Effect of different milking routines on milking-related release of the hormones oxytocin, prolactin and cortisol, and on milk yield and milking performance in Murrah buffaloes

Abstract

Milking-related release of oxytocin, prolactin, and cortisol was studied following three pre-milking treatments. Six Murrah buffaloes were treated with direct application of milking cluster (O), a 1-min pre-stimulation (M), and combined feeding and pre-stimulation (MF). Machine milk yield, stripping yield and milk composition were recorded. Milk ejection occurred significantly earlier with MF than M and O (P<0·05; 2·50, 5·10 and 6·33 min, respectively). In all treatments, milk ejection occurred with small increases >3–5 ng/l in oxytocin concentration. Increase in oxytocin concentration over a threshold level and milk ejection occurred simultaneously and were closely correlated (r=0·83, P<0·05). There was a positive correlation between total time oxytocin concentration remained elevated over threshold levels and machine yield (r=0·86, P<0·05). For treatment O, milk ejection was inhibited during machine milking, while a marked increase in oxytocin occurred during hand stripping (6 and 16 ng/l, respectively). For treatment M, mean oxytocin concentrations remained unchanged during pre-stimulation but increased during subsequent machine milking and hand stripping (6·38, 18·06 and 12·36 ng/l, respectively). For treatment MF, although there was a 3·6-fold increase during pre-stimulation, oxytocin increased by 10-fold and 3-fold during machine milking and hand stripping, and was significant for machine milking (P<0·05, 17·32, 47·86, 18·13 ng/l, respectively). Milk-ejection-related cortisol release was visible only in treatment MF. For treatments O and M, prolactin concentration increased prior to the increase in oxytocin. The stripping yield was higher, and fat content in the stripping yield significantly lower, for treatment O indicating incomplete milking. Thus buffaloes are easily disturbed even by small changes in milking routines.

Pre-milking mechanical teat stimulation and milking performance of dairy buffaloes in early lactation

“…In our experiment the time elapsed from attachment of the milking cluster until its automatic removal was less than 8 min both for buffaloes subjected to fast pulsation, and for buffaloes subjected just to washing of the teats before attaching the milking unit. This value is markedly lower if compared with manual removal of the teat cups (Thomas et al, 2005;Bava et al, 2007;Caria et al, 2011), confirming that the operator's choice to not use automatic cluster removers, as frequently occurs in dairy buffaloes milking, strongly influences the milking time. In buffaloes milked by AMS the milking duration averaged 8.3±2.7 min (Caria et al, 2014), even if in that case it was calculated as the time between the buffalo identification and the last teat-cup detachment.…”

“…The application of an attachment delay of 60-90 s after stimulation before milking is recommended to ensure immediate and continuous milk flow after the start of milking in dairy cows (Rasmussen et al, 1992). Thomas et al (2005) found that milk ejection in Indian Murrah buffaloes occurred significantly earlier for machine milking with in-parlour feeding and 1-min manual pre-stimulation (washing, drying and short massage of teats) than for machine milking without manual pre-stimulation or in-parlour feeding. This highlighted that a careful teat preparation and pre-stimulation are important preconditions for successful milk removal also in dairy buffaloes.…”

“…The milk cisternal fraction in dairy buffaloes is smaller than in dairy cows (about 5% vs 20%) and frequently it is not immediately available for the milking machine as in dairy cows (Thomas et al, 2005), so teats are exposed to the vacuum without milk flow for a long time. Due to their slow milk ejection reflex and their thicker sphincter muscle around the streak canal in comparison with dairy cows, dairy buffaloes are known to be slow and hard to milk: lag time before milk let-down ranges from 1.6 to 6.3 min (Thomas et al, 2005;Bava et al, 2007;Caria et al, 2011).…”

“…Reducing the labour cost, improving the management and the productivity of farms, and increasing the hygiene of milk are the key factors for machine milking of dairy buffaloes (Ambord et al, 2010;Caria et al, 2011). At the present time, the technology and the milking machine settings usually adopted for dairy buffaloes come from dairy cows, although some morphological and physiological differences between the two species exist (Thomas et al, 2005;Caria et al, 2011).…”

“…Due to their slow milk ejection reflex and their thicker sphincter muscle around the streak canal in comparison with dairy cows, dairy buffaloes are known to be slow and hard to milk: lag time before milk let-down ranges from 1.6 to 6.3 min (Thomas et al, 2005;Bava et al, 2007;Caria et al, 2011). As in dairy cows, milk ejection in dairy buffaloes occurs in response to oxytocin release, which is induced primarily by teat stimulation Thomas et al, 2005). The application of an attachment delay of 60-90 s after stimulation before milking is recommended to ensure immediate and continuous milk flow after the start of milking in dairy cows (Rasmussen et al, 1992).…”