The analysis of the milk somatic cell count reducing possibilities.
The somatic cell count (SCC) is commonly used as a measure of milk quality as well as udder health. Somatic cells are simply animal body cells present at low levels in normal milk. High levels of these cells in milk indicate abnormal, reduced-quality milk that is caused by an intramammary bacterial infection (mastitis). The majority of the cells in a somatic cell count are leukocytes (white blood cells), and some are cells from the udder secretory tissue (epithelial cells). The epithelial cells are part of the normal body function and are shed and renewed in normal body processes. The white blood cells serve as a defence mechanism to fight disease (infection), and assist in repairing damaged tissue. Somatic cell counts are based on the number of cells per milliliter (ml, about 10 drops) of milk.
High somatic cell count in milk is abnormal and undesireble. Elevated SCC levels may result from several factors or a combination of these factors.
The goal of the present study was to investigate the effect of some factors on somatic cell count in milk: sire of dairy cow, heritability, agricultural enterprise, milking technique, working operations performed by the milker, calving month, lactation number.
The experimental farms were chosen from agricultural enterprises applying different cow-keeping and milking technologies. Daughters of 21 bulls were studied. The data about ten-month milk yield, somatic cell count, fat and protein content of the milk of the daughters of each bull were collected. Cow' s sire, enterprise, lactation, milking equipment and milking operator were fixed in data-base. Monitoring of the working operations of the milkers were carried out. The duration of each element of the working process was recorded. SAS-program was used for data processing. Procedure REML was used to estimate the dispersion components and heritabilities. From these data analysis we can made following conclusions.
The milk somatic cell count increases with lactation number (P<0.01). In first lactation the milk somatic cell count was 285 000/ml, in second, third and fourth lactation 321 000/ml, 466 000/ml and 477 000/ml, respectively.
The milk somatic cell count correlation between the neighbour lactations was high: between first and second lactation (r=0.45***), between second and third lactation (r=0.49***) and between third and fourth lactation (r=0.51***).
The agricultural enterprise and the milker were essential to milk somatic cell count (P<0.001).
The adequate premilking cow preparation was essential to milk somatic cell count as well as over-milk-ing (P<0.001).
The delay in application of the milking unit increased milk somatic cell count.
The calving month and the milking equipment were not statistically significant to the milk somatic cell count.
The heritabilities in the first, second, third and fourth lactation were accordingly 0.11, 0.16, 0.23 and 0.23.