increase after intramammary infection.

Value of re-treating the dry cow

Since the anti-mastitic effects of mammary gland infusion carried out at drying off last for approx. 20 days, whereas dry period tends to be approx. 60 days, a study was carried out to assess the economic and prophylactic value of re-treatment of cows during the dry period. Udders of Holstein cows that had been selected alternately from a herd of 420 were infused with Cephalosporin (200 mg/quarter) 2-3 wk prior to parturition. Incidence of mastitis at and after parturition was then assessed, and costs of re-treatment were compared with costs for treatment of mastitis outbreaks. For simple mastitis, cost of prophylactic retreatment was considerably higher than cost of treating one episode of mastitis; costs for treatment of severe mastitis were, however, approx. equivalent to costs of re-treatment. Routine prophylactic re-treatment is not therefore recommended for cows prepartum unless there is a high incidence of severe clinical mastitis post partum.

Teat burns in dairy cattle--the prognosis and effect of treatment.

Twenty cows and 20 uncalved 20 month old heifers with severely burnt teats were studied. Ten of each group received topical treatment with a mixture of lanoline, cetrimide and dimethyl sulphoxide or vitamin A and petroleum jelly, respectively. Prognosis for survival and future normal milking ability was poor in heifers (8 subsequently normal of 20 assessed) but moderate in cows (9 cows with normal and 5 cows with partial machine milking ability of 18 cows fully assessed). Treatment did not significantly increase the rate of epithelialisation of wounds. Topical treatment had no effect on the prognosis of heifers. However treated cows were more likely than control cows to survive and to show adequate teat function following subsequent calving. Severe clinical mastitis prior to calving, teat distortion and teat canal constriction were common sequelae. Recommendations on the management of heifers and cows with severely burnt teats are made.

Prognosis for cows with severe clinical coliform mastitis.

A retrospective study was performed at the New York State college of veterinary medicine, ambulatory clinic to determine the prognosis for cows with peracute or acute coliform mastitis. Eighty-eight cows were identified by their clinical signs and positive culture of coliform organisms. In 59.1 per cent of the affected cows the quarters returned to a milk-like secretion approximately one month following treatment. The 59.1 per cent was composed of 37.5 per cent (of the initial 88 cows), which milked in the affected gland the following lactation, 11.4 per cent which were culled, and 10.2 per cent which had not yet calved and begun their next lactation. The remainder of the affected cows failed to return to milk in the affected quarter that lactation. This percentage consisted of 17.0 per cent which were culled for hypogalactia, 6.8 per cent which died during the attack, 4.6 per cent in which the affected quarters were rendered inactive with an irritant, 1.1 per cent in which the outcome was undetermined since they had not begun their next lactation and 11.4 per cent which remained in the herd. Of the 11.4 per cent, half produced milk in the affected quarter the following lactation, and half failed to return to milk.

Streptococcus uberis of Bovine Mastitis Origin: Isolation, Characterization, and Serology of Two Mucoid Strains

Thirty-three per cent of the quarters in a private herd of 30 Holstein cows that had severe clinical mastitis produced visibly abnormal milk at one milking. Milk samples from this herd taken 14 months apart yielded two mucoid strains, U3M and U5M, biochemically typical of Streptococcus uberis. Of 8 samples taken from glands infected solely with Streptococcus uberis, seven had standard plate counts of at least 390,000 per milliliter. Significant differences were noticed between the 2 mucoid strains. U3M did not ferment melezitose, was CAMP positive in TKT medium, grew in 4% NaCl, and grew at temperatures of 21 and 45C, but U5M possessed opposite characteristics. Two nonmucoid strains were selected from the mucoid strains by passage in laboratory media. There were no differences in biochemical and physiological characteristics between the mucoid strains and their own nonmucoid variants. Cross-agglutination tests with hyperimmune sera indicated a definite relationship among the two mucoid strains and their nonmucoid variants. However, a high titer was noted only for the homologous antiserum of the U5M strain. Autoagglutination was an important problem. Presence of group specific precipitating antibody could not be demonstrated by the capillary tube precipitin or gel-diffusion tests. The three strains tested failed to react with any of the Lancefield group sera. Three strains of S. uberis in pathogenicity trials were avirulent for laboratory mice.