Table 2.
Effect of pre-pubertal feeding on heifer performance, mammary gland and milk yield (MY)
| Duration/age | Feeding regime | Response | Authors |
|---|---|---|---|
| Before puberty | High feeding level to increase growth rate | - Decreased pubertal mammary growth and reduced MY | - Johnsson (1988); Lammers et al. (1999); Radcliff et al. (2000); Sejrsen et al. (2000) |
| - No effect | - Van Amburgh et al. (1998), Daniels et al. (2009) | ||
| - Positive effects on mammary growth and subsequent MY | - Choi et al. (1997) | ||
| - Decreased mammary parenchymal mass, DNA content or both | - Petitclerc et al. (1984); Capuco et al. (1995); Davis Rincker et al. (2008) | ||
| - Decreased mammary parenchyma cell numbers | - Meyer et al. (2006a) | ||
| - No influence on mammary epithelial cells proliferation, rate of parenchyma DNA accretion and the total DNA | - Meyer et al. (2006b) | ||
| 6 wks of age until 300 kg BW | 3 different dairy breeds with 3 different energy rations of 3 different energy density for ad libitum intake to support 3 levels of daily gain | Lowest MY was noted in groups fed at feeding levels to gain BW above 350, 550, and 650 g/d, in Jersey, Danish Reds, and Friesians, respectively | Hohenboken et al. (1995) |
| 5 to 10 months of age | Diet 1: CP 142 g/kg DM with high rumen undegradable protein (RUP) (270 g RUP/kg CP), diet 2: high CP (183 g CP/kg DM) with low RUP (133 g RUP/kg CP), diet 3: high CP (182 g CP/kg DM) with high RUP (267 g RUP/kg CP). Energy in diet was 11 MJ ME/kg DM. | Low CP fed group had lowest weight gain (918 g/d) than other 2 groups (952 and 990 g, respectively), at pre-pubertal level. Daily first lactation milk, protein and fat yields were not affected. Diets with high RUP with 182 g CP per kg DM produced 0.08 kg more milk daily protein. | Dobos et al. (2000) |
| Before puberty (trial 1) and after puberty (trial 2) | Fed diets to achieve moderate (0.7 kg/d BW gain) or accelerated gains (0.9 kg BW gain). During study, half of the heifers were mated at first oestrus after 370 kg BW and the rest after 420 kg of BW | BW gains affected the body condition in post-pubertal stage. No effect on first lactation performance, accelerated BW gains after puberty influenced milk fat content. Early calving negatively influenced MY | Abeni et al. (2000) |
| 200 to 300 d of age | Bovine somatotropin (bST) and RUP during early post weaning period until just prior to puberty | Increase in BW and skeletal growth without reducing age at puberty in bST and RUP fed animals | Moallem et al. (2004a) |