Post-milking Teat Disinfection Research Articles

Survey of farm, parlour and milking management, parlour technologies, SCC control strategies and farmer demographics on Irish dairy farms

BackgroundThis cross-sectional study describes a survey designed to fill knowledge gaps regarding farm management practices, parlour management practices and implemented technologies, milking management practices, somatic cell count (SCC) control strategies, farmer demographics and attitudes around SCC management on a sample of Irish dairy farms.ResultsWe categorized 376 complete responses by herd size quartile and calving pattern. The average respondent herd was 131 cows with most (82.2%) operating a seasonal calving system. The median monthly bulk tank somatic cell count for seasonal calving systems was 137,000 cells/ml (range 20,000 – 1,269,000 cells/ml), 170,000 cells/ml for split-calving systems (range 46,000 – 644,000 cells/ml) and 186,000 cells/ml for ‘other’ herds (range 20,000 – 664,000 cells/ml). The most common parlour types were swing-over herringbones (59.1%) and herringbones with recording jars (22.2%). The average number of units across herringbone parlours was 15, 49 in rotary parlours and two boxes on automatic milking system (AMS) farms. The most common parlour technologies were in-parlour feeding systems (84.5%), automatic washers on the bulk tank (72.8%), automatic cluster removers (57.9%), and entrance or exit gates controlled from the parlour pit (52.2%). Veterinary professionals, farming colleagues and processor milk quality advisors were the most commonly utilised sources of advice for SCC management (by 76.9%, 50.0% and 39.2% of respondents respectively).ConclusionsIn this study, we successfully utilised a national survey to quantify farm management practices, parlour management practices and technology adoption levels, milking management practices, SCC control strategies and farmer demographics on 376 dairy farms in the Republic of Ireland. Rotary and AMS parlours had the most parlour technologies of any parlour type. Technology add-ons were generally less prevalent on farms with smaller herds. Despite finding areas for improvement with regard to frequency of liner changes, glove-wearing practices and engagement with bacteriology of milk samples, we also found evidence of high levels of documentation of mastitis treatments and high use of post-milking teat disinfection. We discovered that Irish dairy farmers are relatively content in their careers but face pressures regarding changes to the legislation around prudent antimicrobial use in their herds.

Randomized noninferiority field trial evaluating a postmilking teat dip for the prevention of naturally occurring intramammary infections

The aim of this study was to perform a positive-controlled field study under natural exposure conditions to test the efficacy of a newly developed chlorine dioxide-based postmilking teat disinfectant (experimental product, EX) for noninferiority compared with an already established chlorine dioxide-based teat disinfectant (positive control product, PC). After blocking by parity, approximately 200 Holstein cows in early to mid-lactation stages from a dairy farm near Padua, Italy, were randomly assigned to one of 2 groups. Over a 13-wk period between September and December 2021, the teats of cows were dipped with the EX or the PC after each milking. Milk samples were collected from individual quarters of enrolled cows for 13 wk to determine infection status. Teat condition was assessed at wk 1, 5, and 9. Mixed logistic regression was used to analyze the effect of treatment on the incidence of new intramammary infections. For the noninferiority analysis, the upper limit of the 95% confidence interval for the difference in new intramammary infection (NIMI) rate between the 2 treatments (EX - PC) had to be to the left of the critical value d (0.035) to conclude that EX was noninferior to PC in terms of the risk of NIMI. The results showed that the incidence of new infections in the quarters treated with EX (3.1%) was not different from that in the udder quarters treated with PC (2.6%). No overall difference was found between the treatments in terms of teat condition. As the upper limit of the 95% confidence interval of the NIMI rate difference was smaller than the predefined noninferiority limit, we concluded that the EX was noninferior compared with the PC.

RISK FACTORS ASSOCIATED WITH BOVINE MASTITIS

Identifying danger elements for mastitis is imperative for the improvement of particular techniques to manage and forestall the disease. Considering that these elements might also range between areas and dairy farms, the goal of this work was once to evaluation the fundamental threat elements related with bovine mastitis, each scientific and subclinical, in distinct countries, additionally overlaying epidemiological factors of the sickness such as etiology and prevalence. Factors related with bovine mastitis may additionally be associated to the animal, the environment, herd administration and milking equipment. Risk elements for mastitis related with the animal can also be the depth of the udder, the presence of hyperkeratosis on the teats and udder hygiene. Other elements related with a greater hazard of mastitis, such as a greater wide variety of births/lactations/age, greater lactation stage/days in lactation and greater proportion of Holsteins in the herd. Factors related with decrease possibilities of mastitis are: carrying out a milking line, that is, milking cows with mastitis after wholesome cows or separately, the usage of disposable gloves at some stage in milking, pre-milking teat disinfection, drying teats, post-milking teat disinfection and ordinary protection of milking equipment. Regular mastitis research proceed to be imperative for adapting and creating new equipment for controlling and stopping the disease.

Teat open lesions can lead to challenges at milking time on dairies in the Northeast United States.

During evaluations of teat skin by the authors using National Mastitis Council procedures, teat open lesions (TOL) have been more commonly identified in dairies in the Northeast United States over the last 10 years. The TOL described here are found in all stages of lactation and in any age lactating cow, which is unique from TOL that present mainly in first lactation animals just after calving. Cows with these TOL exhibit more abnormal cow behaviors during the milking event. Based on the authors' subjective field evaluations, dry teat skin condition appears to be a significant risk factor. Although there is a paucity of published literature, the other risk factors that the authors have observed are exposure to wind and significant temperature fluctuations, wet bedding, certain bedding additives, and occasionally mechanical, chemical, or thermal trauma. Teat open lesions have been observed in herds with all the common types of bedding. Treatment and preventative measures have focused on supporting skin conditions through higher emollients in the postmilking teat disinfection (PMTD) and controlling the environmental conditions to which the teat is exposed. This includes an evaluation of cow positioning in the stall as well as bedding levels, which influence bedding contamination. The accuracy of PMTD application can also have an influence. The objective of this narrative review was to search the current literature describing TOL, identify knowledge gaps, describe the authors' field experience with TOL on dairy operations in the Northeast United States, and identify opportunities for future research.

The use of teat disinfectants and milking machine cleaning products in commercial Holstein-Friesian farms.

The aim of our study was to survey and analyze the use of pre- and post-milking teat disinfectants and milking machine cleaning products in large commercial Holstein-Friesian farms. A total of 43 Hungarian dairy farms with 31,430 cows with an average herd size of 731 cows were surveyed in 2014 by using a questionnaire via personal interviews. In the statistical analysis, we used ANOVA models and Tukey's multiple comparison method. Furthermore, seven in-depth individual interviews were conducted with farm managers. The results showed that 83.7% of the farms used different pre-milking disinfection methods (65.1% teat dips) and all of them applied post-milking disinfection. In the herds, chlorhexidine (42.9%) and other chlorine (21.4%) compounds were the most widely used active ingredients in the pre-milking disinfection, while iodine in the post-milking disinfection (53.8%). Lactic acid was ranked second in both disinfections (25.0 vs. 41.0%). In post-milking teat disinfection, the use of iodine and lactic acid combined with other active ingredients showed a significant relationship with SCC (p = 0.0454; p = 0.0113). In the milking machine cleaning process, the most frequently used active ingredients were sodium hypochlorite (80.0%) and sodium hydroxide (60.0%) as caustic detergents, while phosphoric acid (81.3%) as an acidic product. A significant relationship was found between the use of phosphoric acid combined with nitric acid, and the use of a combination of phosphoric acid, nitric acid, and organic acid and SCC (p = 0.0483; p = 0.0477). For farm decision-makers, the most decisive factor in the procurement of teat disinfectants was the active ingredient (3.4 on a scale of 1 to 10 where 1 was the most important), while regarding milking machine cleaning products the price (3.2).

Coagulase-negative staphylococci as an evolving mastitis causing organism in cows: A review

The present review attempts to address the emergence of a fast-growing mastitis causing pathogen – coagulase-negative staphylococci (CNS) – and its multi-facet roles in dairy farms. CNS is divided into numerous species, but only a few succeed in bovine mastitis. The two predominant CNS species causing mastitis are Staphylococcus chromogenes and Staphylococcus simulans. These two mostly known CNS affects dairy cows at varied parities and at different lactation stages. CNS have been judged to be the most common bovine mastitis isolate in several countries of the world. However, CNS may not likely be as pathogenic as the other primary mastitis pathogens such as Staphylococcus aureus and its infection mostly remains subclinical. Conversely, CNS is capable of triggering persistent infections among dairy herds, resulting in reduced milk quality and high milk somatic cell count (SCC). One negative impact of CNS infection in dairy herds is that it can destroy cow udder tissue, hereby leading to a drop in milk production of dairy cows. CNS mastitis has a high cure rate when treated with anti-biotics as their infection in cows are not known to be a therapeutic problem. Judging from several literatures, it cannot be said whether CNS species act as an ecological or contagious pathogens. Regulator procedures, including pre- and post-milking teat disinfection, may reduce contagious mastitis pathogens of CNS infections in the dairy herd. Phenotypic methods for identification of CNS are not adequately dependable, and molecular techniques of identification may be better substitute for identification. Dairy farmers may benefit greatly from more empirical research on the epidemiology of CNS mastitis and more reliable methods for species identification.

Evaluation of Calcarea carbonica derivative complex (M8) on milk parameters in the dairy cow

Background Any dairy herd that continually has a somatic cell count (SCC) above 200,000 cells/ml has an indication of mammary gland inflammation (mastitis). Routine use of antibiotics to prevent mastitis is prohibited by organic farming regulations. This limitation has lead researchers to focus on cows natural defense mechanisms [1]. Calcarea carbonica derivative complex (M8) is a complex high diluted medication comprised of comprised of Calcarea carbonica 16x, Aconitum napellus 20x, Arsenicum album 18x, Asa foetida 20x, Conium maculatum 17x, Ipecacuanha 13x, Phosphorus 20x, Rhus toxicodendron 17x, Silicea 20x, Sulphur 24x, and Thuya occidentalis 19x. Dilution procedures have followed standard methodology described at the Brazilian Homeopathic Pharmacopoeia. This medication has enhanced immune system responses both in vitro and in vivo in a murine model [2]. 
 Aims In the present study, we investigate the response of dairy cows after M8 treatment. 
 Methodology The study was performed as a randomized, observer double-blinded and placebo-controlled trial, with a stratified design, using lactation number and SCC as stratification factors. The study sample consisted of 42 lactating dairy cows (Holstein) in one high producing dairy herd with 52 cows in milk in southern Brazil, divided into two experimental groups (n=21). Exclusion criteria were cows with clinical mastitis or receiving any other medical treatment. Pre- and post-milking teat disinfection was practiced in the herd. All cows were clinically examined, with udder and milk samples being appraised according to Rosenberger (1990) [3]. During 3 months one group received daily M8 treatment, the other placebo. Oral administration of 5 ml/day/cow was performed using an automatic dosage dispenser. Monthly, milk production, SCC, fat and total protein content were carefully recorded for each animal by an official milk recording program. SCC were log transformed for analysis. ANOVA and Tukey test were used to compare the averages. The Bartlett´s test was used for homogeneity of variance evaluation.
 Results There were no significant differences (P=0.435) among the groups in the initial evaluation (Values of SCC x103 : Placebo 67,37±80,48; Treatment 359,39±677,02). After 3 months, the M8 treated group showed a decrease (134,00±178,76 P= 0.047) in SCC when compared with control group (391,71±686,60). Fat and protein did not differ between groups and time analysed. Milk production decreased in the placebo group during time (Before: 34,97±6,69kg; After:28,69±4,33kg), whereas the treatment group did not change total amount (Before: 28,7±6,54kg; After: 26,39±5,73kg; P > 0.05). 
 Conclusions These results indicate that the M8 influenced positively SCC and suggest that it may be considered as a possible tool to promote bovine mastitis prophylaxis.
 Keywords: Calcarea carbonica complex, mastitis, somatic cell count
 [1] McDougall S, Parker KI, Heuer C, Compton CWR. A review of prevention and control of heifer mastitis via non-antibiotic strategies. Vet Microbiol. 2009; 154:177–85. 
 [2] Oliveira CC, Abud APR, Oliveira SM, Guimarães FSF, Andrade LF, Di Bernardi RP, Coletto ELO, Kuczera D, Da Lozzo EJ, Gonçalves JP, Trindade ES, Buchi DF. Developments on drug discovery and on new therapeutics: highly diluted tinctures act as biological response modifiers. BMC Complementary and Alternative Medicine. 2011; 11(101): 2-11. 
 [3]Rosenberger, G. Die klinische Untersuchung des Rindes, 3. Neubearbeitete Auflage, Paul Parey Verlag, Berlin, 1990.

Salvinia auriculata: chemical profile and biological activity against Staphylococcus aureus isolated from bovine mastitis.

The aquatic plant Salvinia auriculata has been shown to possess promising properties for the treatment of Staphylococcus aureus bovine mastitis. The disease affects cattle health and compromises dairy cattle productivity, resulting in reduced milk production and higher mortality rates. The aim of this study was to evaluate the antimicrobial activity, antibiofilm activity, and toxicity of S. auriculata root extracts using bovine mammary epithelial cells (MAC-T); determine the chemical composition of the most active extract; and develop an S. auriculata antiseptic solution for pre- and post-milking teat disinfection. Plants were collected during the four seasons of the year. The most active hexane extract was subjected to bioguided fractionation, which resulted in the isolation of six known compounds, stigmast-22-ene-3,6-dione, stigmasterol, friedelinol, β-sitosterol, octadecyl alcohol, and octadecanoic acid. The antimicrobial and antibiofilm activities of the most active extract and isolated compounds were determined against nine S. aureus strains isolated from cows with mastitis. The efficacy of the S. auriculata teat dip formulation was tested using an excised teat model (ex vivo), and promising results were obtained. The S. auriculata extract formulation proved to be as effective as commercial antimicrobials in reducing log counts in excised teats.

Antimicrobial activity of polyhexamethylene biguanide nanoparticles against mastitis-causing Staphylococcus aureus

Postmilking teat disinfection is one of the main measures used to prevent mastitis caused by contagious pathogens, such as Staphylococcus aureus. The present study evaluated the antimicrobial activity of polyhexamethylene biguanide (PHMB) and PHMB nanoparticles (NP) against mastitis-causing Staph. aureus using a microdilution assay methodology. A total of 20 mastitis-causing Staph. aureus isolates were used to determine the minimum inhibitory concentrations (MIC) of PHMB and PHMB NP compared with 3 disinfectants commonly used for teat disinfection (chlorhexidine digluconate, povidone-iodine, and sodium dichloroisocyanurate). The MIC90 was defined at the concentrations required to inhibit the growth of 90% of Staph. aureus. Our results indicated that PHMB NP presented the lowest MIC value (<0.03 µg/mL) to inhibit 90% of Staph. aureus, followed by chlorhexidine digluconate (≥0.25 µg/mL) and PHMB (≥0.5 µg/mL). On the other hand, sodium dichloroisocyanurate (≥500 µg/mL) and povidone-iodine (≥8,000 µg/mL) presented the highest concentrations to inhibit the growth of most Staph. aureus. Our preliminary results suggested that both PHMB and PHMB NP have antimicrobial activity against mastitis-causing Staph. aureus, which indicates the potential for both to be used as a teat-dip disinfectant to prevent bovine mastitis.

Efficacy of a Lactobacillus-Based Teat Spray on Udder Health in Lactating Dairy Cows.

Teat disinfection is a common pre- and post-milking mastitis prevention practice that is part of a mastitis control program in dairy herds. Commercially available teat disinfectants are generally chemical-based products. The use of these products has occasionally raised concerns about the risk of chemical residues in milk. An alternative treatment or prevention strategy based on probiotics has the potential to circumvent this risk. Two treatments were compared in a cross-over clinical trial in a single herd: a lactobacillus-based, post-milking teat spray (LACT), and a commercial iodine-based post-milking teat disinfectant product as (positive control, PC). The effect of the two treatments on cow somatic cell counts was quantified using a multivariate mixed-effects linear regression model with cow fitted as a random effect. The odds of teat end scores increasing from a low to a high score tended to be lower (OR = 0.74, 95% CI 0.54–1.01, P = 0.06) for cows receiving LACT treatment. On average, there was also a tendency for a lower somatic cell counts in the LACT treated cows (antilog of coefficient = 0.91, 95% CI 0.80–1.03, P = 0.13) compared with the PC treated cows. The application of the lactobacillus-based product to teats could reduce the rate of teat end scores progression from low to higher scores, and potentially improve teat end sphincter functions and udder health. Further, larger scale validation work is required to support the findings of the current study.

Bovine mastitis: risk factors, therapeutic strategies, and alternative treatments - A review.

Bovine mastitis, an inflammation of the mammary gland, is the most common disease of dairy cattle causing economic losses due to reduced yield and poor quality of milk. The etiological agents include a variety of gram-positive and gram-negative bacteria, and can be either contagious (e.g., Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma spp.) or environmental (e.g., Escherichia coli, Enterococcus spp., coagulase-negative Staphylococcus, Streptococcus uberis). Improving sanitation such as enhanced milking hygiene, implementation of post-milking teat disinfection, maintenance of milking machines are general measures to prevent new cases of mastitis, but treatment of active mastitis infection is dependant mainly on antibiotics. However, the extensive use of antibiotics increased concerns about emergence of antibiotic-resistant pathogens and that led the dairy industries to reduce the use of antibiotics. Therefore, alternative therapies for prevention and treatment of bovine mastitis, particularly natural products from plants and animals, have been sought. This review provides an overview of bovine mastitis in the aspects of risk factors, control and treatments, and emerging therapeutic alternatives in the control of bovine mastitis.

Effects of machine milking on udder health in dairy ewes

• Milking machine settings that increase vacuum fluctuations under the teat must be avoided to reduce the intramammary infection risk. • Although a high milk pipeline causes higher vacuum fluctuations at teat level, no relation with bulk milk SCC have been found. • Milking machine settings that increase teat thickness would reduce the local defence mechanisms and should be avoided. • Post-milking teat disinfection, milking animals with intramammary infections last, and avoiding over-milking for longer than 2 min can affect mammary gland health status by reducing the incidence risk of mastitis. The aim of this article is to review factors associated with machine milking that would increase mastitis incidence risk and the effects of milking machine, milking management and routine in sheep. Machine milking settings that increase vacuum fluctuations under the teat or teat thickness and help to disseminate infectious agents would increase the risk of intramammary infection. Vacuum fluctuations are caused by a low effective reserve, low air and milk line diameters, low milk tube diameters, sudden air leakages caused by high milking cluster weight, teatcup slippage, excessive liner mouthpiece diameter or inadequate machine stripping. The milk line height (low vs mid line) has no relation with SCC if the rest of the settings are adequate, although higher vacuum fluctuations have been recorded in high line. The settings that increase teat thickness include an excessively high vacuum level, lack of effective massage on the teat (high pulsation ratio), liners too soft, hard, narrow or old, and overmilking for longer than 2 min. Regarding milking management, the reduction of milking frequency to 1 milking per day has an effect on yield and SCC due to a concentration effect, and some milking practices such as post-milking teat disinfection or milking animals with intramammary infections last, despite the drawbacks in overall farm management (identification and separation of infected animals), can lower the risk of mastitis incidence.

The Benefits of Teat Dipping as Prevention of Mastitis

Mastitis is the major disease and the most costly disease of the dairy industry worldwide. One of the mastitis control programs that until now has been carried out and proven to be quite effective is the teat dipping method as a form of prevention. Various methods and uses of teat dipping solutions have been widely used and used for this purpose such as iodine, potassium permanganate, chlorhexidine, chlorhexidine gluconate chlorine, iodophor, sodium hypochlorite, lactic acid, phenolics and Dodecyl Benzene Sulfonic Acid (DDBSA). Pre milking and post milking teat disinfection have been recommended widely by veterinarians and adopted by dairy producers in increasing numbers. This procedure is simple to perform, economical, and effective in controlling contagious mastitis pathogens. More recently, teat dipping in association with good udder preparation reduced the rate of intramammary infections by environmental pathogens. This paper aims to provide a brief review of the benefits of teat dipping as a method of controlling the incidence of mastitis in dairy cows. Keywords : mastitis, teat dipping, pathogens, intramammary infections

Noninferiority study evaluating the efficacy of a teat disinfectant containing copper and zinc for prevention of naturally occurring intramammary infections in an automatic milking system

The aim of this study was to demonstrate the noninferiority of a novel teat disinfectant based on copper and zinc (ZkinCu; Copper Andino, Santiago de Chile, Chile) compared with a previously proven glycolic acid active disinfectant (OceanBlu; DeLaval, Kansas City, MO) as a positive control, with respect to the incidence of new intramammary infections under natural challenge conditions on a commercial robotic dairy farm. This study was conducted in 6 robotic pens of approximately 60 milking cows each. The pens were randomly assigned to 1 of the 2 studied disinfectants. Throughout the 8 wk study, the same pre- and post-milking teat disinfectant was used in each pen. The same milking procedures were used in each robot throughout the study. Pre-milking hygiene consisted of applying the disinfectant (OceanBlu or ZkinCu) with the robotic arm. The same product was applied on the teats after milking. At the beginning of the study, all quarters of all study cows were sampled. In successive samplings (wk 2, 4, 6, and 8), composite milk samples were collected on farm to determine SCC. Once composite SCC results were available (2 d) and based on an SCC of ≥100,000 cells/mL, quarter milk samples underwent bacteriological culture. Clinical mastitis was identified by study personnel. Intramammary infection in biweekly quarter milk samples was determined based on composite SCC levels (≥100,000 cells/mL) and the presence of bacteria. A new IMI was defined as a quarter in which the organism isolated was not present in the previous bacteriological sample, or the previous composite SCC sample was <100,000 cells/mL. Clinical mastitis samples were also considered to be new IMI. The trial was designed as a positive control field trial, in which the objective was to show noninferiority of ZkinCu versus the control (OceanBlu). The overall crude incidences of new IMI for 2 wk at risk were 4.9 and 7.3% for the ZkinCu and OceanBlu groups, respectively. The predominant organisms recovered from quarters with new IMI were Streptococcus uberis, Corynebacterium spp., and coagulase-negative staphylococci in both the ZkinCu and OceanBlu groups. The risk of infection in the OceanBlu group was higher (β = 0.644; 95% confidence interval = 0.05-1.22). The interaction of treatment by week was not significant. The new IMI rate estimates (95% confidence interval) for ZkinCu and OceanBlu were 1.7% (0.8-2.5) and 3.2% (1.7-4.7), respectively. One novel aspect of this study is that it was one of the first commercial noninferiority trials to evaluate a new pre- and post-milking teat disinfectant in a dairy herd with an automatic milking system. The experimental teat disinfectant ZkinCu, evaluated in this field trial with naturally occurring IMI, showed noninferiority relative to the positive control for the prevention of new IMI. This study was conducted in a herd with an automatic milking system, and the results are applicable to herds with similar characteristics. Additional studies are needed to ensure reproducibility under different management conditions.

“If it ain’t broke don’t fix it”

A large part of preventing mastitis on dairy farms is achieved through the use of recommended milking practices (RMPs) that have been established and promoted by industry and milk quality organizations such as the National Mastitis Council and the Canadian Bovine Mastitis and Milk Quality Research Network. These practices include use of milking gloves, foremilk stripping, use of pre and post milking teat disinfectants, drying teats prior to milking, and use of automatic takeoffs on milking machines. However, many producers do not adopt these measures, or they only do so partially. This study aimed to explore the attitudes and perceptions of Ontario dairy farmers towards barriers for implementation of RMPs, and to investigate what motivates behavior change in relation to milking hygiene.

The importance of teat disinfection in mastitis control

Teat disinfection in dairy herds is an important part of mastitis control, both to reduce infection pressure from the environment and to reduce risk of transmission of infection between cows. Despite much focus on mastitis as an endemic disease, clinical and subclinical mastitis remains an issue for many UK herds, often leading to a perception that changing the teat disinfection product may provide quick solutions. This article summarises the types of products available for both pre- and post-milking teat disinfection, the aim of both types of teat disinfectant and how they may be applied.

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.

Efficacy of a terpinen-4-ol based dipping for post-milking teat disinfection in the prevention of mastitis in dairy sheep

ABSTRACTMastitis is the main cause of antibiotic use in dairy sheep. Post-milking teat disinfection is adopted to prevent intra-mammary infections. Use of chemical disinfectants is associated with biocide and antibiotic resistance. Terpinen-4-ol (T-4-ol), component of the Melaleuca alternifolia essential oil, shows antibacterial properties without inducing resistance. Aim of the trial was to evaluate the efficacy of a T-4-ol post-dipping compound in preventing bacterial mastitis in dairy sheep. In two different farms, two groups of 35 ewes were recruited as experimental and control arm (exposed to chlorhexidine-based disinfectant). No differences were observed during the follow-up. In one livestock, during the first year, 30-day incidence of mastitis was significantly lower in the T-4-ol group. Post-milking teat disinfection with T-4-ol showed equivalent efficacy in terms of mastitis incidence. Disinfectants based on natural compounds for mastitis prevention could potentially reduce environmental pollution, avoid drug residues in milk and decrease the antimicrobial resistance development.

Herd-Level Mastitis-Associated Costs on Canadian Dairy Farms.

Mastitis imposes considerable and recurring economic losses on the dairy industry worldwide. The main objective of this study was to estimate herd-level costs incurred by expenditures and production losses associated with mastitis on Canadian dairy farms in 2015, based on producer reports. Previously, published mastitis economic frameworks were used to develop an economic model with the most important cost components. Components investigated were divided between clinical mastitis (CM), subclinical mastitis (SCM), and other costs components (i.e., preventive measures and product quality). A questionnaire was mailed to 374 dairy producers randomly selected from the (Canadian National Dairy Study 2015) to collect data on these costs components, and 145 dairy producers returned a completed questionnaire. For each herd, costs due to the different mastitis-related components were computed by applying the values reported by the dairy producer to the developed economic model. Then, for each herd, a proportion of the costs attributable to a specific component was computed by dividing absolute costs for this component by total herd mastitis-related costs. Median self-reported CM incidence was 19 cases/100 cow-year and mean self-reported bulk milk somatic cell count was 184,000 cells/mL. Most producers reported using post-milking teat disinfection (97%) and dry cow therapy (93%), and a substantial proportion of producers reported using pre-milking teat disinfection (79%) and wearing gloves during milking (77%). Mastitis costs were substantial (662 CAD per milking cow per year for a typical Canadian dairy farm), with a large portion of the costs (48%) being attributed to SCM, and 34 and 15% due to CM and implementation of preventive measures, respectively. For SCM, the two most important cost components were the subsequent milk yield reduction and culling (72 and 25% of SCM costs, respectively). For CM, first, second, and third most important cost components were culling (48% of CM costs), milk yield reduction following the CM events (34%), and discarded milk (11%), respectively. This study is the first since 1990 to investigate costs of mastitis in Canada. The model developed in the current study can be used to compute mastitis costs at the herd and national level in Canada.

Milking machine and udder health management factors associated with bulk milk somatic cell count in Uruguayan herds

This paper describes the findings of static milking machine tests and milking observations on Uruguayan dairy farms. The aim of this study was to investigate the association between both milking machine performance and udder health management factors and bulk milk somatic cell count (BMSCC) in Uruguayan dairy herds. Data from 907 visits were used for the analysis. The farm visits were made between April 2006 and November 2015 and farms were located in 17 of the 19 departments of Uruguay. Each visit involved a short static machine test and observation of the milking process; the use of blanket dry cow therapy was also recorded. The BMSCC was the variable of interest. Univariable analysis was applied to explore the best set of predictors to be included in the multivariable model. A multivariable linear regression model was fitted. The median BMSCC over the years was 376 thousand cells/mL (interquartile range = 280,000–500,000 cells/mL). The final model showed a lower BMSCC for herds that used post-milking teat disinfection, applied the teat cups to dry teats and maintained the pulsation system in good working order. There was no significant association between BMSCC and blanket dry cow therapy in the final model. The association of these milking machine and udder health management factors with the BMSCC under Uruguayan conditions is relevant information for a dairy industry that needs low BMSCCs to compete on the world market.