Milk yield in pasture-based automatic milking systems is negatively affected by variability in concentrate fed in the robot

PALLADINO, R.A.

Congreso; ADSA Anual Meeting; 2019

Feed is the main incentive to encourage voluntary cow traffic in automatic milking systems (AMS). Pasture-based AMS farmers utilizeaccess to pasture and concentrate in the robot to manage cow trafficand ensure target milk yield (MY). We hypothesized that variability inconcentrate intake (CI) fed in the robot affects negatively MY, whichmight reduce AMS profitability. A database from 17 pasture-based AMSfarms from Australia, New Zealand, and Ireland was used. We analyzed403,226 daily records over a 5-mo period (September 2018 to January2019) including cow id, stage of lactation (SOL; early = 0 to 100, mid =101 to 200, late = >201 d in milk), parity (primiparous vs. multiparous),MY (kg/d), milking frequency (MF, milkings/d), and concentrate intake(CI, kg/d as fed). We calculated average and coefficient of variation (CV)for each variable for a fixed 7-d period. We ran partial correlations (r;calculated using the MANOVA / PRINTE commands of PROC GLMof SAS Version 9.3, SAS Institute Inc., Cary, NC) to evaluate association between MY and CVMY and the other variables (CI, MF, CVCI,CVMF). The model included farm, month, SOL, and parity as fixedfactors. As expected, MY was highly and positively correlated (P < 0.01)with CI (r = 0.629) and MF (r = 0.585). Milking frequency was alsohighly and positively correlated with CI (r = 0.529). However, CV of CIand MF affected negatively both parameters. Milk yield was highly andnegatively correlated (P < 0.01) with CICV (r = −0.249) and MFCV (r= −0.229). Milking frequency was also highly and negatively correlated(P < 0.01) with CICV (r = −0.247). Our data show that milk yield inpasture-based AMS is negatively affected by variability in concentrateintake in the robot. Therefore, reducing concentrate intake variation iskey to maximize milk yield output.