Incidence Of Clinical Mastitis Research Articles

An observational study of farmer-reported clinical mastitis in New Zealand dairy ewes

ABSTRACT Aims To describe the incidence, aetiology, treatment, and outcomes of farmer-reported clinical mastitis on New Zealand dairy sheep farms. Methods A prospective cohort study was conducted on 20 spring-lambing New Zealand sheep milking farms over the 2022–2023 season. Clinical mastitis was defined as a change in the appearance of milk and/or signs of inflammation in the gland. Farmers were required to report all cases of clinical mastitis and collect information on affected ewes’ demographics, clinical features, treatments (where applicable), and outcomes. Milk samples from mastitic glands were submitted for microbiological culture and identification by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF). Results Partial or complete clinical mastitis data were available for 236 cases from 221 ewes on 18/20 study farms. Clinical mastitis was diagnosed in 0–6% of ewes at the farm level, with an overall incidence of 1.8 (95% CI = 1.0–3.2)% using the study data, or 2.3 (95% CI = 1.6–3.3)% using the study data and farmer estimates that included unreported cases. Cases occurred mostly in early lactation, with 59% detected during the lambing period (August–October), at a median of 7 (IQR 3, 40) days in milk. The majority of cases featured clots in the milk (59%), swelling (55%), and unevenness (71%) of the glands. Pyrexia (rectal temperature ≥ 40.0°C) was diagnosed in 25% of cases and depression (lethargy, inappetence, or inability to stand) in 26% of cases. Treatment was given to 46% of cases, with tylosin being the most commonly used treatment (50% of treated cases). The most common outcome was immediate drying off to be culled without treatment (32%), followed by still milking and recovered but with lasting problems (25%). Nearly half of all the milk samples submitted were culture negative. Streptococcus uberis (14%), non-aureus staphylococci (12%), and Staphylococcus aureus (11%) were the most common isolates, found on 12, 8 and 8 of the 16 farms with microbiological data, respectively. Conclusions Clinical mastitis affected up to 6% of ewes at the farm level. Systemic signs were observed in one quarter of affected ewes, suggesting a role for supportive treatment. Clinical mastitis can be severe and challenging to fully resolve in New Zealand dairy sheep. Clinical relevance This is the first systematic study of clinical mastitis in New Zealand dairy ewes. It provides baseline information specific to New Zealand conditions for farmers, veterinarians, and other advisors to guide the management of mastitis for the relatively new dairy sheep industry in New Zealand.

The effect of selective dry cow therapies based on two different algorithms on antimicrobial use, udder health, milk production, and culling in the absence of internal teat sealant use at dry-off.

The objective of this study was to evaluate the effect of selective dry cow therapy (SDCT) strategies based on 2 different algorithms as compared with blanket dry-cow therapy for measures of udder health, milk yield, and culling in herds not using internal teat sealant. Cows from 2 commercial farms in West Texas were randomized into 3 different groups: SDCT Algorithm 1 (ALG1; n = 455) cows treated with an intramammary antimicrobial at dry-off if somatic cell count (SCC) > 200,000 cells/mL at any Dairy Herd Improvement Association (DHIA) test date or if the cow had 2 or more cases of clinical mastitis during the enrollment lactation; SDCT Algorithm 2 (ALG2; n = 458) cows treated with an intramammary antimicrobial at dry-off if SCC >200,000 cell/mL at last test date or any case of clinical mastitis during the enrollment lactation; Control cows (CON = 447) received blanket dry cow therapy. All cows enrolled in the study did not receive an internal or external teat sealant. Data related to milk and somatic cell count linear score (LSCC) was collected monthly. Milk yield and LSCC during the first 6 mo of lactation were analyzed using repeated measures ANOVA models, while Cox's Proportional Hazards models were fitted to culling and clinical mastitis data. The farm was fitted as a random effect in all models. The percentage of cows receiving antimicrobials at dry cow was 51.3, 24.7, and 100% for ALG1, ALG2, and CON, respectively. Treatment did not influence the IMI dynamics during the dry period. Additionally, no statistical differences related to treatment were observed for LSCC and milk yield. The LSCC for ALG1, ALG2, and CON was 2.44, 2.41, and 2.26, respectively. The average milk yield for ALG1, ALG2, and CON cows was 43.2, 43.2, and 44.0 kg/d, respectively. Treatment did not affect clinical mastitis incidence and culling. The cumulative incidence of clinical mastitis was 19.6%, 19.4%, and 21.4% for ALG1, ALG2, and CON cows respectively. Additionally, the cumulative risk of death or culling was 18.5%, 17.1%, and 19.5% for ALG1, ALG2, and CON cows respectively. In conclusion, SDCT strategies led to a decrease in antimicrobial drug use at dry-off, without significantly impacting the incidence of clinical mastitis, the risk of culling, LSCC and milk yield of dairy cows. However, numerical differences in LSCC and milk yield were observed between treatment groups.

Efficacy of internal and external teat sealants on cure and new infection risk in dry-off protocols for Holstein cows

Internal teat sealant products have been used alone or in combination with antibiotic dry cow treatment to prevent new IMI over the dry period in dairy cows. Conversely, knowledge about the efficacy of external teat sealants in the prevention of IMI is scarce. The objective of our study was to investigate the effect of 2 different teat sealants, one internal teat sealant and one external teat sealant, on the (1) risk of new IMI during the dry period, (2) risk of IMI cure, (3) first test day linear somatic cell score, (4) first test day milk yield, (5) incidence of farm-diagnosed clinical mastitis ≤ 30 DIM, and (6) incidence of culling ≤ 30 DIM. In a randomized clinical trial, Holstein cows (n = 1,500) from one commercial dairy were assigned to treatment and control groups. At dry off, cows in the treatment groups received an antibiotic dry cow treatment in combination with either an internal teat sealant (INT) or a single application of an external teat sealant (EXT). Control (CON) cows received the antibiotic dry cow treatment alone. Data on linear somatic cell score from the last DHI test day before dry off and the first test after calving, first test day milk yield, and the occurrence of farm-diagnosed clinical mastitis and culling ≤ 30 DIM were obtained from the farm management program. New IMI and cure of IMI during the dry period were calculated. Linear somatic cell score (mean ± SD) at first test day after calving differed among groups and was 3.2 ± 2.2 in CON, 2.8 ± 2.0 in INT, and 3.0 ± 2.1 in EXT groups. The risk of new IMI differed among groups and was 30.2% for CON cows, 18.2% for INT cows, and 22.6% for EXT cows. A Poisson regression analysis revealed that, compared with CON cows, the risks of new IMI were 40% lower for INT cows (risk ratio (RR) = 0.60, 95% CI = 0.41 to 0.88) and 25% lower for EXT cows (RR = 0.75, 95% CI = 0.52 to 1.07). By contrast, no meaningful differences were documented for cure risk, clinical mastitis risk during the first 30 DIM, or culling risk within the first 30 DIM. In summary, cows dried off with an INT in combination with antibiotic dry cow treatment had a lower linear somatic cell score at first test day after calving and reduced risk of new IMI than cows dried off with an EXT in addition to antibiotic dry cow treatment or cows dried off using antibiotic dry cow treatment alone. Further, we found supporting evidence that cows dried off with an EXT in addition to antibiotic dry cow treatment might have an advantage in reduced new IMI over cows dried off with an antibiotic dry cow treatment alone.

Balancing farm profit and greenhouse gas emissions along the dairy production chain through breeding indices

Breeding is a promising greenhouse gas (GHG) mitigation option for the dairy sector that offers potential permanent and cumulative effects. However, there is limited understanding of how genetic traits affect GHG emissions from the dairy production chain and how breeding indices could be used to find a balance between GHG emissions and farm profit. Using a typical Chinese dairy farm as a case study, we developed a novel method to address these gaps. The farm comprised of 1523 Holstein-Friesian dairy cows and 1429 young stock. The average milk yield at the farm was 11,533 kg per cow per year. Life cycle assessment was combined with an existing bio-economic model to determine the emission intensity values (IV) of six genetic traits: milk yield, protein yield, fat yield, calving interval, productive life, and incidence of clinical mastitis. The IVs and economic values of the traits were used to form different breeding indices, of which the economic and environmental consequences were assessed. Results showed that for the next generation, breeding animals with optimal indices could reduce carbon dioxide equivalents per ton of fat-and-protein-corrected milk by six to 10 kg, while increasing profitability by 822 to 1355 Chinese Yuan per cow unit. Different indices can balance farm profit and GHG emissions to different degrees. However, the indices with higher profit showed less potential in reducing GHG emissions. This study provides insights into how breeding strategies could contribute to GHG mitigation in the dairy sector.

Udder, Claw, and Reproductive Health in Genomic Selection of the Czech Holstein.

The aim of this study was to construct an enhanced selection index using the genomic and economic parameters of new health disorders and current production and functional traits. Genomic evaluation for the incidence of clinical mastitis (CM), three claw disease traits, retained placenta (RET), metritis (MET), and cystic ovaries (CYS) was performed using linear animal models based on producer-recorded data. Good correlations among the health disorders were found, and their heritability estimates did not exceed 7%. Economic weights (EWs) for the health disorders were EUR -132.10 for CM, EUR -128.87 for overall claw diseases, EUR -52.10 for RET, EUR -80.48 for MET, and EUR -16.16 for CYS. These EWs indicate changes in the present value of the annual profit per cow when increasing the incidence of the traits by one case per cow year. Selection using the enhanced index resulted in favourable responses for most of the new health disorders (e.g., -0.001 and -0.006 cases of RET and MET per cow year, respectively), and also in the current breeding objective traits (+49 kg of milk, -0.02% of calf losses). An index contribution of 7% for the new health disorders was assessed as acceptable for the breeders.

Body conformation traits in early-lactation associated with clinical mastitis and lameness in lactating Chinese holstein cows

BackgroundComprehending the correlation between body conformation traits of cows at the early stages of lactation and prevalent lactation diseases might facilitate the execution of selection and feeding strategies that prioritize cow health. This study aimed to evaluate the impact of body conformation traits on the incidence of clinical mastitis and lameness in Chinese Holstein cows. From a pasture herd of 1472 early lactating Chinese Holstein cows, we evaluated 20 body conformation traits. During lactation, this pasture herd was visited weekly to gather clinical mastitis and lameness data. A nine-point scale was used to determine the conformation traits of cows to clarify their linear characters, including frame capacity, rump (RU), feet and leg (FL), mammary system (MS), and dairy character. A longitudinal binary disease (0 = healthy; 1 = diseased) data structure was created by allocating disease records to adjacent official test dates. The impact of body conformation traits on the risk of developing diseases (clinical mastitis and lameness) was analyzed using the logistic regression models.ResultsCompared to cows with low total scores (75–79 points), those with high total scores (80–85 points) of body conformation traits had a significantly lower risk of mastitis (P < 0.001). The disease status (0 or 1: binary variable) of clinical mastitis in lactating cows was significantly impacted negatively by age (P < 0.05). The fore udder attachment (FUA), angularity, rear attachment height (RAH), and rear teat placement (RTP) were all significantly associated with clinical mastitis during lactation (P < 0.05). The rear leg-rear view (RLRV) was significantly correlated with correlated considerably (P < 0.05) with lameness during lactation. An ideal score of four points on the lameness risk dimension of the RLRV may indicate a low risk of lameness. Since the risk of mastitis decreased as this trait score increased, the RTP may be an ideal marker for mastitis risk.ConclusionsAccording to the study, clinical mastitis and lameness risks in cows can be estimated using their body conformation traits. Cows with more centrally located rear teats have a lower risk of mastitis. These results may help dairy farmers identify cows at high risk of disease early in lactation and aid in breeding for disease resistance in cows.

Evaluation of close up antimicrobial therapies for treatment and prevention of subclinical mastitis in the herds with high prevalence of Staphylococcus aureus

This field trial was conducted to evaluate two antibiotics at a close-up period in curing the existing IMI and to prevent new clinical and subclinical Intramammary infection (IMI). Two hundred and twelve Holstein cows were assigned to one of three treatment groups: TYLO, MARB and CONT. Cows in TYLO group received 10 mg/kg Tylosin for three days at the close-up period (21 days before calving), cows in MARB group received single SC injection of 8 mg/kg SC marbofloxacin at the close-up period and cows in CONT group remained untreated. Milk samples were collected for somatic cell count, microbial culture and Total oxidant/antioxidant capacity before drying-off, and 3 and 7days post calving. Antimicrobial susceptibility test and RAPT-PCR were performed on S.aureus isolates. No significant differences were detected in total cure rate within the groups, but S. aureus cure rates in TYLO and MARB were significantly higher than in CONT (74 and 73.5 % Vs 58.1 %). No significant differences in total new IMI were observed. Furthermore, the rate of new S. aureus IMI was higher in both treatment groups than in CONT group. Clinical mastitis rate in TYLO (3.8 %) and MARB (5.8 %) was significantly lower than CONT (11.3 %). Paired S. aureus isolates from dry-off and post-calving have been clustered into 9 different RAPD types (A-I). 8 paired strains collected at dry-off were identical to those at post-calving,and 35 strains had more than 60 % dissimilarity. Administration of Tylosin or Marbofloxacin is not useful in all cases;however, they have the potential to reduce the incidence of post-calving clinical mastitis and improve S.aureus cure rate if used selectively.

Evaluation of internal teat sealant persistence in the mammary gland during the dry period

The aim of this study was to characterize the behavior of 2 commercially available internal teat sealants containing bismuth subnitrate (SOa and ORBb) during the dry- and postfresh periods in dairy cattle. Digital radiography was used to monitor location and percentage of teat cistern fill at dry-off and during the dry period. Teat-level health parameters including infection status at dry-off and post-fresh as well as incidence of clinical mastitis were also assessed. Radiographic imaging revealed that 21.1% of teats had sealant present in the gland cistern at dry-off (SO= 23.6%, ORB = 18.5%) which increased to 55.9% (SO = 59.6%, ORB = 52.2%) at pre-fresh imaging. Quarters with sealant that had migrated into the gland shed noticeable amounts of sealant for twice as long (mean 14.34 milkings), compared to quarters that did not have sealant in the gland (mean: 7.12, P &lt; 0.001). There was no correlation between sealant location and intramammary infection at dry-off or post-fresh, nor did sea ant location impact clinical mastitis in the first 120 days in milk. Milk leakage after dry-off also was not correlated with an increased risk of intramammary infection during the dry or post-fresh periods. There was no difference between treatments in any of the parameters evaluated. Prolonged sealant shedding is a common reason that producers cite for not utilizing internal teat sealant products in their dry-off protocols. Further research is indicated to determine the optimal amount of sealant required to provide protection while minimizing post-fresh shedding.

Randomized equivalence study evaluating the efficacy of two commercially available teat sealants in dairy cows

Use of internal teat sealants is common in the U.S. to prevent new intramammary infections during the dry period. The objective of this study was to compare the efficacy of a new internal teat sealant containing bismuth subnitrate (SOa) to the first product introduced to the U.S. dairy industry (ORBb). The hypothesis was completed using a multi-site randomized, positively controlled equivalence evaluation of new intramammary infection risk difference over the dry period. At dry-off, milk samples were collected for culture and then cloxacillin benzathinec was administered, followed by the randomly assigned internal teat sealant (SO = 404 cows; ORB = 418 cows). After calving, repeat milk samples were collected. The effect of treatment on quarter-level new intramammary infection risk, cured intramammary infection risk, and risk of presence of intramammary infection post-calving was determined using generalized linear mixed models. The effects of treatment on cow-level outcomes, including incidence of clinical mastitis, culling and death, and performance in early lactation based on test-day milk production and somatic cell count, were also evaluated. The dry period new intramammary infection adjusted risk difference (SO minus ORB) was -1.60% (95% CI -5.62, 2.42). Final models demonstrated that there was no difference in risk rates of quarter-level outcomes between treatment groups. Analysis of cow-level factors, including clinical mastitis, culling and death rate within the first 120 DIM, also revealed no differences. Results of this study indicate that SO was equivalent to ORB for dry period new intramammary infection risk when utilizing blanket dry cow therapy.

Evaluation of the Role of Veterinarians for Outcomes Related to the Health and Production of Dairy Small Ruminants in Greece

The objective of the present study was to evaluate the potential benefits of veterinarians in improving the health and welfare of dairy sheep and goats by studying the associations of management practices employed in the farms with production- or health-related outcomes in sheep and goat farms in Greece. This work explored associations with ‘professional relationship with a veterinarian’ at 444 small ruminant dairy farms in an investigation performed around Greece, where 106 variables, related to infrastructure, animals, production outcomes, health management, health problems and human resources, were assessed. In 384 (86.5%) farms, a professional relationship with a veterinarian was maintained. The median value of visits made annually by veterinarians to these farms was five. In farms with a professional relationship with a veterinarian, significant differences were found in 24 variables (35.8%) related to management practices and 6 (30.0%) production- or health-related outcomes. In multivariable analysis, the following emerged with a significant association: epg counts in faecal samples (p = 0.014), average annual milk production per ewe/doe (p = 0.015), somatic cell counts in bulk-tank milk (p = 0.037), and annual incidence of clinical mastitis (p = 0.044). Moreover, associations of the characteristics of veterinarians emerged with somatic cell counts in bulk-tank milk: the gender (p &lt; 0.0001) and the age (p = 0.004) of the veterinarians. The results attest that the application of veterinary advice and clinical services in sheep and goat dairy farms contributes to the improved health, production and welfare of animals.

Impact of temporal variations and risk factors associated with udder inflammation in Hardhenu cattle (Bos taurus × Bos indicus).

This study aimed to explore the occurrence and risk factors associated with clinical mastitis within the Hardhenu cattle herd over a span of 14 years (2008-2021). A comprehensive analysis of 1515 lactation records was conducted to ascertain the incidence of clinical mastitis. The investigation determined an overall incidence rate of 26.80% in the studied population. A significant relationship between the year and clinical mastitis incidence was established through Chi-square analysis (p < .05). Temporal variations in clinical mastitis odds were apparent, with the highest odds (ranging from 0.91 to 1.00) observed during the initial years of 2008-2009 and 2009-2010. Logistic regression revealed that odds values for clinical mastitis incidence were highest in 2008-2009 (1.00), succeeded by 2009-2010 (0.91), 2012-2013 (0.88), 2018-2019 (0.67) and reaching the lowest in 2021-2022 (0.35). Subsequent rankings included 2010-2011 (0.39), 2014-2015 (0.43) and 2019-2020 (0.45). Parity was found to be significantly associated with clinical mastitis occurrence. When compared to Parity 3, both Parity 1 (odds ratio: 1.516, 95% confidence interval: 0.881-2.612) and Parity 2 (odds ratio: 2.626, 95% confidence interval: 1.568-4.398) exhibited higher odds values for clinical mastitis incidence. While the period of calving did not exert a significant influence on clinical mastitis incidence, a heightened occurrence was observed during the rainy season within the targeted population. These findings offer valuable insights into the patterns of incidence, temporal fluctuations, and non-genetic determinants impacting clinical mastitis within the Hardhenu cattle. The implications of this study can facilitate the development of targeted strategies and management protocols aimed at enhancing udder health and overall productivity in dairy cattle.

Recovery of Staphylococci from Teatcups in Milking Parlours in Goat Herds in Greece: Prevalence, Identification, Biofilm Formation, Patterns of Antibiotic Susceptibility, Predictors for Isolation.

The objectives of this work are (a) to describe staphylococci on the teatcups of milking parlours in goat farms and identify predictors for the presence of staphylococcal isolates on the teatcups, (b) to evaluate relationships with total bacterial counts and somatic cell counts in bulk-tank milk, and (c) to establish patterns of susceptibility to antibiotics for the staphylococcal isolates and identify predictors for the recovery of resistant isolates. In a cross-sectional study of 66 goat farms across Greece, swab samples were collected from 303 teatcups (upper and lower part) for staphylococcal recovery, identification, and assessment of biofilm formation. Details regarding health management on the farms (including conditions in the milking parlour) and the socio-demographic characteristics of farmers were collected by means of a structured questionnaire. A total of 87 contaminated teatcups (28.7%) were found on 35 goat farms (53.0%). Staphylococci were more frequently recovered from the upper than the lower part of teatcups: 73 versus 43 teatcups, respectively. After identification, 67 staphylococcal isolates (i.e., excluding similar isolates) were recovered from the teatcups; Staphylococcus aureus, Staphylococcus capitis, and Staphylococcus equorum predominated. Of these isolates, 82.1% were biofilm-forming. In multivariable analysis, the annual incidence of clinical mastitis in the herd emerged as the only significant factor associated with the isolation of staphylococci from the teatcups. Of the 67 isolates, 23 (34.3%) were resistant to at least one antibiotic, and 14 (22.4%) were multi-resistant. Resistance was found most commonly against penicillin and ampicillin (22.4% of isolates), fosfomycin (17.9%), clindamycin (14.9%), erythromycin, and tetracycline (13.4%). In multivariable analysis, the annual incidence of clinical mastitis in the herd and the use of detergent for parlour cleaning emerged as significant factors associated with the isolation of staphylococci resistant to antibiotics.

Characterization of internal teat sealant behavior throughout the dry and post-fresh periods

The primary objective of this study was to characterize the be­havior of internal teat sealants during the dry period as well as sealant shedding patterns during the post-fresh period in dairy cattle. Two commercially available teat sealants were utilized for this study ShutOutTM (Merck Animal Health, Madison, NJ) versus Orbeseal® (Zoetis, Parsippany, NJ). Digital radiography was used to monitor location and percentage of teat fill with sealant at dry off during the dry period. Other parameters eval­uated included weight of sealant shed at first milking, duration of sealant shedding after freshening, and amount of sealant shed at each milking. Incidence of clinical mastitis, teat-level infection status at dry off, and teat-level infection status during the dry and post-fresh periods were also assessed.

A randomized non-inferiority study evaluating the efficacy of two commercially available teat sealants in dairy cows

The primary objective of this study was to compare the effi­cacy of a new internal teat sealant (ShutOutTM, Merck Animal Health, Madison, NJ) (SO) to the current U.S. industry leader (Orbeseal®, Zoetis, Parsippany, NJ) (ORB). This comparison was based on a non-inferiority evaluation of quarter-level new in­fection risk during the dry period, with secondary comparisons of cure risk, incidence of clinical mastitis at the cow level dur­ing the first 120 days in milk, as well as cow-level performance in early lactation based on milk production, somatic cell count (SCC), and risk for removal from the herd.

Single nucleotide polymorphism, haplotypes and genotypes of Mannose-binding lectin (MBL1) gene and their association with clinical mastitis in Murrah buffalo

The Mannose-binding lectin (MBL1) gene is an important component of immune response system. It plays vital role in activation of the complement system and act as chief defense molecule of host cell to provide protection against various diseases. In the recent study, six novel single nucleotide polymorphisms (SNPs), at 2689G&gt;C, 2751A&gt;G, 4822T&gt;C, 4853A&gt;G, 4855T&gt;C, and 4978T&gt;C resulted in 2 non synonymous type of change at 4853A&gt;G, 4855T&gt;C resulting in one amino acid substitution Ser150Gly of MBL1 protein and their association with clinical mastitis were investigated in two hundred (200) Murrah buffaloes. These SNPs in MBL1 were genotyped by using the polymerase chain reaction (PCR) and Deoxyribose nucleic acid (DNA) sequencing methods in order to reveal the association with clinical mastitis. SHEsis software tool was used for construction of haplotypes and Linkage disequilibrium analysis. Twenty one (21) haplotypes were constructed. Allelic association analysis showed that C allele of 2689 G&gt;C, A allele of 2751 A&gt;G, C allele of 4822 T&gt;C, A allele of 4853 A&gt;G, C allele of 4855 T&gt;C, and C allele of 4978 T&gt;C had significant association with increased risk of clinical mastitis in Murrah buffaloes (P&lt;0.05). Murrah buffaloes with CG genotype of 2689 G&gt;C, AG or GG genotype of 2751 A&gt;G, CC genotype of 4822T&gt;C, AG or GG genotype of 4853 A&gt;G, TC or CC genotype of 4855 T&gt;C and CC genotype of 4978 T&gt;C loci had significantly lower incidence of clinical mastitis compared to their counter genotypes. Haplotype association analysis showed that Hap21 (TATTGA) was found significantly related to higher risk of clinical mastitis (P&lt;0.05). Hap14 (TGTTGG) and Hap5 (CGCCCA) were found significantly associated with lower risk of clinical mastitis in Murrah buffalo (P&lt;0.05).

Effect of feeding a Saccharomyces cerevisiae fermentation product to Holstein cows exposed to high temperature and humidity conditions on milk production performance and efficiency—A pen-level trial

The objective of this study was to evaluate the effect of feeding a Saccharomyces cerevisiae fermentation product (SCFP) on milk production efficiency of Holstein cows naturally exposed to high temperature and humidity conditions. The study was conducted in 2 commercial farms in Mexico from July to October 2020 and included 1 wk covariate period, 3 wk adaptation, and 12 wk data collection. Cows [n = 1,843; ≥21 d in milk (DIM) and <100 d carried calf] were enrolled and assigned to the study pens (n = 10) balanced for parity, milk yield, and DIM. Pens were fed a total mixed ration diet either without (CTRL) or with SCFP (19 g/d, NutriTek, Diamond V). Milk yield, energy-corrected milk (ECM), milk components, linear somatic cell score, dry matter intake (DMI), feed efficiency (FE; Milk/DMI and ECM/DMI), body condition score, and the incidence of clinical mastitis, pneumonia, and culling were monitored. Statistical analyses included mixed linear and logistic models accounting for repeated measures (when applicable; multiple measurements per cow within treated pens) with pen as the experimental unit and treatment, time (week of study), parity (1 vs. 2+), and their interactions as fixed and pen nested within farm and treatment as random effect. Parity 2+ cows within pens fed SCFP produced more milk than cows within CTRL pens (42.1 vs. 41.2 kg/d); there were no production differences between groups of primiparous groups. Cows within SCFP pens had lower DMI (25.2 vs. 26.0 kg/d) and greater FE (1.59 vs. 1.53) and ECM FE (1.73 vs. 1.68) than cows within CTRL pens. Milk components, linear somatic cell score, health events, and culling were not different between groups. At the end of the study (245 ± 54 DIM), SCFP cows had greater body condition score than CTRL (3.33 vs. 3.23 in the first parity; 3.11 vs. 3.04 in 2+ parity cows). Feeding Saccharomyces cerevisiae fermentation products to lactating cows exposed to high temperature and humidity conditions improved FE.

Causal association of epidemiological factors with the incidence of bovine clinical and subclinical mastitis

Causal association of epidemiological factors with the incidence of bovine clinical and subclinical mastitis

Genetic variation in promoter region of the bovine LAP3 gene associated with estimated breeding values of milk production traits and clinical mastitis in dairy cattle.

The purpose of this study was to identify genetic variants in the promoter and 5'UTR regions of bovine leucine amino peptidase three (LAP3) gene and analysed their associations with estimated breeding values (EBVs) of milk production traits and clinical mastitis in Sahiwal and Karan Fries cattle. Eleven SNPs were identified within the region under study of the LAP3 gene, including seven promoter variants (rs717156555: C>G, rs720373055: T>C, rs715189731: A>G, rs516876447: A>G, rs461857269: C>T, rs136548163: C>T, and rs720349928: G>A) and four 5'UTR variants (rs717884982: C>T, rs722359733: C>T, rs481631804: C>T and rs462932574: T>G). Out of them, 10 SNPs variants were found in both Sahiwal and Karan Fries cattle, with one SNP variant (rs481631804: C>T) being unique to Karan Fries cattle. Seven of these identified SNPs were chosen for association analyses. Individual SNP based association analysis revealed that two SNPs (rs720373055: T>C and rs720349928: G>A) were significantly associated with EBVs of lactation milk yield (LMY), 305-day milk yield (305dMY), and one significant association of SNP rs722359733: C>T with lactation length (LL) was observed. Haplotype based association analysis indicated that diplotypes are significantly associated with EBVs of LMY, 305dMY, and LL, individuals with H1H3 (CTACGCT/GCGTACG) being linked to higher lactation performance than other diplotypes. Further logistic regression analysis revealed that, animals with diplotype H1H3 was less susceptible to the incidence of clinical mastitis than other cows, as the odds ratio for the non-incidence of clinical mastitis was found to be low. Altogether, variations in the LAP3 gene promoter could be used as a genetic marker, most notably diplotype H1H3, may greatly benefit the simultaneous improvement of mastitis resistance and milk yield traits in dairy cattle. Moreover, bioinformatics analysis predicted that the SNPs rs720373055: T>C, rs715189731:A>G and rs720349928: G>A is located in the core promoter region and in TFBs, play key role in regulation of studied phenotypes.

Status of udder health performance indicators and implementation of on farm monitoring on German dairy cow farms: results from a large scale cross-sectional study.

Regional benchmarking data enables farmers to compare their animal health situation to that of other herds and identify areas with improvement potential. For the udder health status of German dairy cow farms, such data were incomplete. Therefore, the aim of this study was (1) to describe the incidence of clinical mastitis (CM), (2) to describe cell count based udder health indicators [annual mean test day average of the proportion of animals without indication of mastitis (aWIM), new infection risk during lactation (aNIR), and proportion of cows with low chance of cure (aLCC); heifer mastitis rate (HM)] and their seasonal variation, and (3) to evaluate the level of implementation of selected measures of mastitis monitoring. Herds in three German regions (North: n = 253; East: n = 252, South: n = 260) with different production conditions were visited. Data on CM incidence and measures of mastitis monitoring were collected via structured questionnaire-based interviews. Additionally, dairy herd improvement (DHI) test day data from the 365 days preceding the interview were obtained. The median (Q0.1, Q0.9) farmer reported incidence of mild CM was 14.8% (3.5, 30.8%) in North, 16.2% (1.9, 50.4%) in East, and 11.8% (0.0, 30.7%) in South. For severe CM the reported incidence was 4.0% (0.0, 12.2%), 2.0% (0.0, 10.8%), and 2.6% (0.0, 11.0%) for North, East, and South, respectively. The median aWIM was 60.7% (53.4, 68.1%), 59.0% (49.7, 65.4%), and 60.2% (51.5, 67.8%), whereas the median aNIR was 17.1% (13.6, 21.6%), 19.9% (16.2, 24.9%), and 18.3% (14.4, 22.0%) in North, East, and South, respectively with large seasonal variations. Median aLCC was ≤1.1% (≤ 0.7%, ≤ 1.8%) in all regions and HM was 28.4% (19.7, 37.2%), 35.7% (26.7, 44.2%), and 23.5% (13.1, 35.9%), in North, East and South, respectively. Participation in a DHI testing program (N: 95.7%, E: 98.8%, S: 89.2%) and premilking (N: 91.1%, E: 93.7%, S: 90.2%) were widely used. Several aspects of udder health monitoring, including exact documentation of CM cases, regular microbiological analysis of milk samples and the use of a veterinary herd health consultancy service were not applied on many farms. The results of this study can be used by dairy farmers and their advisors as benchmarks for the assessment of the udder health situation in their herds.

The effects of novel electrical teat dipping on some mastitis parameters in dairy herds.

Electrical teat dipping (ETD) is a novel, patented method developed by the authors to control mastitis in dairy cows. Here we evaluate the efficacy of ETD in reducing the incidence of clinical mastitis and bulk tank milk somatic cell count (BTMSCC) on three dairy farms over 6 months. ETD was applied for morning and evening milking on three farms, while conventional teat dipping (CTD) was applied on the other three farms. The number of animals and quarters with clinical mastitis and monthly BTMSCC measurements were recorded. We found that the incidence of clinical mastitis was lower on farms using ETD than those using CTD. However, the BTMSCC did not significantly change throughout the study. Based on these findings, we conclude that ETD effectively reduces mastitis rates on dairy farms.