Lifetime Daily Yield can be increased by reducing the age at 1st calving, increasing production per lactation and by increasing the number of lactations per cow. Several studies1,2,3 have shown that as a result of increased levels of pre-weaning nutrition, calves will reach the desired body weight to start inseminations at an earlier age and will also reach puberty earlier4. As a result, they can be inseminated earlier and calve at an earlier age. Fertility results of a trial that is part of the Trouw Nutrition LifeStart research programme on the Kempenshof farm are presented in this article5.

Calves in the LifeStart group had an increase of pre-weaning average daily gain of 155 g/day and reached the desired body weight to be inseminated earlier. The age at 1st insemination was reduced by 8 days, the age at conception was significantly reduced by 23 days and the difference was maintained until 1st calving (see table 1).

Table 1: Fertility parameters in heifers reared with an intensive feeding schedule compared to heifers reared on a restricted feeding schedule.

There was no difference in first conception rate during the 1st lactation but first conception rate during the 2nd lactation was significantly higher in the group that was fed according to an intensive milk feeding schedule (see table 2).


Table 2: First conception rate in animals reared with an intensive feeding schedule compared to heifers reared on a restricted feeding schedule..

1. Bolt, A. 2019, Meta-analysis to calculate the effect of rearing intensity on functionality of dairy cows, Research paper Mecklenburg Vorpommern Landesforschungsanstalt für Landwirtschaft und Fischerei.
2. Bar-Peled et al., 1997. Increased weight gain and effects on production parameters of Holstein heifer calves that were allowed to suckle from birth to six weeks of age. J. Dairy Sci; 80:2523-8.
3. Heras Sánchez, J, Effects of feeding a calf milk replacer with elevated levels of fat on average daily gain and fertility, 2020, Proceedings of the 2nd European Calf Conference.
4. Bruijni, T.C, Rosadiuk, J.P, Moslemipur, F, Carelli, J.E, Steele, M.A. and D.J. Ambrose, 2019, Carryover effects of pre- and postweaning planes of nutrition on reproductive tract development and estrous cycle characteristics in Holstein heifers. J. Dairy Sci. 102.
5. Leal, L, (2019). Lifetime impact of early life planes of nutrition in dairy calves, Proceedings of Smart Calf Rearing Conference, University of Guelph, Canada, November 2-5.