Data from 113 Dutch organic farms were analysed to determine the effect of cross-breeding on production and functional traits. In total, data on 33 788 lactations between January 2003 and February 2009 from 15 015 cows were available. Holstein-Friesian pure-bred cows produced most kg of milk in 305 days, but with the lowest percentages of fat and protein of all pure-bred cows in the data set. Cross-breeding Holstein dairy cows with other breeds (Brown Swiss, Dutch Friesian, Groningen White Headed, Jersey, Meuse Rhine Yssel, Montbé liarde or Fleckvieh) decreased milk production, but improved fertility and udder health in most crossbred animals. In most breeds, heterosis had a significant effect (P , 0.05) on milk (kg in 305 days), fat and protein-corrected milk production (kg in 305 days) and calving interval (CI) in the favourable direction (i.e. more milk, shorter CI), but unfavourably for somatic cell count (higher cell count). Recombination was unfavourable for the milk production traits, but favourable for the functional traits (fertility and udder health). Farm characteristics, like soil type or housing system, affected the regression coefficients on breed components significantly. The effect of the Holstein breed on milk yield was twice as large in cubicle housing as in other housing systems. Jerseys had a negative effect on fertility only on farms on sandy soils. Hence, breed effects differ across farming systems in the organic farming and farmers can use such information to dovetail their farming system with the type of cow they use.

No abstract

No abstract

No abstract

Organic matter (OM) digestibility of 53 feeds was estimated in horses, sheep and in vitro using rumen fluid. Feeds tested were: roughages (grass hay, fresh grass, wilted grass silage, forage maize and artificially dried roughage), compound feeds and compound feed ingredients including cereals. Technical merits of the chosen procedure for digestibility trials with horses are discussed. Horse digestibility data for forages were consistently lower than sheep data, with a variable fibre level effect. For compound feeds and compound feed ingredients horse digestibility was about comparable to sheep digestibility allowing for considerable differences between feeds. In vitro digestibility gave a reliable estimation of OM digestibility in horses for the different group of feeds. (Abstract retrieved from CAB Abstracts by CABI’s permission)