Relationship between udder health and hygiene on farms with an automatic milking system

Poor hygiene is an important risk factor for reduced udder health. Because the teat cleaning process is done automatically on farms with an automatic milking system (AMS), hygiene management might differ. The aim of this study was to determine the relationship between hygiene and udder health on farms with an AMS at the farm level as well as at the cow level. Information on hygiene and udder health was collected on 151 Dutch dairy farms with an AMS. Teams of 2 veterinary students collected data with the use of a partially open-ended questionnaire and scoring protocols for hygiene of the cows, cleanliness of the AMS, and functioning of the AMS. Milk production records from the Dutch dairy herd information association were also collected. Stepwise general linear models were used to analyze the relation between hygiene and udder health at farm level. Dependent variables were average herd somatic cell count (SCC), the average percentage of new cows with a high SCC, and the incidence rate of clinical mastitis, all in the year preceding the farm visit. The annual average herd SCC was positively related to the proportion of cows with dirty teats before milking and the proportion of cows with dirty thighs. The annual average percentage of new cows with a high SCC was positively related to the proportion of cows with dirty teats before milking and the proportion of milkings where teats were not covered with teat disinfecting spray by the AMS. The annual incidence rate of clinical mastitis was positively related to the frequency of replacing the milking filters. At the cow level, hygiene scores of the udder, thighs, and legs (range 1 to 4, where 1 is clean and 4 is very dirty) were related with cow SCC from the milk production test day closest to the farm visit using a general linear mixed model. The relationship between cow SCC and the hygiene score of the udder was positive.     

Evaluation of a postmilking teat disinfectant containing a phenolic combination for the prevention of mastitis in lactating dairy cows

A trial was conducted for 12 months in a herd of 120 Holstein cows in order to determine the efficacy of a teat disinfectant, which contained a phenolic combination, for the prevention of bovine intramammary infections during lactation. Postmilking teat disinfection was compared to a negative control using a split-udder experimental design. The percentage of quarters newly infected by mastitis pathogens was 45% lower in mammary glands with teats that had been dipped in the experimental teat disinfectant after milking than it was in undipped controls. New infections caused by Streptococcus uberis, Staphylococcus aureus, coagulase-negative Staphylococcus species, and Corynebacterium bovis were significantly lower in mammary glands with teats that had been dipped in the experimental teat disinfectant than in undipped controls. No statistical differences in the incidence of clinical mastitis between treatment groups were observed. No irritation or chapping of teats dipped in the experimental teat disinfectant were observed. The results of this study suggest that the experimental teat disinfectant containing a phenolic combination is an effective postmilking teat disinfectant for use in the prevention of new intramammary infections by both contagious and environmental mastitis pathogens.     

Farm-level risk factors for bovine mastitis in Dutch automatic milking dairy herds

Automatic milking systems (AMS) are installed on a growing number of dairy farms worldwide. Management to support good udder health might be different on farms with an AMS compared with farms milking with a conventional milking system, as risk factors for mastitis on farms using an AMS may differ. The aim of this study was to identify farm level factors associated with mastitis on Dutch dairy farms using an AMS. In 2008, risk factor data were collected using a questionnaire combined with on-farm recordings of cow, stall, and AMS hygiene on 135 farms. These risk factor data were linked to 4 udder-health-associated dependent variables: average herd somatic cell count (HeSCCav), variance of the average herd somatic cell count (SCC) on test days (HeSCCvar), the average proportion of new high SCC cases (NHiSCC), and the farmer-reported annual incidence rate of clinical mastitis (IRCM). We employed regression models using multiple imputation to deal with missing values. Due to the high dimensionality of the risk factor data, we also performed nonlinear principal component analysis (NLPCA) and regressed the dependent variables on the principal components (PC). Good hygiene of cows and of AMS were found to be related to a lower HeSCCav and less NHiSCC. Effective postmilking teat disinfection was associated with a lower NHiSCC. A higher bulk tank milk SCC threshold for farmers' action was related to more NHiSCC. Larger farm size was related to lower HeSCCvar but higher NHiSCC. Negative attitude of farmers to animal health, higher frequency of checking AMS, and more time spent on viewing computer data were all positively related to higher IRCM. An NLPCA with 3 PC explained 16.3% of the variance in the risk factor variables. Only the first 2 PC were associated with mastitis. The first PC reflected older and larger farms with poor cow hygiene and AMS hygiene, and was related to higher HeSCCav and NHiSCC, whereas the second PC reflected newly built smaller farms with poor cow hygiene and low milk production, and was associated with higher HeSCCvar and NHiSCC, but lower IRCM. Our study suggests that many of the risk factors on conventional milking system farms are applicable to AMS farms, specifically concerning hygiene of the cows and the milking machine, but on large AMS farms, udder health may need more attention than on smaller AMS farms. Multiple imputation is instrumental to deal with missing values and NLPCA is a useful technique to process high dimensional data in our study.     

Premilking teat disinfection: Is it worthwhile in pasture-grazed dairy herds?

A controlled trial was conducted in 5 pasture-grazed commercial dairy herds in Australia in 2012 to determine whether premilking teat disinfection and drying of teats reduces clinical mastitis incidence during early lactation by at least 50%. A 50% reduction was estimated to be the minimum required to justify additional costs of labor, disinfectants, and other resources if premilking teat disinfection was implemented in a 500-cow herd averaging 8 clinical cases per 100 cow-months. A secondary aim was to determine whether this premilking teat disinfection routine reduces incidence of new udder infections. Treatment was applied in each herd for approximately 60 d (range of 59.5 to 61 d), commencing in each herd soon after the start of the herd's main or only calving period. Within each herd, cows were allocated to either the treatment (premilking disinfection) or the control (no premilking disinfection) group based on their herd identity number. During the trial period, any cow having a new case of clinical mastitis or an individual cow cell count greater than 250,000 cells/mL of milk (when preceded by individual cow cell counts of 250,000 cells/mL of milk or below) was deemed to have had a new infection. Overall, neither clinical mastitis incidence nor new infection rate differed significantly between treatment and control groups. Over the whole study period, 98 of the 1,029 cows in the premilking disinfection group and 97 of the 1,025 cows in the control group had clinical mastitis. Total cow-days at risk of clinical mastitis were similar in each group. However, clinical incidence rates were markedly lower in treatment cows in one herd (herd 3; incidence rate ratio = 0.34) and there was some evidence that new infection incidence rates were lower in treated cows in this herd (incidence rate ratio = 0.42). Rainfall during the study period was below long-term district average in all 5 study herds. Cows’ teats were less dirty than in previous, wetter years for the 4 herds where no significant clinical mastitis response was detected but some teat soiling was observed in herd 3 during the study period. Routine application of premilking teat disinfection in pasture-grazed herds is unlikely to produce a worthwhile (economic) reduction in the number of clinical mastitis cases when teats are relatively clean and dry and the clinical mastitis incidence is low. However, premilking disinfection might be worthwhile during periods when teats are heavily soiled and the incidence of clinical mastitis due to environmental pathogens is high.     

Visual detection of technical success and effectiveness of teat cleaning in two automatic milking systems

Technical success and effectiveness of teat cleaning and the management factors associated with them were evaluated in 9 automatic milking herds. In total, 616 teats cleaned with a cleaning cup and 716 teats cleaned with rotating brushes were included. Technical success and the effectiveness of teat cleaning, including the location and nature of the dirt, were evaluated visually. On average, 79.9% of teat cleanings with a cleaning cup, and 85.0% of those cleaned with brushes succeeded technically; that is, the teat was correctly positioned in the cleaning device throughout the whole cleaning process. The difference between use of teat cups and brushes was significant. However, because technical success of teat cleaning is strongly dependent on herd characteristics, these results should be interpreted with caution. Factors associated with the technical success of teat cleaning with a cleaning cup were herd, days in milk, behavior of the cow, teat color, and teat location. For rotating brushes, behavior of the cow, teat location, udder and teat structure, and days in milk were associated with technical success. Excessive udder hair and technical failure of the automatic milking machine also caused a few technically unsuccessful teat cleanings with a cleaning cup. Teats with technically successful teat cleanings were evaluated for the effectiveness of teat cleaning. From originally dirty teats, the cleaning cup had a significant advantage over the brushes in the percentage of teats that became clean or almost clean during the cleaning process (79.8 vs. 72.9%). Teat orifices were least effectively cleaned compared with the teat barrel and apex. Bedding material (peat, sawdust, or straw) on the teat was cleaned almost completely. Factors associated with the effectiveness of teat cleaning were teat cleanliness before cleaning, herd, teat cleaning method, and teat condition. The variation among herds indicates the likelihood that herd management factors can be adjusted to improve milking hygiene. There is also a need to improve the precision and effectiveness of the teat cleaning mechanisms of automatic milking systems.     

Efficacy of chlorhexidine as a postmilking teat disinfectant for the prevention of bovine mastitis during lactation

A natural exposure trial was conducted for 12 mo in a herd of 150 lactating Jersey cows to determine efficacy of a .35% chlorhexidine teat dip containing a glycerine emollient for the prevention of bovine intramammary infections. Right teats of cows were dipped in the experimental teat dip after milking machine removal and left teats were not dipped. The herd was free of Streptococcus agalactiae and had a low prevalence of Staphylococcus aureus. Most new major pathogen intramammary infections resulted from Streptococcus species, primarily Streptococcus uberis and Streptococcus dysgalactiae. New infections by Streptococcus species were significantly lower in teats dipped in chlorhexidine than in undipped teats. Overall efficacy of the chlorhexidine teat dip against major mastitis pathogens was 50%. The experimental teat dip also reduced coagulase-negative Staphylococcus species infections 49.0% and Corynebacterium bovis infections 65.2%. Overall efficacy against minor mastitis pathogens was 54.0%. No irritation or chapping of teats dipped in the experimental teat dip was observed.     

Milk yield, somatic cell counts, and risk of removal from the herd for dairy cows after covered teat canal injury.

The objective of this study was to evaluate milk yield, somatic cell count (SCC), and risk of removal of a cow from the herd after covered teat injury. Teat injuries were diagnosed and treated by using endoscopy. After treatment, teats were rested for 3 x 3 d. Eighty-one cows referred to the Veterinary Clinic Babenhausen were used for this study. Each cow was matched to three herdmates by breed, age, and calving date. Data on milk yield and SCC were available from the records of the Bavarian milk control board. Test day milk yields and lactational milk yields were equal for cows with covered teat injury and herdmates in the lactation when the injury was diagnosed and in the subsequent lactation. Calving interval in the year the injury was diagnosed and the time cows lived in the herd were also equal. However, covered teat injuries significantly increased test day SCC by 128,000 cells/ml of milk. These injuries also significantly increased the odds of subclinical mastitis (SCC > 100,000 on test day) and the odds of violating European milk shipping regulations (SCC > 400,000 on test day). Because increased SCC was significantly associated with decreased milk yield, cows may not have fully utilized their milk yield capacity after covered teat injury.     

Cow-related risk factors for milk leakage

Milk leakage in dairy cows is a symptom of impaired teat sphincter function. Milk leakage is related to an increased risk of mastitis in heifers and cows, and causes hygiene problems. The aim of our study was to assess whether teat shape, condition of teat orifice, and peak milk flow rate are risk factors for milk leakage. We conducted a longitudinal observational study in 15 German dairy farms in which cows were maintained in loose housing. The farms were visited monthly at 2 consecutive milkings. During the evening milking, milk flow curves were measured with the LactoCorder. Milk leakage was recorded during the subsequent morning milking, when cows entered the milking parlor. Immediately after detachment of the milking cluster, teat shape, teat end shape, and condition of the teat orifice of cows were assessed between 9 and 100 d in milk (DIM) and during late lactation (>250 DIM). Data from 1600 cows were analyzed. Milk leakage was treated as the binary response variable in a logistic regression model with herd as a random effect. Primiparous cows with high peak milk flow and teat canal protrusion were at greater risk of milk leakage. High peak milk flow rate, short teats, teat canal protrusion, inverted teat ends, and early lactation increased the risk of milk leakage in multiparous cows. Random herd effects accounted for only 10% of the total variation, indicating that the impact of management or other herd-level factors on the occurrence of milk leakage is virtually negligible for practical purposes.     

Short communication: Dipping efficiency and teat dip residues in milk using an automatic dipping system

Prototypes of the automatic-dipping system Apollo were tested with the IQ milking cluster (GEA Farm Technologies GmbH, Bönen, Germany) to determine the teat-dip residues in the milk and the dipping performance (number of dipped teats) of the system compared with manual (hand) dipping. A laboratory trial and a field trial at a dairy farm were performed to determine the iodine level in the milk when an iodine-based teat dip was used. In the laboratory trial, the mean difference between the 53 paired samples (sampling upstream and downstream of the cluster) was 18.9 ± 3.18 μg of iodine/kg. A field trial at a 300-cow commercial dairy farm consisted of taking 2 sets of individual cow milk samples 6 wk apart. Three weeks before the second test day, the iodine-based teat dip was replaced by an iodine-free teat dip. The mean difference between the 2 sets of 55 samples was 25.1 ± 5.22 μg/kg. Compared with manually applying an iodine-based teat dip, the increase in the iodine content resulting from the use of the tested cluster with automatic dipping was very low and would not be an issue of food safety. The dipping performance tests were completed on the same 300-cow commercial dairy farm as the field iodine level trial was performed. In total, 4,541 teats from 307 cows were observed on 4 consecutive days, showing a 91.6 ± 1.3% success rate.     

Manageable risk factors associated with bacterial and coliform counts in unpasteurized bulk milk in Flemish dairy herds

Associations between herd management practices and both bacterial counts (BC) and coliform counts (CC) from 254 and 242 dairy herds in Flanders (Belgium), respectively, were studied. Data were analyzed using multivariable, multilevel linear regression analysis, allowing variance components analyses. Both BC and CC fluctuated throughout the year, although the milk quality parameters followed an opposite pattern. Bacterial count values decreased with each increase of the cleaning frequency of the cubicles (once per week, once per day, twice per day, or more than twice per day) between January and March. Herds with a conventional milking parlor had substantially lower BC than herds where the cows were milked using an automatic milking system. Lower BC were observed when the milking parlor was equipped with an automatic cluster removal system, when premilking teat disinfection was applied, when the dry cows were supplemented with a mix of minerals and vitamins, and when the teats were prepared either first wet and dried or via an automatic milking system. Milking cows with a high-pipeline milking parlor setup or with an automatic milking system was associated with substantially higher CC values. Herds where prepartum heifers were often treated with antimicrobials before calving had a lower CC than farms where heifers were either not or only rarely treated. Most variation in BC and CC resided at the herd level rather than at the observation level, indicating that management is important in the control of both BC and CC. Still, only a small proportion of the total variance was explained by factors capturing information related to the milking, herd health, and dry cow management, which suggests that the bacteriological milk quality and, in particular, CC is primarily driven by other factors than the ones included in this study.     

Comparative evaluation of SIMPL silicone implants and NIT natural teat inserts to keep the teat canal patent after surgery

The objective of this study was the comparative evaluation of SIMPL silicone implants and NIT natural teat inserts to keep the teat canal patent after teat surgery. The study was performed on 100 teats of 97 cows treated surgically for milk flow disorders. After surgery, 53 teats were administered with SIMPL and 47 with NIT, and rested for several days. Before treatment and 1 and 6 mo later quarter milk flow and milk yield were measured with Lactocorders; quarter milk was examined for somatic cell count (SCC), pathogens, and signs of mastitis (SCC > 100,000 and pathogens detected). Half a year after surgery milk flow, milk yield and SCC were equal from teats that had been inserted with SIMPL or NIT. The odds of detecting pathogens or signs of mastitis in the milk was lower in SIMPL than in NIT teats at this point in time. SIMPL teats stayed in the herd as long as NIT teats. Based on the results, it may be expected that teats inserted with a SIMPL or NIT do not differ long term in regards to milk flow, milk yield, SCC, and risk of removal from the herd. After the use of SIMPL, fewer pathogens may be detected in the milk long term than after the use of NIT.     

Short communication: Effect of automatic postmilking teat disinfection and cluster flushing on the milking work routine

The importance of a consistent and comprehensive milking routine as a critical component of any mastitis control program is well documented. However, as pressure on time increases, farmers are faced with 3 options: (1) adjust the milking routine to suit the time available, (2) undertake the task less thoroughly, or (3) examine which elements of the milking routine can be automated and substitute capital expenditure for labor. A study was undertaken on 5 farms in the United Kingdom in October and November 2007 to assess the effect on milking time of installing a commercial automatic postmilking teat disinfection and cluster back flushing system (ADF). Two of the farms recruited for the study were intending to purchase the ADF system in the near future and 3 farms had already invested in the technology. The farms ranged in size from 120 to 550 cows and included three 90° rapid exit parlors, a herringbone parlor, and an abreast parlor. All 5 farms were visited for 2 successive milkings before the ADF was installed or disabled, and a detailed time and motion analysis was undertaken. After ADF was installed or the system reactivated, a further 2 milkings were monitored. All monitored farms showed a measurable reduction in milking time after the ADF system was installed. However, the magnitude of the reduction was greater than would be expected by simply removing the elements of postmilking teat disinfection and cluster sanitization. The benefits of ADF are greater than simply disinfecting teats and back flushing clusters and the time saving obtained may allow a more structured milking routine that may have additional benefits in terms of mastitis prevention and control.     

Factors associated with productivity on automatic milking system dairy farms in the Upper Midwest United States

The objective of this study was to identify housing and management factors associated with productivity on automatic milking system (AMS) dairy farms measured as daily milk yield/AMS and daily milk yield/cow. Management, housing, and lameness prevalence data were collected from 33 AMS farms in Minnesota and Wisconsin during a farm visit. All farms in the study used free-flow cow traffic. Mixed model analysis of cross-sectional data showed that farms with automatic feed push-up via a robot produced more milk per AMS/day and per cow/day than farms where feed was pushed up manually. New versus retrofitted facility, freestall surface, manure removal system, and the number of AMS units/pen were not associated with daily milk yield per AMS or per cow. Cow comfort index (calculated as number of cows lying down in stalls divided by total number of cows touching a stall) was positively associated with daily milk yield/cow. Prevalence of lameness and severe lameness, number of cows per full-time employee, depth of the area in front of the AMS milking station, and length of the exit lane from the AMS milking station were not associated with daily milk yield per AMS or per cow. Multivariable mixed model analysis of longitudinal AMS software data collected daily over approximately an 18-mo period from 32 of the farms found a positive association between daily milk yield/AMS and average age of the cows, cow milking frequency, cow milking speed, number of cows/AMS, and daily amount of concentrate feed offered/cow in the AMS. Factors negatively associated with daily milk yield/AMS were number of failed and refused cow visits to the AMS, treatment time (the time spent preparing the udder before milking and applying a teat disinfectant after milking), and amount of residual concentrate feed/cow. Similar results were also found for daily milk yield on a per cow basis; however, as it would be expected, average days in milk of the herd were also negatively associated with daily milk yield/cow. These findings indicate that several management and cow factors must be managed well to optimize AMS productivity.     

Colonization by Staphylococcus aureus on chapped teat skin: effect of iodine and chlorhexidine postmilking disinfectants.

The abilities of common postmilking teat disinfectant solutions and a teat skin ointment to retard Staphylococcus aureus colonization and promote healing of chapped skin were studied. Ten Holstein cows, free of S. aureus intramammary infections and mammary epidermal colonization, were used. All teats were experimentally chapped with 1N sodium hydroxide and dipped in S. aureus broth culture of 5 x 10(6) cfu/ml after three consecutive milkings. Postmilking teat disinfectant treatments were applied, starting after the second application of S. aureus broth culture, and were continued for the next 19 milkings. Quarters of each cow received one of the following postmilking teat treatments: 1% iodine plus 10% glycerin solution; .5% chlorhexidine plus 4.87% glycerin solution; 1% chlorhexidine ointment; and no postmilking treatment. After milking and before treatment application, samples of skin swabbings of the teat end and teat side and samples of milk were collected. Daily teat skin chapping visual scores were made to assess chapping and healing. Teat skin chapping decreased with time, and the decline was similar among treatments. The concentration of S. aureus recovered from teat skin swabbing solutions decreased over time. Staphylococcus aureus were recovered at significantly lower concentrations from swabbing solutions of teats that were dipped with iodine and chlorhexidine solutions as compared with untreated teats. Staphylococcus aureus was in marginally higher concentrations on ointment-treated teats than on dipped teats. Results indicate the importance of using postmilking teat dips on chapped teats and suggest no advantage in applying a disinfectant ointment to chapped teats to reduce S. aureus colonization and improve skin healing.     

Effects of an automatic postmilking teat dipping system on new intramammary infections and iodine in milk

A technology of automatically applying a postmilking teat dip via the milking machine prior to machine detachment was compared to manual postmilking teat dipping with a teat dip cup for effects on new IMI and iodine content in milk. One hundred twenty Holstein cows were experimentally challenged in a 22-wk trial with Streptococcus agalactiae and Staphylococcus aureus and 148 Holstein cows were experimentally challenged with Streptococcus uberis in another 22-wk trial. The bacterial suspensions were applied to teats of all of the cows after premilking udder preparation and immediately prior to milking machine attachment. In both trials, cows were divided among four treatments: no postmilking teat dipping; manual postmilking teat dipping with a proven efficacious iodophor teat dip; manual postmilking teat dipping with an iodophor teat dip formulated for an automatic postmilking teat dipping system; and automatically postmilking teat dipping via milking machines with an iodophor teat dip formulated for the automatic postmilking teat dipping system. The postmilking teat dipping treatments reduced new Staph. aureus IMI by 64.5, 76.5, and 88.2%; new Strep. agalactiae IMI by 61.5, 77.8, and 94.4%; and new Strep. uberis IMI by 63.5, 82.5, and 93.8%, respectively, against the treatment of no postmilking teat dipping. The treatment applying the postmilking teat dip automatically via milking machines had the lowest number of new IMI caused by the three pathogens. Teat end and teat skin condition were characterized as normal at the end of the study with no differences between treatments. There were no differences with regard to iodine content in milk between treatments.     

Technical note: Effects of attachment of hind teats before cleaning and attachment of front teats on milking characteristics in automatic milking systems

Milking characteristics differ between the 4 quarters of a dairy cow udder. In particular, milking time is mostly prolonged in hind quarters compared with front quarters because of the usually higher amount of stored milk. The standard milking routine (STDMR) in both conventional and automatic milking systems (AMS) consists of teat preparation of all 4 quarters, followed by attachment of the 4 teat cups, regardless of the distribution of milk between quarters. In the current study, an alternative teat preparation and milking routine (ALTMR) in AMS was tested, which consisted of cleaning and starting the milking of hind teats before cleaning and attachment of front teats. The hypothesis was based on the fact that hind quarters have usually a longer milking time than front quarters. Starting the milking of hind quarters while the front teats are being cleaned may reduce the difference in the end of milking between front and hind quarters and thus reduce total milking time. Both routines were tested on 5 Swedish dairy farms equipped with AMS in a 4-wk experiment in which treatments were alternated weekly. Total milk yield did not differ between treatments. Machine-on time (MOT) was longer in ALTMR than in STDMR because the difference in milking time between hind and front quarters was less than the time needed to prepare the front teats. However, the longer MOT in ALTMR was compensated by a shorter total preparation time, including the attachment of the first teat cup, as only the hind teats (instead of all 4 teats) were cleaned before milking was started. This resulted in a similar total milking time from start of cleaning of the first quarter until the end of milking of the last quarter in both treatments. Because of the prolonged MOT, average milk flow rate was lower in ALTMR than STDMR. Peak flow rate was higher in ALTMR than STDMR, but only in teat cups 1 (first attached, hind quarter) and 3 (third attached, front quarter), whereas main milk flow was higher in ALTMR than STDMR in both front quarters. In conclusion, splitting teat cleaning and the start of milking between hind and front quarters does not prolong total milking time, including teat cleaning. The partially positive effect on peak and main milk flow indicates that the ALTMR is a suitable milking routine in AMS. In herds with a greater difference of milk stored in hind compared with front quarters, a reduced total milking time can be expected for ALTMR.     

Short-term effect of transition from conventional to automated milking on teat skin and teat end condition

A higher milking frequency, as a consequence of milking with an automated milking system, incorporates a threat to teat condition. To study the effect of transition from conventional to automated milking on teat skin and teat end condition, 40 lactating Holstein-Friesian cows and heifers from a high yielding dairy herd were randomly allocated to either a conventional or an automated milking system group. In the latter group, automated milking was initiated during the study period, while conventional milking was continued in the control group. Teat skin and teat end condition were evaluated weekly on quarter level for all animals from 5 wk before until 8 wk after transition. A high emollient iodine teat dip was used on all cows during the study period. Teat skin condition of the animals in the automated milking system group was consistent from before and during milking with the automated milking system. Rear teats had a better skin and end condition than front teats. Evolution of teat end condition over time between the automated and conventional milking groups was not statistically different. Heifers, however, seemed to be more sensitive to the change than multiparous cows, as their teat end condition slightly decreased.     

Short communication: Teat skin pH

Changes in teat skin surface pH were studied over 12 wk in 99 lactating Holstein cows. Half the udder of each cow routinely received postmilking disinfection, and the other half served as control. Measures of pH were made on all teats at weekly intervals. Teat skin pH was affected by treatment but not week. Mean teat skin pH measures were: 7.18 (+/- 0.64) and 7.53 (+/- 0.46) for treatment and control teats. In study II, pH teat skin measures were made hourly on 16 cows, starting 2 h before milking, immediately before a milking, immediately after a milking, and for 2 h postmilking. Teat skin pH was significantly lower for treatment teats and was lower for all teats postmilking.     

The Canadian National Dairy Study 2015—Adoption of milking practices in Canadian dairy herds

Several studies have investigated which management practices have the greatest effect on udder health, but little information is available on how broadly the recommended milking practices are adopted across Canada. The National Dairy Study 2015 was designed to gather dairy cattle health and management data on dairy farms across Canada. The objectives of the present study were to describe the current proportions of adoption of milking practices on Canadian dairy farms, and identify factors associated with their use on farms. A bilingual questionnaire measuring use of various practices, including an udder health-specific section, was developed and sent to all Canadian dairy farms. The questions in the udder health section of the questionnaire were adapted from a bilingual questionnaire previously validated and containing questions regarding general milking hygiene and routine, and on-farm mastitis management. Chi-squared tests were used to investigate simple associations between adoption of practices and various explanatory variables including region, milking system, herd size, and bulk tank somatic cell count. In total, 1,373 dairy producers completed the survey. The regional distribution of the participants was representative of the Canadian dairy farm population, and milk quality was, on average, similar to nonparticipants. Overall, Canadian dairy producers followed the recommendations for milking procedures, but some were more extensively used than others. Fore-stripping, cleaning teats, wiping teats dry, using single-cow towels, and use of postmilking teat disinfectant were widely adopted. Use of gloves and glove hygiene, use of a premilking teat disinfectant, and use of automatic takeoffs were not as extensively implemented. Adoption percentages for several practices, including use of gloves, use of a premilking teat disinfectant, teat drying methods, and use of automatic takeoffs were significantly associated with milking system, herd size, and region. It would be helpful to explore the reasons why producers choose to adopt or ignore recommended milking practices as most are easy to include in the routine and are fairly inexpensive.