Prediction of lactation curve pattern for daily milk, fat, and protein yields in Egyptian buffalo

Abstract EN

Data were collected at monthly intervals over the period from february 2013 to march 2015 to select the best equation to describe the lactation curve pattern for the daily milk traits.

a total of 2265 test day records of milk yield (MY), fat yield (FY) and protein yield (PY) in the first seven lactations for 263 Egyptian buffalo cows raised at three experimental herds belonging to the animal production research institute, Egypt were analyzed.

four non linear equations were compared to predict daily milk yield traits, wood's (WOD), Wilmink's (WIL), Guo and Swalve (GS) and Cobby and Le Du (CLD).

for all models, the initial and ascending to peak daily yield phases were contributed with high variability of lactation curve pattern.

in a comparison with the WIL, the three equations (WOD, CLD and GS, respectively) had the low values with residual standard deviation (RSD), Akaike information criterion (AIC) and schwarz bayesian criterion (SBC) criteria over the first seven lactations.

Based on RSD, AIC and SBC criteria, wood's equation showed more flexibility than other models to explore lactation curve pattern for expected daily milk yield traits.

considering values obtained by the WOD model, the expected daily yield at peak, time at peak daily yield and persistency ranged from 4.59 to 7.38 kg, 5.03 to 8.23 wk and 40.26 to 65.90%, respectively for MY.

The corresponding values varied between 0.395 and0.467 kg, 5.39 and 9.35 wk and 41.53 and 72.00 %, respectively for FY and varied between 0.230 and 0.263kg, 4.05 and 8.13 wk, 40.33 and 70.41%, respectively for PY.

Moreover, higher persistency was observed for MY, FY and PY in the 1stlactation (65.90, 72.00 and 70.41%, respectively), which declined till the fifth lactation and then tended to be almost constant till the seventh one (47.60, 48.76 and 47.32%, respectively).