Rearing conditions and lifetime milk revenues in Swedish dairy cows

Impacts of Prepubertal Rearing Intensity and Calf Health on First-Lactation Yield and Lifetime Performance

The objective of the present study was to investigate possible long-term effects of calf and heifer feeding intensity on first-lactation milk yield and lifetime efficiency (milk per day of life). Detailed records from a total number of 2,252 female German Holstein calves from one commercial farm were obtained from birth to culling. Data regarding all information about calf’s birth, rearing time until first insemination, first calving, first-lactation yield and lifetime performance were collected over a 12-year period. This large data volume was merged, handled, checked for plausibility, classified and evaluated. Analyses revealed that body weight at an age of six months was significantly influenced by the average daily gain in the first two weeks of life (P<0.0001) and by the duration of treatment for respiratory diseases (P=0.0080). Moreover, first-lactation yield was affected by average daily gain in the whole first year of life (P=0.0013) and particularly in the period of month nine to twelve (P=0.00187). Lifetime efficiency was significantly influenced by body weight at first insemination (P=0.0051), average milk yield (P<0.0001) and reason for culling (P<0.0001). The results of this long-term study confirm that growth is important in general, but as shown by the negative correlation between average daily gain from month nine to twelve and the first lactation milk yield, nutrient intake (energy and protein) should be adapted to enable a controlled growth especially at certain periods of life. After six months of age, daily gain has to be controlled to avoid fat accumulation for a healthy and effective start of lactation. In addition, this analysis revealed that after passing first lactation, particularly health and fertility are the keys for a long efficient lifetime of dairy cows.

Association between age at first calving, year and season of first calving and milk production in Holstein cows

The effects of first calving (FC) in Holstein heifers on their first lactation, second lactation and lifetime milk production were examined from an initial database of 459 743 animals that first calved between 1 January 1990 and 31 July 2010 in Wallonia, Belgium. The FC age class (18 to 22, 22 to 26, 26 to 30, 30 to 34, 34 to 38 and 38 to 42 months), the FC season and FC year class (1990 to 1994, 1995 to 1999, 2000 to 2004 and 2005 to 2010) were considered when analysing the first and second lactation data. Lifetime data were similarly analysed, but did not include animals that calved after 2005 because many of them were still lactating. Only 24% of animals had their FC before 26 months of age. Animals that first calved between 22 and 26 months of age had more lactations and productive days during their life. They also had higher first and second lactation milk production and lifetime milk production. Summer or autumn FC improved first lactation, second lactation and lifetime milk production, as well as production per day of lactation, compared with winter or spring FC. Compared with animals that calved for the first time in 1990 to 1994, animals with a FC in 2000 to 2004 had a longer calving interval (0.5 months), fewer lactations per animal (-0.6) and fewer days in their lifetime lactation (a reduction of 144 days). As a result, the animals' lifetime production did not increase between 1990 to 1994 and 2000 to 2004, although milk production per day of lactation (22.85 v. 20.49 l/day) and per day of life (11.49 v. 10.78 l/day) improved. Milk fat content was lower in 2000 to 2004 than in 1990 to 1994, but protein content remained relatively constant, probably because of the cows' higher production level and increased dietary concentrate supplementation.