[Milk cell count as a selection criterion in breeding dairy cattle with improved resistance to mastitis].

The cell counts in the milk of female progeny of thirty-one bulls of the Meuse-Rhine-IJssel breed were determined in three breeding areas in the Netherlands, viz., in the provinces of Overijssel, Gelderland and North Brabant. The individual cell counts of the milk of 1,741 females in their first lactations were determined in study I.

Effect of bull selection for somatic cell count in first lactation on cell counts and pathogens in later lactations.

Somatic cell counts were measured one time on Meuse-Rhine-Ijssel cattle in The Netherlands. Experiment 1 involved 1,741 first lactation daughters of 31 bulls. Eleven bulls with daughters with either high or low average cell count were selected for further study of their daughters in third and fourth lactation.

[Effect of intramammary vaccination on experimental staphylococcal infection (author's transl)].

A commercial vaccine for intramammary inoculation to prevent staphylococcal mastitis was tested under experimental conditions. Groups of cows which were vaccinated in all four quarters, in two quarters in the dry period and which were not vaccinated respectively were challenged intramammary with a mixture of alpha, beta, alpha + beta, haemolytic strains of Staphylococcus aureus during lactation. After challenge, severe mastitis developed in most cows.

[Mycoplasma bovis mastitis in a dairy herd in the Netherlands (author's transl)].

The first observation of an outbreak of mastitis, caused by Mycoplasma bovis, in a dairy herd in the Netherlands is reported. The symptoms closely resembled those reported in the literature as being typical of mastitis due to Mycoplasma. The strain isolated was found to be sensitive to amongst others nifuroquine in vitro.

[Genetic features of mastitis (author's transl)].

Every disease is due to genetic and environmental factors; this also is true of mastitis. Differences in susceptibility to mastitis between two groups of paternal half-sibs and between two breeds are based on genetic differences. Groups of cows which were less susceptible to mastitis showed lower milk cell counts as early as the first lactation.

Milk cell count in machine milked dairy goats.

Milk samples from 3 machine milked herds with 185 goats were examined for mastitis. Bacteriologically positive results were very few but the cell counts were high. These findings are in contrast to the results obtained with cows' milk samples.

Milk cell count in machine milked dairy goats.

Summary Milk samples from 3 machine milked herds with 185 goats were examined for mastitis. Bacteriologically positive results were very few but the cell counts were high. These findings are in contrast to the results obtained with cows' milk samples.

An investigation of the pathology of mycoplasma mastitis in the cow.

A field case of mastitis in cows, caused by Mycoplasma agalactiae var. bovis, formed the occasion to conduct an infection experiment. Five lactating heifers were infected in the udder at different times.

An investigation of the pathology of Mycoplasma mastitis in the cow.

Summary A field case of mastitis in cows, caused by Mycoplasma agalactiae var. bovis, formed the occasion to conduct an infection experiment. Five lactating heifers were infected in the udder at different times.

Differences in mastitis susceptibility between Holstein Friesian, Dutch Friesian and Dutch Red and White cows. Correlation between parameters for mastitis and for production.

On an experimental farm 3 dairy breeds were compared with regard to mastitis by various parameters. Higher cell counts and more udder infections were present in the Dutch Red and White (DRW) in comparison with the Holstein Friesian (HF) and the Dutch Friesian (DF). Within the HF breed a negative correlation between cell count and production was established and also in this breed, a negative correlation between maximum rate of milk flow and cell count.

Differences in mastitis susceptibility between Holstein Friesian, Dutch Friesian and Dutch Red and White cows.

Summary On an experimental farm 3 dairy breeds were compared with regard to mastitis by various parameters. Higher cell counts and more udder infections were present in the Dutch Red and White (DRW) in comparison with the Holstein Friesian (HF) and the Dutch Friesian (DF). Within the HF breed a negative correlation between cell count and production was established and also in this breed, a negative correlation between maximum rate of milk flow and cell count.

[Difference in susceptibility to mastitis between the Dutch-Friesian and Meuse-Rhine-Yssel breeds of cattle (author's transl)].

A randomized study in the Netherlands showed that symptoms of mastitis were more common in animals of the Meuse-Rhine-Yssel breed than they were in those of the Dutch-Friesian breed. The samples were taken at random from large groups of animals (approximately 10,000) of the dairy cattle population in the Netherlands, quarter samples being examined for the presence of the causative organisms of mastitis and cell counts being made. Differences between the two breeds were also observed in herds on the experimental farm "'t Gen" on which the animals were reared and kept in the same environment.

[Studies on mastitis in ten groups of female offspring (author's transl)].

The incidence of mastitis in groups of female offspring of ten AI bulls was studied under field conditions. Marked variations in the incidence of symptoms of mastitis were observed. The results of this preliminary study were verified experimentally.

The difference in hereditary susceptibility to three mastitis agents between two daughter groups.

Daughter groups of two sires A and Z were kept under equal conditions during 3 lactations. Experimental infections with mastitis agents gave different responses in both groups. The evident difference in susceptibility to mastitis between the A- and Z-daughters is based upon genetic differences.

Mastitis; a survey on the inter-dependence of the quarters of a cow.

This survey shows the dependence of the diagnosis "non-specific mastitis" on the method and interpretation of laboratory examination. Failures in bacteriological diagnosis will often lead to quarters being incorrectly diagnosed as being affected by "non-specific mastitis". The main aim of this survey was to study the interdependence of the quarters of cows with regard to laboratory results on mastitis.