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ABSTRACT
Forty-eight Holstein cows were used in a randomized block design to evaluate different dry period lengths and prepartum milking frequencies (MF) on subsequent milk production, milk composition, solids-corrected milk production, dry matter intake (DMI), and energy balance. Lactating cows, milked 2 times/d, began a 7-d covariate period 35 d prior to the expected calving date. Cows were milked 0 times/d (0×), 1 time/d (1×), and 4 times/d (4×) for the last 28 d of gestation. If milk production decreased to less than 0.5 kg/milking or 1 kg/d, milking via machine ceased; however, teat stimulation continued 1 or 4 times/ d according to the treatment assignment. All cows were milked 2 times/d postpartum (wk 1 to 10). Prepartum DMI tended to be greater for 1× and 4× compared with 0×. Prepartum, cows milked 1× produced 17% less milk than cows milked 4× (5.9 and 7.1 kg/d, respectively). There were no differences in prepartum and postpartum body condition scores, body weights, and DMI. Postpartum milk production by cows following their third or greater gestation was greater for 0× and 4× compared with 1×. Postpartum milk production by cows following their second gestation was significantly decreased with increased MF (0× vs. 1× and 4×). Regardless of parity, postpartum solids-corrected milk was greater for 0× compared with 1× and 4×. Postpartum fat yield was greater for 0× vs. 4×, with 1× being intermediate. Postpartum protein yield was greater for 0× vs. 4×, whereas 0× tended to have greater protein yield than 0×. Postpartum energy balance was greater for 1× and 4× relative to 0×. Continuous milking (0× and 4×) resulted in a loss of milk production in the subsequent lactation for cows following their second gestation; however, for cows following their third or greater gestation, increasing the MF from 1× to 4× in the last 28 d of gestation alleviated the loss in milk production.
Key words: continuous milking, energy balance, milking frequency, transition period
INTRODUCTION
The benefits derived from continuous milking are greater energy balance (EB) postpartum, reduced postpartum plasma NEFA concentrations, reduced postpartum liver triglyceride concentrations (Rastani et al., 2005), and earlier first postpartum ovulation (Gümen et al., 2005). However, a 12 to 25% loss in milk production in the subsequent lactation has consistently...