This research communication addresses the hypothesis that double premilking teat disinfection (DD) is more effective in reducing soiling and bacterial count on the cows' teat skin and milkers' gloves than conventional disinfection (CONV). The design was a 3 × 3 Latin square (three groups of cows and three treatments) with conventional teat disinfection (CONV, lactic acid application after forestripping), double teat disinfection using the same disinfectant (DD1D, lactic acid application before and after forestripping), and double teat disinfection using two different disinfectants (DD2D, application of lactic acid before and chlorine-based disinfectant after forestripping). All groups were assigned for six days for each treatment, and the evaluations and samples were collected on the last day, before and after treatment. We evaluated the teat cleanliness score (TCS), count of Gram-negative bacteria (coliforms and noncoliforms), Staphylococcus spp., Streptococcus spp., and total bacterial count (TBC) on the cows' teats and TBC on the milkers' gloves. TCS after premilking was lower in DD than CONV treatment. The reduction of Staphylococcus spp. count was greater in the DD treatment and tended to be higher in the DD2D. The TBC reduction on the cows' teats was greater in the DD treatments. The TBC on the milkers' gloves was lower for DD before and after premilking. In conclusion, DD can be an alternative for reducing some bacterial populations on cow teats and preventing the transmission of microorganisms between cows via the milkers' hands.

The objectives of this research were (1) to study different factors affecting milk total bacterial count (TBC) and (2) to estimate the economic value associated with TBC in Holstein dairy herds in Iran. The relationships between bulk tank TBC and farm management and economic factors were examined on 56 randomly selected intensive dairy farms. Herd management factors associated with bulk tank TBC were determined using mixed linear models. The median bulk tank TBC for the sample herds was 299 (range 81–1185) × 103 cfu/ml. The average economic premium opportunity from bulk tank TBC was US$ 1.32 per ton of milk ranging from US$ 0.02 per ton of milk for herds applying wet tissue procedures as teat cleaning material and washing the water troughs three times per day to US$ 5.20 per ton of milk for herds with dirty barns. Results showed that the following management factors were associated with low TBC and high economic value: frequency of cleaning water troughs, teat cleaning material, the frequency of milk delivery to the processor, bedding material, herd size, education level of workers, udder washing material, material of milking parlor wall, frequency of disinfection of the calving area, presence of veterinarian, water quality control, having a hospital pen and barn hygiene. In conclusion, our findings highlight the need to pay more attention to farm management issues, particularly farm hygiene practices to reduce milk TBC and so reduce the economic burden of TBC in dairy herds in Iran.

The objective was to clarify the association between bulk tank milk somatic cell count (BTSCC) and total bacterial count (BTTBC) and coliform bacteria count (BTCBC) in a large set of data based on the currently accepted legal limit of BTSCC=400000/ml. We analysed the database obtained from one of four laboratories offering routine estimation of microbiological indicators and counts of somatic cells in bulk tank milk samples in the Czech Republic during the year 2003 (74174; 73921 and 33020 records of BTSCC, BTTBC and BTCBC estimations, respectively, in milk from 2769 suppliers). Raw data of BTSCC (with arithmetic mean 220000/ml; 95th percentile=502000/ml; 99th percentile=784000/ml) indicated that the BTSCC limit was exceeded in 12% of samples. BTSCC did not sufficiently reflect the hygiene status of particular producing herds because correlation coefficients between bulk tank milk somatic cell score (BTSCS) and log BTTBC or log BTCBC were low. Categorization of herds according to the percentage of records exceeding the BTSCC limit gave significantly higher correlation coefficients for the association between this characteristic and log BTTBC or log BTCBC (r=0·84 and r=0·68, respectively). The percentage of records exceeding the BTSCC limit was a useful tool to highlight problem herds kept in inadequate hygienic conditions in primary milk production. Likewise, the value of BTSCS>5 seemed to be a useful tool for the discrimination of problem herds.