Changes in the bovine teat canal during the nonlactating period and early lactation, as measured by teat canal impressions.

Changes in dimensions of impressions of the lumen of the teat canals of 13 cows were examined at 17 intervals during the nonlactating period and early lactation. Impressions were made of teats of 2 diagonally opposed quarters of each cow, using dental impression material. Impression length was measured and cross sections of the impressions at the proximal (distal to Furstenburg rosette), distal (proximal to the teat orifice), and middle (midway between the 2), portions of the teat canal were prepared. Cross sections were photographed and enlarged, and circumference and area were determined by use of planimetry. Effects of making repeated impressions during the nonlactating period and early lactation on new infection rates and somatic cell counts were also assessed. Mean length of teat canal impressions decreased between days 0 and 3 of involution and during the prepartum periods. Depending on the level from which they were taken, cross-sectional areas of impressions tended to increase or increased significantly during the period of involution and again in the prepartum period. Significant changes in cross-sectional area were not observed during early lactation. Changes in circumference of proximal, middle, and distal cross sections followed trends similar to area measurements, but were more variable and differences were less statistically significant. On the basis of our findings, we suggest that heightened susceptibility to new infection during mammary involution and the prepartum period may be attributable, in part, to changes in the patency of the teat canal. Making impressions repeatedly throughout the nonlactating period and early lactation did not affect the number of new intramammary infections.     

Influence of milking technique and lactation on the bovine teat by means of ultrasonographic examination

The teats of Brown Swiss and Austrian Simmental cows, divided into two groups, one milked by means of an automatic milking system, the other using a conventional milking parlour, were examined monthly by ultrasonography. Aim of the study was to compare the effects of two different milking machines upon the structures of the bovine teat canal and wall by ultrasonography and thereby evaluate ultrasonography as a research tool for visualisation of different influences on the bovine teat. Length and thickness of the teat canal and teat wall thickness were measured and analysed. During lactation, teat canal length and thickness increased in both groups, teat canal length decreased in conventional milked cows at the end of lactation. Shorter and narrower teat canals were observed in automatic milked cows. Differences between the groups in teat canal length and thickness were determined in early lactation. During lactation teat wall thickness showed a slight increase. Automatic milked cows displayed thinner teat walls than cows milked in the milking parlour. Teat morphology was influenced by the number and duration of lactations, milk yield, quarter of the udder and time and date of examination. It was concluded that the effect of the two different milking machines caused significant differences in bovine teat morphology and that ultrasonography proved to be an appropriate method for visualising influences of the milking technique on the bovine teat.     

Obliteration of all teat cisterns in a cow

A rare case of agalactia in a 7 year old cow is described. At the start of the 5th lactation all the teat cisterns were obliterated. Post mortem x-ray examination, with bariumsulfate contrast deposition in the glandular--and the teat cisterns, showed horizontal membranes in the proximal half of the teat cisterns. The membranes were 13--20 mm thick and consisted of fibrous tissue. Glandular tissue, distal parts of teat cisterns and teat canals were normal, and there was no sign of mastitis Obliteration of the teat cisterns, which had developed during the dry period, between the 4th and 5th lactation periods, were assumed to be a result of improper machine milking. The importance of overmilking is discussed.     

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

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

Effects of feeding management and time of day on the occurrence of self-suckling in dairy goats

The occurrence of self-suckling was recorded in 21 dairy goats during periods of 20 minutes at three different times per day (immediately after milking and the first feed, immediately after the second feed and in the afternoon) for 27 days (divided into three experimental periods of nine days). As expected, negative associations between milk yield and the frequency of self-suckling were observed (P<0.05). Goats suckled on their own right teat more frequently than on the left teat. The width of the right teat (measured at the middle of the teat) was positively associated with the frequency of self-suckling after controlling for the width of the left teat. A higher self-suckling frequency was observed immediately after milking than in the other two periods of the day. The frequency of self-suckling by each goat was reduced when animals were supplemented ad libitum with wheat straw in addition to their ordinary feed.     

Occurrence and radiological studies of different teat changes in milk cows

The aim of this study was to investigate the incidence of different teat lesions in cows that cause obstruction of milk flow. 18,400 teats were palpated in Konya slaughterhouse. From these 1000 hard milking or obstructed teats were found (5.4%). Based on the radiographical results, distal 1/3, proximal 2/3, complete teat lesions and congenital obstructions were found in 70.1, 16.6 and 0.7% respectively.     

Infrared thermography and ultrasonography to indirectly monitor the influence of liner type and overmilking on teat tissue recovery

Eight Danish Holstein cows were milked with a 1-mm thick specially designed soft liner on their right rear teat and a standard liner mounted under extra high tension on their left rear teat. Four of the animals were overmilked for 5 min. Rear teats were subjected to ultrasound examination on the first day and to infrared thermography on the second day. Teats were submersed in ethanol 20 min post-milking on the second day. Ultrasonography measurements showed that teat canal length increased by 30-41% during milking. Twenty minutes after milking, teats milked with modified standard liners still had elongated teat canals while teats milked with the soft liner were normalized. Overmilking tended to increase teat wall thickness. Approximately 80% of variability in teat canal length, from before teat preparation to after milking, could be explained by changes during teat preparation. Thermography indicated a general drop in teat temperature during teat preparation. Teat temperature increased during milking and continued to increase until the ethanol challenge induced a significant drop. Temperatures approached pre-challenge rather than pre-milking temperatures within 10 minutes after challenge. Teat temperatures were dependent on type of liner. Mid-teat temperatures post-challenge relative to pre-teat preparation were dependent on overmilking. Thermography and ultrasound were considered useful methods to indirectly and non invasively evaluate teat tissue integrity.     

Microbiological colonisation of bovine teat canal--significance and influencing factors

The teat canal of lactating dairy cattle is of particular importance for the defence of facultative pathogenic and pathogenic microorganisms (e.g., staphylococci) invading the bovine udder. Furthermore the canal is usually colonized with microorganisms, too. In addition to microorganisms inhibiting mastitis pathogens the teat canal is colonized by staphylococci. The microbial colonization can be influenced by the environment of the animals, the care and disinfection of the teat skin and indirectly by the effects of forces being associated with machine milking. Because of vacuum fluctuations occurring under the teat tip microorganisms, which colonize the teat canal, can invade the bovine mammary gland and cause infections there. This paper gives a review of the microbial colonization of the bovine teat duct and of influencing factors on the microbial populations as well as of the significance of the teat canal colonization for the development of mastitis.     

The association between teat end hyperkeratosis and teat canal microbial load in lactating dairy cattle

Most pathogens that cause bovine mastitis invade the udder lumen through the teat canal. Amino acids and intercellular lipids may support microbial colonisation of the teat canal epithelium by pathogenic microorganisms. The aim of this study was to investigate the association between teat end hyperkeratosis, which is induced by machine milking, and teat canal microbial load. Contralateral teats, which differed in teat end hyperkeratosis scores, were identified in a split-udder experiment. The teat canal's microbial load was evaluated using the wet and dry swab technique. Staphylococcus (S.) aureus, Streptococcus (Sc.) uberis, Escherichia (E.) coli and other coliforms were detected by agar plate cultures. The positive detection of E. coli and the log(10)-transformed E. coli load of a teat canal were significantly associated with the teat end hyperkeratosis score (P<0.05). There were significant differences with respect to positive findings for E. coli, as well as the microbial load of E. coli and Sc. uberis, between the less-calloused and the more-calloused teat of a pair. For S. aureus, no significant associations between hyperkeratosis score and teat canal microbial load were detected. In general, a teat with a highly calloused teat end had an increased teat canal microbial load compared with the contralateral teat, characterised by a lower callosity. The results of the present study indicate that the environmental pathogen load is associated with teat end hyperkeratosis. Further research is needed to identify factors that may affect teat canal microbial load in lactating dairy cattle.     

Teat characteristics in relation to animal temperament during milking in buffaloes,and comparison of buffalo and cow teat morphology

This study aimed to examine the teat characteristics in relation to the animal temperament during milking in the Anatolian buffaloes using ultrasonographic, histomorphological and immunohistochemical methods. The teat canal length (TCL), teat wall thickness (TWT), teat cisternal diameter (TCD), teat diameter (TD), teat length (TL), and teat circumference (TC) values in docile (n = 5) and nervous (n = 7) buffaloes were measured at the 0th, 3rd and 6th minute of stimulation. In additional experiments, comparative histomorphology and immunohistochemical examinations of buffalo (n = 7) and cow teats (n = 8) were performed. It was determined that post-stimulation mean TCL values were significantly higher in nervous buffaloes than those of teats in docile buffaloes (p < .05). A significant positive correlation between TCD and TD, TL and TC in both docile and nervous buffaloes was noted (p < .05). Unlike nervous buffaloes where only 3/14 teat canals were open by 3rd minute of milking stimulation, almost all (9/10) teat canals were observed opened in docile buffaloes. There were fewer muscle but more collagen bundles in buffalo teats compared with cow teats. It seems that temperament of animal during milking effects the milking efficiency, and in nervous buffaloes, probably the stimulation alone may not be sufficient for opening of the teat canal and hence achieve complete milking.     

Blood flow to the distal part of the teat (mammary papilla) of lactating dairy cows

Relative blood flow to tissues of the distal part of the teat (mammary papilla) in 5 lactating dairy cows was determined, using 15-microns nonradioactive carbonized microspheres. Highest relative blood flow occurred in the epithelial region (zone A) of the teat canal (papillary duct) which comprised both teat canal epithelium and papillated portion of the stratum papillare. Blood flow to these tissues was more than 4 times greater than blood flow to equivalent tissues of the mucosal rosette. The high rate of metabolic activity indicated by this relatively high blood flow may be required to support secretion of antimicrobial substances and continual synthesis of epithelial cells to replace those lost during milking.     

Teat burns in dairy cattle – the prognosis and effect of treatment

Twenty cows and 20 uncalved 20 month old heifers with severely burnt teats were studied. Ten of each group received topical treatment with a mixture of lanoline, cetrimide and dimethyl sulphoxide or vitamin A and petroleum jelly, respectively. Prognosis for survival and future normal milking ability was poor in heifers (8 subsequently normal of 20 assessed) but moderate in cows (9 cows with normal and 5 cows with partial machine milking ability of 18 cows fully assessed). Treatment did not significantly increase the rate of epithelialisation of wounds. Topical treatment had no effect on the prognosis of heifers. However treated cows were more likely than control cows to survive and to show adequate teat function following subsequent calving. Severe clinical mastitis prior to calving, teat distortion and teat canal constriction were common sequelae. Recommendations on the management of heifers and cows with severely burnt teats are made.     

Effects of Machine‐milking on the Bacterial Flora of Teat Duct and Mammary Gland of Ewes

In total, 308 paired‐samples of teat duct material and milk, were collected before and 50–70 min after machine‐milking, from 30 ewes. Samples were processed bacteriologically. For analysis of results, we compared changes in bacterial isolation following milking, for duct and milk samples; statistical significance was assessed by the Sign Test. Bacteria were isolated from 18 (6%) duct and 19 (6%) milk samples collected before the milking procedure; respective figures after it, were 81 (26%) and 33 (11%). In 77 (25%) cases, bacteriological findings in the two duct samples of each pair were different; in seven cases bacteria were isolated only before, whilst in 70 cases bacteria were isolated only after milking (P < 0.005); respective results for milk samples were 26 (8%): 6 and 20 cases (P = 0.693). The majority of bacterial isolates were staphylococci, accounting for 63% of 99 isolates. The milking procedure predisposes to entrance of bacteria into the teat duct; however, increased bacterial isolation from the teat did not result to increased mammary infections, likely as a consequence of defence mechanisms present in healthy teats.     

Teat stimulation-induced oxytocin and catecholamine release in pregnant and lactating Holstein heifers

The effect of manual teat stimulation (milking paradigm) on release of oxytocin, epinephrine and norepinephrine was studied in (1) 15 heifers at 100, 150, 200 and 250 d of gestation and at 30 and 90 d of lactation (during machine milking) and (2) simultaneously in six heifers at less than 100 d and in six heifers at greater than 200 d of gestation. Oxytocin responses to teat stimulation, including peak heights and area under the response curves, at 150, 200 and 250 d or at greater than 200 d of gestation were similar and were significantly greater than responses at 100 d or at less than 100 d. Responses to milking were lower at 90 d compared to responses at 30 d. Catecholamines were measured only during gestation and were generally not affected by teat stimulation. Epinephrine levels were significantly higher at 200 and 250 d compared to levels at 100 and 150 d. Baseline oxytocin concentrations and responses to teat stimulation were greatest at 150 d of gestation when epinephrine levels were still low, suggesting that stimulatory mechanisms responsible for the release of oxytocin develop and/or are expressed prior to the development of inhibitory sympathetic mechanisms. For norepinephrine, linear analyses did not show significant responses to teat stimulation overall. However, elevated norepinephrine responses (greater than .2 pmol/ml) following teat stimulation were seen in 28 of 51 trials, and large oxytocin responses (greater than 75 pg/ml/min) were seen predominantly only when norepinephrine responses were low (less than = .2 pmol/ml).     

Effects of quarter individual and conventional milking systems on teat condition

An on-farm experiment was performed to investigate the effects of two milking systems on teat condition. An auto-tandem milking parlor made by GEA^® with a conventional milking cluster (CON) and a single tube milking system called MultiLactor^® (MULTI) from Siliconform GmbH were tested. For both milking system, in total 73 animals were milked over a period of seven months. To assess the effect of milking on teat condition, each teat was scored according to teat-condition evaluation systems. To evaluate teat condition, the teat color, ring formation at the teat base and formation of teat hyperkeratosis were assessed. The evaluation was conducted once a month after milking. The collected data were then statistically analyzed with generalized linear mixed models. The only differences found between the two milking systems occurred with respect to their effect on teat color. MULTI showed significantly better scores compared to CON. There were no significant differences between the milking systems with regard to teat-end hyperkeratosis and ring formation at the teat base.     

Endotoxin-induced bovine mastitis: arachidonic acid metabolites in milk and plasma and effect of flunixin meglumine

Arachidonic acid metabolites (AAM) were measured in milk and plasma during the course of acute endotoxin-induced mastitis in 12 lactating cows. Mastitis was induced by intramammary challenge exposure with 10 micrograms of Escherichia coli (026:B6) endotoxin. Endotoxin was injected into the teat cistern via the teat canal of a single randomly selected rear quarter of each cow. Concentrations of prostaglandin (PG) F2 alpha and thromboxane (Tx) B2 in fat-free unextracted milk and of 15-keto-13,14-dihydro-PGF2 alpha in plasma were measured by radioimmunoassay. Total production of AAM in milk was determined by measuring quarter milk production. The AAM were compared in 6 cows administered flunixin meglumine (1.1 mg/kg of body weight) and in 6 cows administered saline solution. Concentrations of TxB2 in milk were significantly (P less than 0.001) increased during the early course of acute mastitis in endotoxin-treated quarters of cows not administered flunixin meglumine. Peak concentrations of TxB2 in milk occurred at 8 hours after endotoxin inoculation. Flunixin meglumine treatment produced significant (P less than 0.05) reductions in milk TxB2 and plasma 15-keto-13,14-dihydro-PGF2 alpha concentrations. Concentrations of PGF2 alpha in milk and total PGF2 alpha and TxB2 production per quarter per milking were not significantly influenced by endotoxin challenge or by flunixin meglumine treatment.     

Influence of milking technique, milking hygiene and environmental hygiene parameters on the microbial contamination of milking machines

It was the aim of this study to investigate the effect of various factors of the milking technique, milking hygiene and environment on microbial contamination of the milking machine. In 31 dairy herds, the degree of bacterial contamination was examined by taking swabs at four locations (teat cup liner, claw, short and long milk tube) before the milking procedure was started using a standardized protocol (DIN ISO 6887-1:1999). Furthermore, the total germ count was determined in the first milk entering the bulk tank as well as in the bulk tank milk following milking. For each farm, the quality of the milking process and the condition of the milking machine as well as of various environmental factors were recorded. A subjective evaluation of the status of the milking cluster or other parts of the milking machine ("good" or "moderate-poor") gave more information about bacterial contamination than the determination of age and type of material used. A temperature of the rinsing water of < 42 degrees C increased the contamination with Pseudomonas spp. and coliform bacteria. Milking clusters kept out of the cluster pick-up between milking had a higher risk of microbial contamination. Various methods of teat cleaning before milking or of postmilking teat disinfection did not affect the contamination of the milking machine and the bulk tank milk with environmental bacteria. Furthermore, type of bedding material affected bacterial contamination of milking clusters and bulk tank milk. In conclusion, our results suggest that the microbial contamination of the milking machine is not only influenced by the sanitation pro-     

New aspects of the physiology of milking with special reference to the teat smooth musculature in teat rubber-free extraction

The following frequencies of change between 30 kPa milking vacuum and atmospheric pressure were used in a milking experiment with single-space cups: 0.05 Hz, 0.1 Hz, 0.2 Hz, 0.35 Hz, 0.5 Hz, 0.65 Hz, 0.8 Hz, and 0.95 Hz. Milking cup pressure and instantaneous milk flow rate through the teat canal were repetitively recorded ten times per second. Four clearly distinguishable and reproducible forms of flow rate oscillations were observed across several sucking phases together with four equally distinguishable and reproducible forms of profiles of a variable milk flow rate within one sucking phase. The occurrence of those differentiated forms of milk flow was found to be correlated primarily with both the sucking phase frequency applied and the average milk flow rate. These findings seem to be indicative of active control of teat canal diameter or milk flow rate by the unstriated teat musculature.     

Efficacy of a germicidal post milking barrier-type teat dip in preventing intramammary infections

Five commercial dairy herds with 269 lactating cows participated for 12 months in a field trial to determine the effectiveness of a barrier teat dip containing chlorous acid/chlorine dioxide germicide. The right quarters of the cows in two herds and the left quarters of the cows in three herds were dipped in the experimental teat dip after the removal of the milking machine. The other quarters were dipped in a conventional 0.5 per cent iodophor product. Compared with this control product, teat dipping with the experimental dip reduced the number of new intramammary infections by 18.8 per cent, infections with major pathogens by 13.6 per cent, infections with minor pathogens by 16.8 per cent and clinical mastitis by 33.3 per cent. Statistical analysis indicated a trend towards decreased intramammary infections with coliforms and coagulase-negative staphylococci when the experimental teat dip was used. It was concluded that under the conditions of this investigation it was effective in preventing new infections due to both contagious and some environmental pathogens. However, the data suggested that it could adversely affect the condition of the skin of the teat when it was used after incorrect preparation of the udder.     

Short- and longterm results after surgical treatment of teat stenosis in the region of Fürstenberg's rosette using theloresectoscopy: 15 cases (1999-2000)]

Teat obstructions cause considerable financial loss in dairy industry. Recently, progress in teat surgery was made by the use of minimal invasive surgical instrumentation. The technique of theloresectoscopy as well as short- and long-term results of this surgical intervention are presented in this study. The clinical reports of 15 dairy cows with distal teat obstructions operated with the theloresectoscope between May 1999 and January 2000 at the clinic for ruminants, Department of clinical veterinary medicine, University of Berne were reviewed. Data collected by telephone conversation with the owners included: somatic cell count and milk flow at machine milking during the lactation of surgery (lactation 1), as well as during the lactation following surgery (lactation 2). Eighty-seven percent of the owners reported normal milk flow during lactation 1 and 93% during lactation 2. Considering the fact that only 46.7% of the cows showed negative results in the California mastitis test (CMT) during lactation 1, many owners reported a high somatic cell count being a disadvantage of this surgical technique. Normal (negative) CMT results during lactation 2, however, were reported by 80% of the owners. Isolation of Staphylococcus aureus explained the high somatic cell count in 2 of 15 cases. In conclusion, theloresectoscopy is a valuable minimal invasive surgical technique that can be fully recommended for treatment of distal teat obstructions in dairy cows.