The prevalence of subclinical mastitis in dairy goats in Kenya

California mastitis test (CMT), direct leukocytes counts and bacteriological examination were performed on 630 milk samples from apparently healthy mammary glands of dairy goats comprising a mixed population of German Alpine, Toggenberg, Saanen and Galla crosses to find the prevalence of subclinical mastitis. The prevalence of subclinical mastitis was 9.8% according to CMT, 9.7% according to direct leukocyte counts and 28.7% by bacterial isolation during a 3-month period. The proportion of the bacteriologically positive milk samples was significantly (P <0.01) higher than that positive for CMT and direct leukocyte counts. There was a significant (P < 0.01) correlation between CMT and direct leukocyte counts. There was no significant direct relationship between bacterial isolation and CMT Bacterial organisms were isolated in 22.5% of the 568 CMT-negative milk samples. The results suggest that bacterial organisms isolated from the CMT-negative milksamples were either latent infections or did not stimulate any significant increase in somatic cell counts that could be detected by either the CMT or direct leukocyte counts. The observations of this study indicate that the mere presence of bacteria in goat's milk does not mean that the udder is infected and so does not warrant antibiotic therapy.     

Prevalence, risk factors, and major bacterial causes of camel mastitis in Borana Zone, Oromia Regional State, Ethiopia

A cross-sectional study was carried out from November 2010 up to April 2011 to estimate mastitis prevalence and associated risk factors and to assess its bacterial causes in traditionally managed camels in Borana Zone, Southern Ethiopia. Thus, 348 lactating camels were examined clinically, and subclinical cases were checked with California mastitis test (CMT). The overall prevalence of mastitis was 44.8 % (156/348), comprising clinical (19, 5.4 %) and subclinical (137, 39.4 %) cases. The quarter level prevalence of mastitis was 24.0 % (334/1,392). Of the total 1,392 examined teats, 30 were blind, and hence, from the 1,362 non-blind CMT-examined teats, 22.3 % (304/1,362) were CMT positive. Of the 304 CMT-positive samples, 264 were culture positive (197 Gram-positive, 41 Gram-negative, and 26 mixed isolates), and 40 were culture negative. The prevalence of Staphylococcus aureus was found to be the highest at both the animal (12.8 %, 39/304) and quarter level (2.9 %, 39/1,362). Regression analysis revealed higher likelihood of mastitis occurrence among camels from Dharito (OR?=?3.4, 95 % confidence interval (CI)?=?1.8, 6.4), Gagna (OR?=?3.4, 95 % CI?=?1.8, 6.5), and Haro Bake (OR?=?2.6, 95 % CI?=?1.3, 5.1) than camels from Surupha. Likewise, there was higher chance of mastitis occurrence among camels at the early lactation stage (OR?=?2.3, 95 % CI?=?1.1, 4.6) and camels with udder/teat lesions (OR?=?13.7, 95 % CI?=?1.7, 109.4) than among camels at late lactation stage and camels with healthy udder/teats, respectively. In conclusion, this study reveals the current status of camel mastitis in Southern Ethiopia.     

Relationship between teat morphological traits and subclinical mastitis in Frieswal dairy cows

The present study was aimed to investigate the relationship between selected morphological traits of teat and subclinical mastitis (SCM) in Frieswal crossbred dairy cows. A total of 1040 quarters from 261 lactating cows were evaluated for teat shape (bottle/fleshy/collapsed/conical/normal/pencil and short), teat-end shape (dished/flat/funnel/pocketed/pointed and rounded), teat orientation (aligned/misaligned) and teat position (front and rear; left-sided and right-sided). Each udder quarter was screened with California Mastitis Test (CMT) for the purpose of defining quarter health status. Data were analysed using Chi-square test and multivariable logistic regression procedure. An overall prevalence of SCM (CMT positive) at quarter level was 30.6%. Most of the teats had normal or cylindrical shapes (48%), dished teat-ends (40.7%), and aligned (central or squared) in orientation (65%). At bivariable level, significant association of SCM with teat shape, teat position, teat orientation, parity, and stage of lactation was observed (P < 0.05 to P < 0.001). Teat-end shapes showed some association with SCM (P = 0.07). Results of multivariable analysis showed that pencil-shaped teats were least associated with SCM (P < 0.05) as compared to other teat shapes. Prevalence of SCM was also higher in rear teats (P = 0.015), misaligned teats (P = 0.01), and cows in second or higher parities (P < 0.01) and late stage of lactation (P < 0.001). The results of the present study indicate that selected morphological traits of teat are associated with SCM in Frieswal crossbred cows; therefore, selection towards desirable morphological traits could help reduce mastitis in this breed.     

Clinical and ultrasonographic findings in the mammary gland of sheep

AIM: To compare clinical and ultrasonographic findings and assess the value of ultrasonography for evaluating the structure and condition of the teat and teat canal of sheep. METHODS: The mammary glands of 30 lactating ewes were examined clinically and using ultrasonography. The distance from the teat tip to the ground was measured and diagnostic images of the body of the gland, gland cistern and teat cistern were obtained using an 8.5 MHz frequency ultrasonic transducer. A California mastitis test (CMT) and bacteriological culture were performed on milk samples collected from each half of each udder. RESULTS: Udder parenchyma and teats were palpably normal in 27/30 (90%) ewes. Milk clots or abnormalities were evident in 4/30 (13%) udders, lesions in the glandular parenchyma and/or teats were evident by palpation in 3/30 (10%), and pathogenic bacteria were cultured from 2/30 (7%). In both of the latter cases, mastitis was diagnosed based on clotted and discoloured appearance of milk and highly positive CMT reactions. Ultrasonographic examination in these udders revealed non-homogenous regions in the glandular tissue and alternating areas of hyperechogenic and hypoechogenic tissue. Overall, highly positive CMT reactions were evident in milk from 14/30 (47%) left halves and 9/30 (30%) right halves (p=0.02). No relationship between teat-to-ground distances and CMT results was evident (p>0.05). Teat canal lengths ranged from 5.7-10.3 mm (mean=8.6; SD=1.3 mm) and the widths from 1.8-3.1 mm (mean=2.3; SD=0.4 mm). Milk sampled from ewes that had long (> or = 9 mm) or wide (> or = 2 mm) teat canals was highly positive to the CMT in 75% and 83% of cases, respectively. CONCLUSIONS: Ultrasonographic measurements of the length and width of the teat canal appeared to correlate with CMT results. The use of ultrasonography in evaluating the health of the udder of small ruminants holds promise for the future.     

Relationship between California Mastitis Test score and ultrasonographic teat measurements in dairy cows

Objective The majority of published studies about mastitis are related to the control and prevention of mastitis, with particular emphasis on eliminating predisposition factors. The objective of the current study was to determine the role of teat morphology as an important factor in the aetiology of mastitis. Design Ultrasonographic measurements were taken from 190 teats from 100 dairy cows of different breeds. Procedure Mastitis in cows was diagnosed by the California Mastitis Test (CMT) and microbiological tests. The data were evaluated in the light of the clinical history of the animals. Results Main effects of breed on teat diameter at the position of the Furstenberg rosette (FTD) and teat cistern diameter (CD), that of age on FTD and overall teat diameter (OTD), and that of CMT score on CD and OTD were significant (P < 0.05, P < 0.01). Number of lactations, pregnancy, the lactation period and the udder lobe (rear, front) were not found to have a significant effect on any of the measurements. Results showed that CD was significantly smaller (1.44 ± 0.04 cm) (P < 0.01) in CMT‐positive udder lobes than that in CMT‐negative lobes. No difference was detected in canal length, CD, teat wall thickness, OTD or FTD between the CMT‐positive and ‐negative lobes. Conclusion The occurrence of mastitis could be related to specific ultrasonographic teat measurements (e.g. CD, OTD and FTD) and these may be important in the breeding of cows with a predisposition to mastitis, as well in the evaluation of in‐herd cows in terms of udder/teat deformities.     

Fungi isolated from bovine udders , and their possible sources

AIM: To identify fungi isolated from infections of the bovine mammary gland, and establish their possible sources. METHODS: From a herd of 420 cows, milk samples were collected from all quarters at calving and cultured to detect causative organisms. Quarters identified as infected with fungi were further sampled during early lactation. Samples from feedstuffs, the feed pad and ends of teats were also collected and analysed for the presence of fungi. RESULTS: Eleven of 420 cows were diagnosed with intramammary infections (IMI) caused by yeasts (nine cows, 10 quarters) and moulds (two cows, three quarters). Six of the yeast species had previously been reported as being responsible for mastitis. Elevated somatic cell counts (SCC) were observed in many quarters, but most infections were eliminated spontaneously. Two of the fungi isolated from milk samples were also isolated from feedstuffs and teat swabs, and seven other fungi isolated from milk samples were not isolated from feed, the feed pad or cows' teats. CONCLUSIONS: Isolation of fungi from the udder is rarely reported in dairy cows in New Zealand. In this herd, contamination of the end of the teat originating from feedstuffs and possibly exacerbated by the use of a feed pad may have led to the establishment of IMI caused by fungi. CLINICAL RELEVENCE: Fungi are infrequently if ever reported in mastitis trial data or surveys in New Zealand and are probably of little clinical significance. KEY WORDS: Fungi, yeast, mould, bovine, intramammary infection, somatic cell count, mastitis.     

Clinical and subclinical mastitis in smallholder dairy farms in Tanzania: risk, intervention and knowledge transfer

In a cross-sectional study of 400 randomly selected smallholder dairy farms in the Tanga and Iringa regions of Tanzania, 14.2% (95% confidence interval (CI)=11.6-17.3) of cows had developed clinical mastitis during the previous year. The point prevalence of subclinical mastitis, defined as a quarter positive by the California Mastitis Test (CMT) or by bacteriological culture, was 46.2% (95% CI=43.6-48.8) and 24.3% (95% CI=22.2-26.6), respectively. In a longitudinal disease study in Iringa, the incidence of clinical mastitis was 31.7 cases per 100 cow-years. A randomised intervention trial indicated that intramammary antibiotics significantly reduced the proportion of bacteriologically positive quarters in the short-term (14 days post-infusion) but teat dipping had no detectable effect on bacteriological infection and CMT positive quarters. Other risk and protective factors were identified from both the cross-sectional and longitudinal included animals with Boran breeding (odds ratio (OR)=3.40, 95% CI=1.00-11.57, P<0.05 for clinical mastitis, and OR=3.51, 95% CI=1.29-9.55, P<0.01 for a CMT positive quarter), while the practice of residual calf suckling was protective for a bacteriologically positive quarter (OR=0.63, 95% CI=0.48-0.81, P相似文献   

Culture-independent exploration of the teat apex microbiota of dairy cows reveals a wide bacterial species diversity

Due to their close proximity to the mammary gland tissue, the bacterial communities lining the teat apex of the udders from lactating cows influence udder health. Denaturing gradient gel electrophoresis of the amplified V3 variable region of the 16S rRNA gene was used as a culture-independent method to reveal the bacterial composition of 48 samples originating from the teat apices of twelve Friesian-Holstein dairy cows suffering from clinical mastitis in one quarter. The microbiota belonged to four bacterial phyla: the Actinobacteria (32% of all genera), the Bacteroidetes (1%), the Firmicutes (42%), and the Proteobacteria (25%), encompassing 17 bacterial genera. Some differences in occurrence of these genera were seen when comparing quarters that were non-infected (n=22), subclinically infected (n=14), or clinically infected (n=12). Besides commensal skin-associated bacteria, opportunistic pathogenic bacteria, and mastitis-causing pathogens were found as well. The species diversity varied considerably among the most prevalent bacterial genera. While Corynebacterium and Staphylococcus displayed a large diversity among the recovered sequences, indicating the possible presence of a variety of different species, only a single bacterial species (represented by one sequence) was obtained for the genera Aerococcus, Acinetobacter, and Psychrobacter. In conclusion, introducing culture-independent analysis of teat apical skin swabs in mastitis research revealed an unexpected wide bacterial diversity, with variations between quarters with a different clinical status. In addition to potential mastitis-causing pathogens, it exposed the yet poorly mapped presence of skin-associated and other bacteria residing in close proximity to the mammary gland tissue. PCR-DGGE may thus be considered as a useful tool for the entanglement of animal skin microbiota, in casu the teat apices of dairy cows.     

Persistent Experimental Salmonella dublin Intramammary Infection in Dairy Cows

Experimental intramammary infections were induced in five post-parturient Holstein cows by inoculation of low numbers (5000 colony forming units) of virulent Salmonella dublin via the teat canal of mammary gland quarters. Rectal temperature, pulse and respiratory rates, milk yield, and milk quality as assessed by the California Mastitis Test (CMT) and somatic cell counts (SCC) were recorded every 12 hours at milking. Bacteriologic cultures of foremilk quarter samples and feces were obtained daily, as were complete blood counts. ELISA titers for IgG and IgM recognizing S. dublin lipopolysaccharide (LPS) were obtained weekly on serum and quarter milk samples. All cows excreted S. dublin intermittently from infected quarters, but no changes were detected in rectal temperature, appearance of the mammary gland or secretions, CBC, milk yield, and pulse and respiratory rates. Somatic cell counts were modestly increased in infected quarters as compared with uninfected quarters (P = .015, paired t test); however, CMT scores after infection remained low, and were not significantly different from pre-infection scores (P greater than .10, sign test). After infection, administration of dexamethasone resulted in signs of clinical mastitis and increased excretion of S. dublin from mammary quarters (P = .0004, paired t test). One cow had necrotizing mastitis and S. dublin septicemia and was euthanatized. In the four surviving cows, clinical improvement was observed after systemic gentamicin therapy and intramammary infusion with polymyxin B, but all cows continued to excrete S. dublin intermittently from one or more quarters and occasionally from feces for the remaining period of observation. All infected cows demonstrated a rise in IgG and IgM ELISA titers recognizing S. dublin LPS in serum and milk. At necropsy (13-25 weeks postinfection), S. dublin was recovered only from the mammary tissue or supramammary lymph nodes in three of four cows. In one cow, mammary gland and lymph-node samples were negative for S. dublin despite positive milk cultures. In all cows, histopathologic examination revealed multifocal areas of chronic active mastitis. These lesions were similar to histopathologic findings from mammary gland carriers with naturally acquired S. dublin infection.     

Clinical and ultrasonographic findings in the mammary gland of sheep

AIM: To compare clinical and ultrasonographic findings and assess the value of ultrasonography for evaluating the structure and condition of the teat and teat canal of sheep.

METHODS: The mammary glands of 30 lactating ewes were examined clinically and using ultrasonography. The distance from the teat tip to the ground was measured and diagnostic images of the body of the gland, gland cistern and teat cistern were obtained using an 8.5 MHz frequency ultrasonic transducer. A California mastitis test (CMT) and bacteriological culture were performed on milk samples collected from each half of each udder.

RESULTS: Udder parenchyma and teats were palpably normal in 27/30 (90%) ewes. Milk clots or abnormalities were evident in 4/30 (13%) udders, lesions in the glandular parenchyma and/or teats were evident by palpation in 3/30 (10%), and pathogenic bacteria were cultured from 2/30 (7%). In both of the latter cases, mastitis was diagnosed based on clotted and discoloured appearance of milk and highly positive CMT reactions. Ultrasonographic examination in these udders revealed non-homogenous regions in the glandular tissue and alternating areas of hyperechogenic and hypoechogenic tissue. Overall, highly positive CMT reactions were evident in milk from 14/30 (47%) left halves and 9/30 (30%) right halves (p=0.02). No relationship between teat-to-ground distances and CMT results was evident (p>0.05). Teat canal lengths ranged from 5.7–10.3 mm (mean=8.6; SD=1.3 mm) and the widths from 1.8–3.1 mm (mean=2.3; SD=0.4 mm). Milk sampled from ewes that had long (≥9 mm) or wide (≥2 mm) teat canals was highly positive to the CMT in 75% and 83% of cases, respectively.

CONCLUSIONS: Ultrasonographic measurements of the length and width of the teat canal appeared to correlate with CMT results. The use of ultrasonography in evaluating the health of the udder of small ruminants holds promise for the future.     

Fungi isolated from bovine udders,and their possible sources

AIM: To identify fungi isolated from infections of the bovine mammary gland, and establish their possible sources.

METHODS: From a herd of 420 cows, milk samples were collected from all quarters at calving and cultured to detect causative organisms. Quarters identified as infected with fungi were further sampled during early lactation. Samples from feedstuffs, the feed pad and ends of teats were also collected and analysed for the presence of fungi.

RESULTS: Eleven of 420 cows were diagnosed with intramammary infections (IMI) caused by yeasts (nine cows, 10 quarters) and moulds (two cows, three quarters). Six of the yeast species had previously been reported as being responsible for mastitis. Elevated somatic cell counts (SCC) were observed in many quarters, but most infections were eliminated spontaneously. Two of the fungi isolated from milk samples were also isolated from feedstuffs and teat swabs, and seven other fungi isolated from milk samples were not isolated from feed, the feed pad or cows' teats.

CONCLUSIONS: Isolation of fungi from the udder is rarely reported in dairy cows in New Zealand. In this herd, contamination of the end of the teat originating from feedstuffs and possibly exacerbated by the use of a feed pad may have led to the establishment of IMI caused by fungi.

CLINICAL RELEVENCE: Fungi are infrequently if ever reported in mastitis trial data or surveys in New Zealand and are probably of little clinical significance.     

Study on risk factors and their association with subclinical mastitis in lactating dairy cows in Trinidad

A cross-sectional study was conducted on dairy farms in eight milking centres in Trinidad to determine the prevalence of risk factors for mastitis and to assess their relationship to occurrence of subclinical mastitis. The California mastitis test (CMT) was used to determine the prevalence of subclinical mastitis by estimating the somatic cell counts in bulk and composite milk. Of a total of 177 dairy farms studied, 121 (68.4%), 39 (22.0%) and 17 (9.6%) practised semi-intensive, extensive and intensive management systems, respectively. A total of 129 (72.9%), 37 (20.9%) and 11 (6.2%) farms milked cows in parlours, stanchions and pasture/out-on-field, respectively. Based on sanitary practices, 40 (22.6%), 123 (69.5%), and 14 (7.9%) farms were classified as good, fair, and poor, respectively, while 76 (42.9%) and 60 (33.9%) farms reported to rarely experience and frequently experience water shortages, respectively. Amongst the 177 farms, only seven (4.0%) used machine-milking primarily, 152 (85.9%) screened for mastitis as a routine, 18 (10.2%) teat dipped, and 49 (27.7%) practised dry cow therapy. To detect mastitis, of 152 farms involved, 20 (13.2%) used the strip cup while only two (1.3%) employed the CMT. Pipe-borne water delivered directly from the hose was the only source of water to 91 (51.4%) farms while seven (4.0%) and eight (4.5%) farms used only well and surface water (ponds and rivers), respectively. Based on bulk milk samples, the farm prevalence of subclinical mastitis was 60.5% (107 of 177) with a range from 33.3% (centre 5H) to 100.0% (centre 2B). The difference was statistically significant (P < 0.01; chi 2). However, using composite milk, the farm prevalence of subclinical mastitis was 52.5% (93 of 177) with a range from 21.2% (centre 5H) to 92.9% (centre 2B) and again, the difference in prevalence was statistically significant (P < 0.001; chi 2). Subclinical mastitis was detected in 150 (45.0%) of 333 lactating cows screened and the range of prevalence was from 17.9% (centre 5H) to 56.3% (centre 1C). The difference was statistically significant (P < 0.001; chi 2). Of a total of 14 risk factors for mastitis studied which were related to animal husbandry, personnel, mastitis control and water, only two, the herd size and practice of dry cow therapy were significantly (P < 0.05; chi 2) associated with subclinical mastitis. It was concluded that the high prevalence of subclinical mastitis in Trinidad dairy herds could significantly reduce milk production with associated economic loss. Although a majority of the risk factors studied were not found to be significantly associated with the occurrence of subclinical mastitis possibly due to confounding factors, the need to eliminate or reduce these risk factors cannot be over-emphasized.     

Epidemiological and bacteriological aspects of mastitis associated with yellow-jacket wasps (Vespula germanica) in a dairy cattle herd

The German wasp, Vespula germanica has been observed to injure teats of dairy cows, causing lesions that are associated with clinical and subclinical mastitis. The presence of skin lesions on the teats, caused by the wasps, was recorded in a dairy cattle herd located in the Samaria foothills during July-October 1999. Wasp-inflicted injuries were found in 43.6% (58 of 133) of the adult cows and 1.4% (one of 71) of the first-calving cows. They were located in 42.4% of cows (n = 25) on all quarters, 18 cows (30.5%) had lesions on the front quarters and 27.1% (n = 16) of cows on the hind quarters only. Clinical and subclinical mastitis were diagnosed in 61% (36 of 59) and 28.8% (17 of 59), respectively, of the injured adult and first-calving cows. The most common bacterial isolates from the mastitic cows were Staphylococcus aureus 45.1% (n = 14), Streptococcus dysgalactiae 16.1% (n = 5), Streptococcus spp. 19.4% (n = 7) and others 13.9% (n = 5). The loss of milk production was estimated at 300 kg milk for each cow injured by wasps and exhibiting clinical mastitis. An increase in the bulk-milk somatic cell count, from 186 x 103 at 1 month prior to the outbreak to a peak of 1200 x 10(3) in the post-outbreak month, was noted. The culling rate reached 13.6% (eight of 59) of the affected cows. In summary, the considerable economic losses caused by the wasp infestation resulted from decreased milk production and a decline in milk quality, culling of affected cows, and increased demand for use of drugs and veterinary care.     

B‐Mode and Doppler Sonography of the Mammary Glands in Dairy Goats for Mastitis Diagnosis

This study aimed to evaluate the sonographic characteristics of the udder and teats and to determine the Doppler indexes of mammary artery in healthy and undergoing subclinical and clinical mastitis goats. Thirty animals among Saanen and Alpine Brown goats were arranged in three groups, healthy goats (HG), goats with subclinical mastitis (SMG) and goats with clinical mastitis (CMG). Using the B‐mode, the sonographic characteristics (echotexture and echogenicity) and biometry (diameter and area of the udder cistern, diameter and area of the teat cistern and thickness of the teat wall) were evaluated. Using Doppler ultrasonography, the vascular indexes of the mammary artery were obtained. It was observed hyperechogenicity with solid component in the gland cistern when comparing animals with clinical mastitis and healthy mammary tissue. Regarding the echotexture of the breast tissue, there was heterogeneity in the mammary parenchyma on the three groups, for the milk, it was observed homogeneity for animals on HG and SMG and heterogeneity for animals on CMG. Grey‐scale quantitative assessment revealed increase in echogenicity (mean value) for all the structures when comparing the three groups. Biometry did not reveal statistical difference between groups, for none of the evaluated structures. Doppler examination of the mammary artery showed the decrease of end diastolic velocity and raise of pulsatility index between groups. The association of B‐mode and Doppler ultrasonography is useful for the evaluation of the udder of dairy goats with mastitis. It is a sensitive and specific method for the study of this disease. Doppler mode was unable to establish reliable criteria for diagnosis of subclinical mastitis. Moreover, the quantification of echogenicity is a useful technique for the evaluation of the milk in animals with mastitis; therefore, it is suggested that it can be used as complementary technique for the diagnosis of mastitis in goats.     

The descriptive epidemiology of udder lesions in Northern Iraqi ewes

Pathological lesions of the mammary glands were studied in 3693 randomly selected ewes in Northern Iraq between July 1988 and June 1989. The lesions were encountered in 3.9% (143/3693) of the ewes. Prevalences of mastitis, neoplasms and miscellaneous lesions were 3.5% (131/3693), 0.2% (6/3693) and 0.2% (6/3693), respectively. Five patterns of mastitis were encountered: acute suppurative, subacute suppurative, subacute non-suppurative, chronic suppurative and chronic non-suppurative. Mammary neoplasms encountered in the present study included adenocarcinoma, papilloma of the skin of the teat and haemangiopapilloma of the cistern. The miscellaneous lesions of the mammary gland included subepidermal cysts; hyperplasia, metaplasia and dysplasia of the ductal epithelium; thelitis; the presence of corpora amylacia; and blind teats. The highest prevalence of mastitis was during May and June. Significant differences were not encountered in the prevalence of mastitis in various age groups and breeds. Bacteria that were isolated from mastitic udders included Staphylococcus spp., Corynebacterium pyogenes, Pasteurella hemolytica, Pasteurella multocida, and a mixture of Escherichia coli and Staphylococcus spp. The staphylococci were isolated from almost all types of mastitis, C. pyogenes from chronic supparative mastitis, and the pasteurellae from the acute and subacute mastitis. Fungi were not isolated.     

Transmission of Mannheimia haemolytica from the tonsils of lambs to the teat of ewes during sucking

Objective of the work was to study whether Mannheimia haemolytica may be transmitted from the mouth of the lambs into the teat of the dam during sucking. We compared bacterial populations within the teat duct and milk of ewes immediately before and immediately after sucking by the lambs. Tonsils of lambs of the ewes were swabbed. M. haemolytica strain DAG21T recovered from a teat duct of a ewe was compared to strain DAG21R recovered from the tonsils of her lamb by using 16s rRNA sequencing. We used those two isolates and another one of known pathogenicity, for challenging ewes: (i) 2-mm deep into healthy teats, (ii) 2-mm deep into teats with chapping lesions or (iii) into the cistern of healthy mammary glands. Of samples collected before suckling, 20/792 were bacteriologically positive, and of those after, 50/792 were bacteriologically positive (P < 0.001); in 37 cases, a negative sample became positive. One M. haemolytica (DAG21T) was recovered after suckling from a teat duct of a ewe. The organism was isolated from 57/90 tonsillar swabs from lambs. Risk of infection of ewe’ teats was 0.004 throughout lactation, being greatest (0.021) during the 3rd week of lactation. The 16s rRNA sequences of strains DAG21T and DAG21R were identical over 1450 nucleotides. Phylogenetic analysis showed that the two isolates clustered together with isolates of M. haemolytica. Organism deposition into healthy teats caused subclinical mastitis; deposition into teats with lesions or directly into mammary gland caused clinical mastitis. When results of inoculation of the three strains were compared between them, statistical significance was always P > 0.9. Results provide clear evidence that suckling by lambs can lead to transmission of M. haemolytica into the teats of the ewes; the bacteria have the potential to cause mastitis if circumstances are favourable.     

Effects of teat cistern mural biopsy and teatoscopy stab versus longitudinal incision with or without tube implant on incisional healing in lactating dairy cattle

Effects of teat cistern mural biopsy and full-thickness stab and longitudinal incisional healing were evaluated experimentally on clinically normal teats in 12 lactating dairy cattle. Each teat on each cow was assigned by Latin-square design to 1 of 4 surgical interventions: (I) teatoscopy only; (II) teatoscopy, stab incision, and mural biopsy; (III) longitudinal incision and mural biopsy; and (IV) longitudinal incision, mural biopsy, and tube implantation. Teatoscopy was done with a 4-mm OD arthroscope introduced through the teat canal and attached to a television camera. Teatoscopy was quicker to perform and provided a more detailed videotaped examination of the teat and gland cistern, compared with gross inspection through a longitudinal incision. In intervention-II cows, the Ferris-Smith biopsy instrument jaws introduced through a longitudinal 1-cm midteat stab incision were easy to visualize and manipulate accurately. Stab incisions closed with only 1 or 2 skin sutures healed without complications in all 12 teats. On palpation, stab incisions were significantly (P less than 0.01) less thick than longitudinal incisions at 8 weeks and were microscopically indistinguishable from the normal tissue. However, in 24 teatoscopically examined teats, 9 (38%) had microscopic evidence of teat canal injury and 12 (50%) of the quarters developed mastitis. This was attributed to trauma resulting from introduction of the arthroscope through the teat canal. Intervention III yielded satisfactory results with the least complications. All 12 longitudinal incisions healed by primary intention, and all teats remained patent. Mastitis developed in 4 (33%) quarters. Intervention IV caused considerable complications associated with the tube implant and no improvement in biopsy site healing, compared with interventions II and III. Eleven longitudinal incisions healed by primary intention. One incision dehisced, 2 (17%) tube implants dislodged, 2 (17%) became obstructed proximally, and irritations of the mucous membrane developed in 2 teats proximally and in 6 teats distally. Mastitis developed in 6 (50%) quarters. Longitudinal incisions healed with moderate submucosal fibrosis. All sutured incisions had multifocal microgranulomata in which suture material was in various stages of degradation. At 8 weeks, localized teat wall thickening could be detected at incisional and biopsy sites, but did not obstruct milk flow. Excessive granulation tissue was at the biopsy sites (72 total) at 2 weeks, and at this time, the sites were partially covered by metaplastic squamous epithelium. However, by 8 weeks, 71 (98%) of the areas were replaced by fibrous tissue with minimal protrusion into the teat cistern.     

Effect of application of an external teat sealant and/or oral treatment with a monensin capsule pre-calving on the prevalence and incidence of subclinical and clinical mastitis in dairy heifers

AIM: To assess the effect of applying an external teat sealant or a slow-release intraruminal monensin capsule pre-calving on the prevalence and incidence of subclinical or clinical mastitis in dairy heifers post-calving. METHODS: The studies were undertaken in 13 herds. In two herds application of an external teat sealant was compared with a negative control; in nine herds treatment with monensin was compared with controls, and in two herds treatments were applied in a 2 x 2 factorial design. Heifers were randomly assigned within herd to be treated with a slow-release intraruminal device containing 32 g monensin (n=383), or left as untreated controls (n=389), approximately 30 days before the start of the spring calving period; or to be treated with a latex external teat sealant (n=206) when calving was impending, or be left as untreated controls (n=205). Milk samples were collected from each gland between 0 and 5 days after calving and from any gland diagnosed with clinical mastitis. The effect of the treatments on the prevalence of intramammary infection (IMI), i.e. subclinical mastitis, and clinical mastitis were initially analysed at the univariate level, with associated variables (p<0.2) being used in construction of multivariable models. RESULTS: The prevalence of IMI was 18.4% at the gland level, and coagulase-negative staphylococci followed by Streptococcus uberis were the most common isolates. Treatment with an external teat sealant reduced the prevalence, compared with controls, of any IMI (12.1 (SE 1.7)% vs 16.5 (SE 2.1)%, respectively; p=0.05) or IMI caused by a major pathogen (3.8 (SE 0.8)% vs 6.0 (SE 1.1)%, respectively; p=0.05). Monensin treatment did not affect the prevalence of any IMI (p=0.68) or IMI due to a major pathogen (p=0.11). The cumulative incidence of clinical mastitis was 14.2%. Neither monensin treatment (p=0.47) nor application of an external teat sealant (p=0.71) altered the risk of clinical mastitis. There was no interaction between the monensin and external teat sealant in the two herds where the treatments were applied in a 2 x 2 factorial design. CONCLUSIONS: Application of an external teat sealant resulted in a lower prevalence of any IMI and of an IMI caused by a major pathogen. Despite monensin reducing the mobilisation of body tissue and the risk of subclinical ketosis, it had no effect on the prevalence or incidence of IMI or clinical mastitis. CLINICAL RELEVANCE: Application of an external teat sealant is an option for reducing the prevalence of IMI in pasture fed dairy heifers.     

Prevalence of bovine subclinical mastitis and antibiotic susceptibility patterns of major mastitis pathogens isolated in Unguja island of Zanzibar,Tanzania

A cross-sectional study was conducted between January and July 2014 in Unguja island of Zanzibar to establish prevalence of subclinical mastitis (SCM) in smallholder dairy cows and patterns of antibacterial susceptibility of major mastitis pathogens isolated. A total of 416 dairy cows from 201 farmers were randomly selected from three districts of Unguja Island to participate in the study. Questionnaire interview, field observation, individual cow examination, California Mastitis Test (CMT) and bacteriological examination were carried out. Kirby-Bauer disc diffusion technique was used to test drug sensitivity for common bacteria isolated. Based on CMT results, the overall prevalence of SCM was 28.6, 48.8 and 64.7% at quarter, cow and farm level, respectively. Prevalence of bacterial infection was recorded at 42.9, 70.9 and 78.6% at quarter, cow and farm examined, respectively. The common bacteria isolated included Staphylococcus aureus (36.8%), Pseudomonas aeruginosa (17.8%), Staphylococcus epidermidis (16.1%), Klebsiella spp. (9.5%), Micrococcus spp. (6.3%) and Escherichia coli (4.9%). In conclusion, findings of this study demonstrated high level of subclinical mastitis at farms, cows and quarters levels with both contagious and environmental bacterial pathogen involved. Therefore, efforts should be directed to the decreased subclinical mastitis by improving sanitary measures and proper milking practice.     

Clinical, bacteriological, cytological and pathological features of teat disorders in ewes

We describe the features of 13 cases of teat disorders in ewes, as follows: lengthy teats (one case), papilloma infection (two), staphylococcal dermatitis (one), nodules and abscesses (two), teat bites (three), stenosis (one), orf (two), compressed teat (one). Mannheimia haemolytica, Staphylococcus epidermidis, Staphylococcus simulans or Staphylococcus aureus were isolated from samples. Sub-epithelial leucocytic infiltration at the teat duct-teat cistern border, but not lymphoid nodules, was the salient histological finding in the teat. Leucocytic infiltration and destruction of parenchyma were evident in the mammary gland. The results provide field evidence suggesting that teat lesions predispose ewes to mastitis.