Effect of Unequal Milking Intervals on Lactation Milk, Milk Fat, and Total Solids Production of Cows

Cows of three breeds were milked at 12-and 12-hr, 14-and 10-hr, and 16and 8-hr daily intervals for complete lactations~ to deternfine the effect of milking intervals on the milk, milk fat, and total solids production.Thirty-five trios were used over a 2-yr period in the experiment.The mature equivalent milk records of cows milked at 14-and 10-hr intervals were 0.3% lower, and those of cows milked at 16-and 8-hr intervals were 1.3% lower, than the records of cows milked at equal intervals.The mature equivalent milk production records of all cows averaged over 13,500 lb milk.No significant differences occurred between any two groups in the milk fat and total solids percentages or yields.There was some indication that the 16-and 8-hr intervals had a greater adverse effect on higher-producing cows in comparison to lower-producing cows, and on first-calf heifers in comparison to older cows; however, the evidence was not conclusive.Unequal intervals had no effect on udder health or the incidence of ketosis.