engleski

Influence of impropriate milking on udder health of dairy cows

The aim of the study was to compare and analyse influence of different milking failures on udder health of dairy cows. Two dairy farms in southwestern Croatia were observed and followed during five years. At the first farm there were 430 cows and at the second farm there were 320 monitored cows. Cows of both breeds were uniform according to breed, age and milk production ; they all were holstein-frisian cows, approximatly 8 years old, used in milk production for 5-6 years with everage milk production of 7 000 l per year. Cows from the first farm were milked on the milking parlour 3 times daily using „ BOU-MATIC“ system. Unfortunately, due to some technical problems, part of the system didn't work properly and it was necessary to replace it with manual milking during the last two years of research. Due to high hygienic standards of milking preparation, they didn't notice any change of milk hygiene and quality. On the second farm cows were milked 2-3 times daily according to lactation status using milking machines on the lair but presanitation and hygienic standards were very poor and absolutely unsufficient. On both farms mastitis test was performed regularly and milk samples from all positive cows were collected for bacteriological tests. During five years we analysed 1292 samples from the first and 2504 samples from the second farm. After bacteriological test of 1292 samples from the first farm only 18, 60% samples were positive versus 16, 6% positive results from 2504 samples from the second farm. Monitoring and analysis of results from the first farm has shown statistically significant influence of mentioned technical problem on positive results of bacteriological tests. From the 9, 10% positive results at the first year it decreased on 25, 26% at the last year of study. The most common isolate was Staphylococcus aureus (66, 99%), Streptococcus agalactiae (12, 95%), Streptococcus dysgalactiae (4, 88%), Streptoccocus faecalis (8, 06%) and Lactobacillus spp. (7, 09%). Furthermore, number of positive Staphylococcus aureus isolates increased predominatly year after year and caused already mentioned dramatic increase of positive samples. Analysis of results from the second farm has shown that number of positive results decreased slowly from 18, 74% to 16, 66% during five years. There was no predominance of particular bacteria species. The most common isolates were: Streptococcus faecalis (20, 41%), Micoplasma spp. (19, 16%), Streptococcus agalactiae (17, 92%), Staphylococcus aureus (17, 92%), Lactobacillus spp. (9, 58%) and Coliform spp. (8, 75%). Comparation of all positive samples from the front quarters versus rear quarters has shown predominance of the front quarters (55, 41% versus 44, 59%). It could be explained with high incidence of S. aureus who predominantly attacks front quarters. According to our results we concluded that poor sanitation and milking hygiene enables different bacteria and also Micoplasma species to survive at the farm and cause mastitis and dairy losses but in the mean time cows develop sort of resistence wich causes decrease of subclinical infections after a few years. In the mean time, milking of cows using high hygienic standards but changing routine and type of milking ( machine milking replaced with manual milking) causses decrease of immunity and slowly increases subclinical infections. It also enables significant increase of very resistent bacteria like S. aureus to intrude and stay in the farm causing more and more problems and dairy losses.

cow; mastitis; impropriate milking; sanitation; bacteriological test; S. aureus

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