RESEARCH ▶▶▶


Milk flow traits as biomarkers of lameness


BY MATTHEW WEDZERAI I


n a study recently published in Agriculture (2021), re- searchers explain how milk flow traits can act as biomark- ers of lameness in dairy cows and the impact of lameness on milk flow traits. In their study, they elaborate on the


relationship of milk flow traits to lameness. Results from their previous study had indicated that lameness influences the frequency of cow visits to the automatic milking system, the productivity of the cows and the interval between milking.


The study The aim of the current study was to investigate the relation- ship between lameness and milk flow traits as biomarkers of lameness in dairy cows. For this study, 73 healthy and 55 lame cows were selected. Lameness was diagnosed by a local specialised veterinarian, according to the standard procedure. The milking properties of cows were evaluated twice in a row – during evening and morning milking. The milk flow measurements were taken by two electronic mobile milk flow meters.


Lameness and milk yield All the milk yield traits (total milk yield per milking; milk yield during the first, second and third milking minutes) were higher in the healthy cows compared to the lame cows (Table 1). “The increase of stress in lame cows affected the milking process – weaker stimulation of milk ejection reflex and con- sequently lower milk yield in lame cows,” they said, conclud- ing that milk yield may be a good trait for better prediction accuracy of lameness. Studies show that electrical conductivity of milk is a suitable indicator trait for both clinical and subclinical mastitis. Electri- cal conductivity is determined by the concentration of anions and cations. For example, if a cow suffers from mastitis, the concentration of Na+ and Cl− in the milk increases, which leads to increased electrical conductivity of milk from the in- fected quarter. In this study, all the indicators of milk electri- cal conductivity (electrical conductivity at highest milk flow, electrical conductivity during the initial time of milking, maxi- mum electrical conductivity after reaching the highest milking speed) were higher in cows with signs of lameness compared with healthy cows.


Lameness has a major impact on herd profitability and on the health and welfare status of cows. Current research is focusing on the best use of new technologies as tools to measure and monitor the health status of cows. To increase the prediction accuracy of automatic lameness detection, associations between the independent variables should be included for effective management of performance and hoof health of dairy cows.


Milking time and speed traits All the milking duration indices (time at total milk yield, time to milk flow of 0.5 kg/minute, time of main milking phase, time at plateau phase, time at decline phase) were higher in healthy cows during both morning and evening compared to the lameness group during both milking periods. Only time of incline in milk flow from 0.5 kg/min until reach of the pla- teau phase was higher in the lameness group. On the other hand, the average values of all milking speed traits were slightly higher in healthy cows compared to in lame cows.


Bimodality in milk flow of cows Bimodality of milk flow is defined as the delayed milk ejection at the start of milking. Bimodality is associated with pre-milk- ing delay time and teat preparation and has a negative effect on milking efficiency, causing increased milking machine


Figure 1 - Cortisol concentration (µg/dL) in blood of healthy (HL) and lame (LA) cows.


HL (morning milking) HL (evening milking)


1.60 1.40 1.20 1.00 0.80


0.60 0.40 0.20 0.00


▶ DAIRY GLOBAL | Volume 8, No. 3, 2021 39


LA (morning milking) LA (evening milking)


Cortisol concentration (µg/dl)


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