Inheritance of racing performance of trotter horses: An overview

Harness racing is a form of horseracing in which the horses race in a specified gait (trot or pace). In contrast to the Thoroughbred, the trotter is not an international breed. In this type, the horses are raced with trotting or pacing gait. Breeds specialized for racing at trot or pace are indigenous to many countries. Separate breeds of light harness horses, generally designated as trotters have evolved for racing purposes in several countries. The important horse breeds used for harness racing in different parts of the world are the Standardbred, French Trotter, Swedish Trotter, Orlov Trotter, Russian Trotter, Finnhorse, Icelandic Toelter, Dole horse and North-Swedish cold-blooded horses. The trotter ranks worldwide second to the Thoroughbred in popularity as a racehorse. Racing performance in trotters, in contrast to Thoroughbred is characterized by qualifying tests before entering the races, inclusion of more than one breed in international races only and greater duration of racing career. An intensive selection of stallions on the basis of phenotypic racing performance has been practised in many trotter populations for quite a long time. Unlike Thoroughbreds, improvements have been observed in different trotter populations and this is attributed to both genetic and environmental changes. Environmental changes include enhanced training methods, as well as improved tracks, harness and sulkies. As a result of selection, racing time of trotters has been reduced over the years. The estimated annual genetic progress in racing performance traits of Swedish Standardbred horses corresponds to 5% of the phenotypic standard deviation, 3.6% in French Trotters and 5% in Dutch Trotters. According to the recent selection for speed in trot, this trait remains heritable and genetic improvement is observed in most countries. Correlations between earnings and times are negative and high, and hence favourable. As a result, selection based on times and earnings are quite effective. A multiple trait approach avoids potential biases of one particular measure, even if the objective of all traits is much the same. Since racing performance may be evaluated in both males and females and repeated observations can be obtained on the same animal, mass selection based on performance tests would be the selection procedure of choice. In the future, interest in the possible use of marker-assisted selection (MAS) for enhanced genetic improvement in horses is likely to increase. MAS is likely to be a valuable complement to selection of horses based on estimated breeding values (EBVs) obtained by the Best Linear Unbiased Prediction (BLUP) method, rather than as a replacement for EBVs.     

Estimates of non-genetic effects and genetic parameters for body measures and subjectively scored traits in Finnhorse trotters

This study examined non-genetic effects and genetic parameters of body measures and subjectively scored traits in the Finnhorse trotter population. The data was based on studbook inspections from 1971 to 2004 covering observations on 6381 horses. There were five body measures – height at withers, height at croup, circumference of girth, length of body and circumference of cannon bone – and six subjectively scored traits – character, body conformation, leg stances, quality of legs, hooves and movements – included in the analyses. Multivariate mixed models were applied with year–sex and age as fixed effects and animal as a random effect. The year–sex effect had a significant influence on body measures and scored traits. Age at judging had a significant influence on all traits but height at withers and body conformation. Heritability estimates were from 0.53 to 0.78 for body measures and 0.10 to 0.19 for scored traits. Genetic correlations between body measures were highly positive, from 0.75 to 0.98, whilst genetic correlations between scored traits varied between − 0.20 and 0.51. Genetic correlations between body measures and scored traits were mainly negative, from − 0.38 to 0.09. Our results indicate that additive genetic effects are relevant determinants for body measures of Finnhorse trotters. The scored traits were of low to moderate heritability and were relevantly influenced by environmental effects.     

Teff (Eragrostis tef) production constraints on Vertisols in Ethiopia: farmers' perceptions and evaluation of low soil zinc as yield-limiting factor

Thirty samples of grassland surface soil, which had a diverse management history and consequently displayed a wide range of soil properties, were studied to analyze the relationships between soil microbial activity and soil properties. The microbial measurements included the number of bacteria, number of Gram negative bacteria, number of fungi obtained by the plate method, TTC reducing activity and nitrifying activity. In the uppermost layers (at the 0 to 2 cm depth), Simple correlation analyses showed that bacterial numbers were positively correlated with soil pH and negatively correlated with Bray No. 2 P, total C, and grassland age. TTC reducing activity and nitrifying activity were also positively correlated with soil pH, while the fungal number was not significantly related to any soil properties. In the lower layer (at the 5 to 15 cm depth), all of the microbial measurements were negatively correlated with grassland age and were positively correlated with microbial substrate level. soil pH and exchangeable K were positively correlated with the microbial measurements except for the Gram negative bacteria, and significant correlations among almost all the microbial measurements were observed. These results suggest that soli pH accounted primarily for microbial activities in the uppermost layers. Also microbial substrate level, soil pH and probably amounts of exchangeable K, which inevitably decreased with grassland age, appeared to control the microbial activities in the lower soil layers.     

Biokinematics under Competitive Racing Conditions in Young Standardbred Trotters: A Preliminary Report

With the aim of evaluating equine performance in competitive trotter horses under normal racing conditions data of stride length, stride frequency and mean horses speed were obtained from 50, 2-year-old Italian winner fillies during the racing and the sprint laps of competition. The enhancement of speed in the sprint lap was obtained by increasing both stride length and stride frequency. Stride frequency for the racing and the sprint laps were (mean ± SD) 133.63 ± 3.93 and 138.97 ± 6.62 strides per minute, respectively and Stride length for the racing and the sprint laps were 7.17 ± 0.17 and 7.30 ± 0.11 m, respectively; mean speed was 48.18 ± 1.09 km/hr. The usefulness of the kinematic assessments is discussed as is its potential reference for future indicators of performance.     

Biokinematics Under Competitive Racing Conditions in Young Standardbred Trotter Horses: A Preliminary Report

The aim of this study was to evaluate equine performance in competitive trotter horses under normal racing conditions. Data of stride length, stride frequency, and mean horse speed were obtained from 50 2-year-old Italian fillies that were winners during the racing and the sprint laps of competition. The enhancement of speed in the sprint lap was obtained by increasing both stride length and stride frequency. Stride frequencies for the racing and the sprint laps were (mean ± SD) 133.63 ± 3.93 and 138.97 ± 6.62 strides per minute, respectively, and stride lengths for the racing and the sprint laps were 7.17 ± 0.17 and 7.30 ± 0.11 m, respectively; mean speed was 48.18 ± 1.09. The usefulness of the kinematic assessments as well as its potential reference for future indicators of performance is discussed in this study.     

Phosphorus Response Studies on Some Varieties of Durum Wheat (Triticum durum Desf.) and Tef (Eragrostis tef (Zucc.) Trotter) Grown in Sand Culture

The response of four varieties each of durum wheat (DZ-04-118, DZ-320, DZ-918 and TOB-2) and tef (DZ-01-354, DZ-01-787, DZ-01-1445, and DZ-Cr-37) to P application levels was examined in a sand culture study conducted in a glasshouse for 4 weeks. Results showed that plant height, shoot and root dry weights, and plant P uptake were increased by increasing levels of P application from 0 to 5 (tef) and 0 to 10 mg P 100 g⁻¹ (wheat). Varietal differences were also observed in all parameters, except in shoot dry weight of the four durum wheat varieties. In general, all modern varieties of the two crops showed better growth and P uptake than the corresponding traditional varieties. The short period study proved that variations generally existed in the P responses of durum wheat and tef varieties which may be confirmed by long-term study up to maturity. Inclusion of more populations in similar studies may help to identify P efficient genotypes.