• Effect of liner design, pulsator setting, and vacuum level on bovine teat tissue changes and milking characteristics as measured by ultrasonography

      Gleeson, David E; O'Callaghan, Edmond J; Rath, Myles V (Biomed Central, 2004-05-01)
      Friesian-type dairy cows were milked with different machine settings to determine the effect of these settings on teat tissue reaction and on milking characteristics. Three teat-cup liner designs were used with varying upper barrel dimensions (wide-bore WB = 31.6 mm; narrow-bore NB = 21.0 mm; narrow-bore NB1 = 25.0 mm). These liners were tested with alternate and simultaneous pulsation patterns, pulsator ratios (60:40 and 67:33) and three system vacuum levels (40, 44 and 50 kPa). Teat tissue was measured using ultrasonography, before milking and directly after milking. The measurements recorded were teat canal length (TCL), teat diameter (TD), cistern diameter (CD) and teat wall thickness (TWT). Teat tissue changes were similar with a system vacuum level of either 50 kPa (mid-level) or 40 kPa (low-level). Widening the liner upper barrel bore dimension from 21.0 mm (P < 0.01) or 25.0 mm (P < 0.001) to 31.6 mm increased the magnitude of changes in TD and TWT after machine milking. Milk yield per cow was significantly (P < 0.05) higher and cluster-on time was reduced (P < 0.01) with the WB cluster as compared to the NB1 cluster. Minimum changes in teat tissue parameters were achieved with system vacuum level of 40 kPa and 50 kPa using NB and WB clusters, respectively. Similar changes in teat tissue and milk yield per cow were observed with alternate and simultaneous pulsation patterns. Widening pulsator ratio from 60:40 to 67:33 did not have negative effects on changes in teat tissue and had a positive effect on milk yield and milking time. Milk liner design had a bigger effect on teat tissue changes and milking characteristics than pulsation settings.
    • Effect of pre-milking teat preparation procedures on the microbial count on teats prior to cluster application

      Gleeson, David E; O'Brien, Bernadette; Flynn, James; O'Callaghan, Edmond J; Galli, F (Biomed Central, 2009-07-01)
      A study was carried out to investigate the effect of six pre-milking teat preparation procedures on lowering the staphylococal, streptococcal and coliform microbial count on teat skin prior to cluster application. The teat preparations included 'Iodine', 'Chlorhexidine' teat foam, 'Washing and drying' with paper, 'No preparation', 'Chlorine' teat foam, and disinfectant 'Wipes'. Teat preparations were applied for five days to 10 cows for each treatment during two herd management periods (indoors and outdoors). Teats were swabbed on day four and five before teat preparation and repeated after teat preparation. The swabs were plated on three selective agars: Baird Parker (Staphylococcus spp.), Edwards (Streptococcus spp.), and MacConkey (coliform). Following incubation, microbial counts for each pathogen type were manually counted and assigned to one of six categories depending on the microbial counts measured. The results were analysed by logistic regression using SAS 28. The main analysis was conducted on binary improvement scores for the swabbing outcomes. There were no differences for staphylococcal, streptococcal and coliform bacterial counts between treatments, measured 'before' teat preparation. Treatments containing 'Chlorhexidine' teat foam (OR = 4.46) and 'Wipes' (OR = 4.46) resulted in a significant reduction (P < 0.01) in the staphylococcal count on teats compared to 'Washing and drying' or 'No preparation'. 'Chlorine' teat foam (OR = 3.45) and 'Wipes' (3.45) had the highest probability (P < 0.01) of reducing streptococcal counts compared to 'Washing and drying' or 'No preparation'. There was no statistical difference between any of the disinfectant treatments applied in reducing coliforms. Thus, the use of some disinfectant products for pre-milking teat preparation can have beneficial effects on reducing the levels of staphylococcal and streptococcal pathogens on teat skin.
    • Farm management factors associated with bulk tank somatic cell count in Irish dairy herds

      Kelly, P.T.; O'Sullivan, Kathleen; Berry, Donagh; More, Simon J; Meaney, William J; O'Callaghan, Edmond J; O'Brien, Bernadette (Biomed Central, 01/04/2009)
      The relationship between bulk tank somatic cell count (SCC) and farm management and infrastructure was examined using data from 398 randomly selected, yet representative, Irish dairy farms where the basal diet is grazed grass. Median bulk tank SCC for the farms was 282,887 cells/ml ranging from 82,209 to 773,028 cells/ml. Two questionnaires were administered through face-to-face contact with each farmer. Herd-level factors associated with bulk tank SCC were determined using linear models with annual somatic cell score (i.e., arithmetic mean of the natural logarithm of bulk tank SCC) included as the dependent variable. All herd level factors were analysed individually in separate regression models, which included an adjustment for geographical location of the farm; a multiple regression model was subsequently developed. Management practices associated with low SCC included the use of dry cow therapy, participation in a milk recording scheme and the use of teat disinfection post-milking. There was an association between low SCC and an increased level of hygiene and frequency of cleaning of the holding yard, passageways and cubicles. Herd management factors associated with bulk tank SCC in Irish grazing herds are generally in agreement with most previous studies from confinement systems of milk production.
    • Farm management factors associated with bulk tank total bacterial count in Irish dairy herds during 2006/07

      Kelly, P.T.; O'Sullivan, Kathleen; Berry, Donagh; More, Simon J; Meaney, William J; O'Callaghan, Edmond J; O'Brien, Bernadette (Biomed Central, 01/01/2009)
      Research has shown that total bacterial count (TBC), which is the bacterial growth per ml of milk over a fixed period of time, can be decreased by good hygiene and farm management practices. The objective of the current study was to quantify the associations between herd management factors and bulk tank TBC in Irish spring calving, grass-based dairy herds. The relationship between bulk tank TBC and farm management and infrastructure was examined using data from 400 randomly selected Irish dairy farms where the basal diet was grazed grass. Herd management factors associated with bulk tank TBC were identified using linear models with herd annual total bacterial score (i.e., arithmetic mean of the natural logarithm of bulk tank TBC) included as the dependent variable. All herd management factors were individually analysed in a separate regression model, that included an adjustment for geographical location of the farm. A multiple stepwise regression model was subsequently developed. Median bulk tank TBC for the sample herds was 18,483 cells/ml ranging from 10,441 to 130,458 cells/ml. Results from the multivariate analysis indicated that the following management practices were associated with low TBC; use of heated water in the milking parlour; participation in a milk recording scheme; and tail clipping of cows at a frequency greater than once per year. Increased level of hygiene of the parlour and cubicles were also associated with lower TBC. Herd management factors associated with bulk tank TBC in Irish grazing herds were generally in agreement with most previous studies from confinement systems of milk production.
    • A note on the design and testing of single teatcups for automatic milking systems

      O'Callaghan, Edmond J; Berry, Donagh (Teagasc, Oak Park, Carlow, Ireland, 2008)
      In automatic milking units single independent teatcups or shell/liner combinations are required. The milking characteristics of three designs of single-teatcup milking units were compared with a conventional milking unit in a pipeline milking system. The combined weight of each single-teatcup shell and liner used in the single-teatcup units was 0.18 kg, 0.38 kg or 0.56 kg. The conventional milking cluster had a claw volume of 150 mL and a weight of 3.16 kg. The single sets of teatcups were applied manually and removed automatically when milk flow from the four teatcups reached 0.2 kg/min. The experiment involved a latin square design with four groups of Friesian cows (10 cows/group), four 2-day periods and four treatments. At a flow rate of 4 L/min during simulated milking the mean vacuum level at the teat-end (artificial teat) during the “bphase” of pulsation was 43.8 kPa with the conventional milking unit and 33 kPa for the three single-teatcup units. The corresponding mean and minimum teat-end vacuum in the “d-phase” were 38.46 kPa and 29.54 kPa, respectively, for the conventional system and 24.95 kPa and 17.59 kPa, respectively, for the single-teatcup configuration. The light teatcup (weight 0.18 kg) gave longer time to milk letdown, longer milking time and both lower peak and average milk flow than the conventional cluster.
    • A note on the effects of test-end vacuum on milking characteristics

      O'Callaghan, Edmond J; Gleeson, David E; European Union (Teagasc (Agriculture and Food Development Authority), Ireland, 2004)
      The magnitude of vacuum applied to the teat end can have a major effect on milking characteristics. While milking vacuum is usually measured in the milk pipeline, the teat-end vacuum during milk flow depends on the configuration of the milking unit. The objective was to establish the effect of teat-end vacuum, recorded during flow simulation, on actual milking time, milk yield, and both mean and peak milk-flow rates. Four configurations of milking units were set up to give vacuum levels of 35, 38, 40 and 42 kPa at the apex of an artificial teat during simulated milking. The experiment involved a latin square design with four groups of Friesian cows (14/group), four 2-day periods and four treatments (vacuum level). Altering the vacuum level had no significant effect on milk yield. There were no differences in milking characteristics between vacuum levels of 38 and 40 kPa. A vacuum level of 42 kPa gave a shorter milking time (P < 0.001), higher average milk-flow rate (P < 0.01) and higher peak milk-flow rate (P < 0.001) than the three lower vacuum levels. Milking time was significantly longer (P < 0.001) and peak milk-flow rate lower (P < 0.001) with a vacuum of 35 kPa compared to other vacuum levels.
    • A study of the somatic cell count (SCC) of Irish milk from herd management and environmental perspectives

      O'Brien, Bernadette; Berry, Donagh; Kelly, Philip; Meaney, William J; O'Callaghan, Edmond J (Teagasc, 2009-12-01)
      The objective of this study was to investigate the herd management practices associated with somatic cell count (SCC) and total bacteria count (TBC), to geographically analyse SCC on a national basis, to investigate cow factors associated with SCC and to estimate the milk loss associated with high SCC across parities. From the 400 farms surveyed during farm visits throughout spring and winter, a profile of herd management was developed and the associations between management practices and milk SCC and TBC were established. Management practices associated with low SCC included the use of dry cow therapy, participation in a milk recording scheme, the use of teat disinfection post-milking, a higher frequency of cleaning and increased farm hygiene. Management practices associated with low TBC included the use of heated water in the milking parlour, participation in a milk recording scheme, tail clipping of cows at a frequency greater than once per year and increased farm hygiene. The spatial analysis showed that the south of the country had the greatest density of milk-recording herds. Approximately 60% of all herds in the study were from four counties (Cork, Kerry, Limerick and Tipperary). Average bulk tank SCC increased from 110,264 cells/mL in 2003 to 118,782 cells/mL in 2005, followed by a decrease to 108,454 cells/mL in 2007. Spatial clustering of high SCC scores was not observed (i.e., SCC on one farm was not related to SCC on other farms), which is consistent with mastitis being a herd problem as opposed to an area-based problem. SCC increased with parity from 97,000 cells/mL in parity 1 to 199,000 cell/mL in parity 6. SCC decreased between the period 5 to 35 days in milk (DIM) and 36 to 65 DIM, and increased thereafter. Cows calving in the months of January and September were associated with lower average 305 day SCC. The rate of increase in SCC from mid to late lactation was greatest in older parity animals. There was a test day milk loss of 1.43, 2.08, 2.59, 2.56 and 2.62 litres (parities 1 to 5, respectively) associated with an increase of SCC category from <51,000 to >400,000 cells/mL. When SCC was adjusted (test day SCC/dilution estimate, and test day SCC + (-ß)(test day milk yield)) to account for milk yield, similar trends in milk loss were observed. Alternatively, adjusting SCC (SCC*test day milk yield/mean test day milk yield) to account for milk yield showed an increase in test day milk with increasing SCC category. The results from this study highlight that adherence to best milking/farming practice will help reduce SCC and TBC on farms. The results contribute to the knowledge relating to SCC through increasing the accuracy of milk loss due to SCC and management practices associated with SCC. The results in the study can also be used in the development of strategies to reduce SCC on farms.