In the latest edition of NRC (2007) the feeding recommendations for Ca and P to growing horses were increased with 35 and 25 %, respectively, based on results from a Canadian study showing that daily endogenous fecal losses of Ca and P were greater than previously suggested. A Ca absorption efficiency of 50 % is used for all horses. However, the true absorption efficiency might be as high as 70 % in young horses. P absorption efficiency is assumed to be higher for growing horses because their diets are often supplemented with inorganic P. Thus, an efficiency of 45 % is used for growing horses as compared to 35 % for mature horses.

I Sverige och övriga världen ses en ökad resistensutveckling mot anthelmintika hos ett flertal parasiter. Spolmasken, Parascaris equorum, är en av hästens vanligaste parasiter. För diagnos av läkemedelsresistens hos hästens spolmask används idag FECRT-metoden (faecal egg count reduction test). Detta trots att metoden varken är utvecklad eller validerad för detta ändamål. Det finns dock ingen annan metod att tillgå.

Retrospective data from two stud farms, in this study named stud farm A and B, including 742 mares, was statistically analysed. Parameters included in the analysis were type of insemination, date of the first insemination, number of inseminations, the age of the mares, if the mares had a foal or not, foaling date, result of pregnancy examination (if it was done), twin pregnancy and treatments given to the mares. The pregnancy results and the treatments where compiled into a number of frequency tables in which the mares where arranged according to age, month of first insemination, foal or not and type of insemination. There was a significant difference in pregnancy result between the years at both stud farms (2001 better than 2002). At stud farm A, in year 2001, month (at start of insemination) significantly influenced the pregnancy result.