Estimation of genetic parameters for racing performances in German trotters after consideration of individual races.
INTRODUCTION The estimation of breeding values of German trotters has changed last year from BLUP sire model using traits such as average racing time per year and money earnings per year (Katona and Distl, 1989; Schmitt, 1996) to a multiple trait BLUP animal model which utilises individual race results for the traits rank at finish, racing time and earnings (Röhe et al., 2001). In several genetic evaluation procedures in Europe annual records of racing perfomances are used for estimation of breeding values (e. g. Langlois et al., 1997; Arnason, 1999). The main disadvantage of using annual records is that all available information, for example level of a race, driver, starting lane or race track, cannot be considered because they change from race to race. The environmental effects can be estimated much more accurately by using individual race results. That means, track conditions at each single record can be estimated directly and no pre-adjustment of records for these effects are necessary. Also, the effect of every single race can be estimated when using individual records of trotters. The genetic-statistical model of Röhe et al. (2001) included only the effect race track. In order to avoid possible bias it would be better to consider the effect of every single race instead of the effect race track. The inclusion of the race effect may also improve the genetic-statistical estimation for the trait rank at finish. The objectives of this study were (1) creation of a more appropriate genetic statistical model for evaluation of breeding values, (2) comparison of two different genetic statistical models regarding the individual race effect as fixed as well as ignoring this effect and (3) estimation of genetic parameters for the German trotter population using the most appropriate multiple-trait genetic model.
Agricultural and Food Science in Finland
A study was carried out to examine the effect of ammonium ferric hexacyanoferrate (AFCF) on the transfer of radiocaesium from grass silage to the tissues of male lambs. During ensiling, a formic acid based additive and AFCF were sprayed on grass contaminated with Cs and the mixture was allowed to incubate for 45 days. A dose of 21 mg AFCF d, fed to sheep offered contaminated silage for fourteen days, reduced Cs transfer to muscle by 45% compared to that of control sheep. An equivalent dose of AFCF administered in a capsule reduced transfer by only 3%. In another experiment, AFCF intake of 50, 100 and 150 mg d for ten days reduced Cs transfer to sheep muscle by 75, 82 and 86%, respectively. In control lambs, of average live weight 38 and 47 kg, the feed to muscle Cs transfer coefficient averaged 0.15 d kg, but equilibrium between tissue and feed Cs had probably not been reached due to the short feeding period. Increasing doses of AFCF from 0 to 150 mg d increased the faecal/urinary Cs ratio from 2 to 42.
Application of resource allocation optimisation to provide profitable options for dairy production systems
A linear program (LP) model analysed resource use on a 100 ha dairy farm. A single optimum-profit combination was established for resources which were either optimised or constrained. It was found that, with a fixed herd of 320 milking cows, when production increased from 305 kg milksolids per cow (kg MS/cow) to 415 kg MS/cow, cash profit increased by 65%. This required additional supplements. If, however, feed demand and supply were optimised at 415 kg MS/cow, the LP reduced milking cow number rather than buy in feed to meet the increased feed demand from higher production per cow. At all production levels chosen between 305 and 415 kgMS/cow, it was most economic to dry off and cull cows early in dry summers to optimise feed demand vs. feed grown; use nitrogen (N) fertiliser to avoid a feed deficit only when response rates of better than 10 kgDM to 1 kg N could be expected; not use N for growing supplements to harvest. Pasture cover, within defined constraint levels, provided a buffer for feed demand and supply fluctuations. The study highlights the importance of assessing production, income and cost in an integrated framework to identify the point at which individual resources become limiting.