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

Abstract

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.

Vacuum level for opening the teat sphincter and the change in the teat end wall thickness in response to the machine milking of indigenous Greek goats

“…Phenotypic correlations between milk fractions, teat end wall thickness and vacuum for opening the teat sphincter in goats of the indigenous Greek breed gested that these findings depended on the characteristics of used materials and proved that the modifications in TEWT depended on the diameter of the liner as well as on its stiffness. Gleeson et al (2004) also stated that the liner design appeared to have a bigger effect on the teat tissue changes than pulsation characteristics or vacuum level. In cows Hamann and Mein (1996a) recommended that the teat thickness changes after milking should be lower than +5% in order to prevent excessive teat oedema and greater than -5% in order to limit an excessive compression load of the liner over the teat.…”

“…In cows, an increase in the teat end wall thickness (TEWT) was observed after milking (Hamann and Mein, 1990). Gleeson et al (2004) found in cows that vacuum levels of 50 and 40 kPa gave similar changes in the teat tissue after machine milking. In contrast Le Du and Taverna (1989) observed a reduction in TEWT after milking.…”

“…The above results suggest an influence of machine settings and especially of too high vacuum level applied to the teat (Hamann et al, 1993) as well as of the teat cup liner design and characteristics (Le Du and Taverna, 1989). The liner design appears to have a bigger effect on the teat tissue changes than pulsation characteristics or vacuum level (Gleeson et al, 2004).…”

Objective measuring technique for teat dimensions of dairy cows

“…Consequently, the teats may become more sensitive for the entry of pathogens with intramammary infections as a result. Therefore, the condition of the teat plays a considerable role in the incidence of mastitis infections (Bhutto, Murray, Woldehiwet, 2010;Gleeson, O'Callaghan, Rath, 2004). Besides the greater risk on penetration of bacteria into the udder, these changes in teat condition are generally accompanied by discomfort and pain, which negatively influence the milking process.…”

“…Besides the greater risk on penetration of bacteria into the udder, these changes in teat condition are generally accompanied by discomfort and pain, which negatively influence the milking process. The design of the teatcup liner has a larger effect on teat tissue changes than other machine settings (Gleeson et al, 2004). In addition, the liner design has proven to have a great influence on milking characteristics (Mein, Reinemann, O'Callaghan, Ohnstad, 2003).…”