SUMMARY Two pairs of lines mice, selected for High and Low weight at 5 weeks age (H L ) 10 over 15 generations, were compared with each other an unselected control line (QC) three different ages, i.e. 5, 21 age. Differences in percentage fat between small weeks, clearcut the almost twice as ones. The H was slightly fatter than all ages two ages. developmental pattern deposition unaffected by selection high or low relationship carcass similar , QC lines. Selection affected level weights...

Animal mortality is indicative of animal health and welfare standards, which are growing concern to the agricultural industry. The objective present study was ascertain risk factors associated with at multiple life stages in pasture-based, seasonal-calving dairy beef herds. Males females were stratified into seven based on age (0 2 d, 3 7 8 30 31 182 183 365 366 730 731 1,095 d) whereas ≥1 calving event further five cow parity number (1, 2, 3, 4, 5). Mortality defined as whether an died...

A major use of genetic data is parentage verification and identification as inaccurate pedigrees negatively affect gain. Since 2012 the international standard for single nucleotide polymorphism (SNP) in Bos taurus cattle has been ISAG SNP panels. While these panels provide an increased level accuracy over microsatellite markers (MS), they can validate wrong parent at ≤1% misconcordance rate levels, indicating that more are needed if a accurate pedigree required. With rapidly increasing...

Twenty-four lines were bred from a base population of outbred Q mice by continued full-sib mating. Inbreeding depression in litter size at birth was observed. This decline analysed terms ovulation rate, the incidence preimplantation mortality and postimplantation mortality. Pregnant females dissected 17½ days' gestation numbers corpora lutea, or eggs, live dead embryos counted. Matings arranged so that separate estimates effects inbreeding mother on components could be obtained. In first...

SUMMARY Birth weight was recorded in the first and second litters of six inbred strains mice all possible crosses between them. The mean birth F 1 young significantly greater than that most cases; no case were they lighter at birth. Foetal placental on 17th day post coitum four two pairs reciprocal crosses. foetuses 13–16% heavier crossing strains. placentae about 15% three Crossbreeding did not affect fourth strain. significance these findings is discussed. Analyses data from individual...

The cumulative improvement achieved in the genetic merit for reproductive performance dairy populations will likely improve cow longevity; therefore, it is time to reassess whether linear type traits are still suitable predictors of survival an aging population. objective present study was therefore estimate correlations between and from one parity next and, doing so, evaluate if those change with advancing parity. After edits, 152,894 lactation records (first ninth parity) were available...

SUMMARY Mice were selected for high and low body weight at 5 10 weeks of age. Selection was performed (1) separately each trait, (2) various combinations the two traits, using ( a ) independent culling levels b restricted indices. Two-way selection trait gave large responses correlated responses. by intended to increase 5-week while restricting change in 10-week no demonstrable response; decrease resulted decreases weights both ages. Index selection, one age holding that other constant,...

The inclusion of reproductive performance in dairy cow breeding schemes has resulted a cumulative improvement genetic merit for performance; this should manifest longer productive lives through reduced requirement involuntary culling. Nonetheless, the average length life not changed most populations, suggesting that risk factors culling, especially older cows, are possibly more associated with lower yield or high somatic cell score (SCS) than compromised performance. objective present study...

SUMMARY The effects of selection for increased or decreased body weight in mice, at 5 10 weeks age, on the fibre number, diameter and m. sternomastoideus anterior tibialis muscles were studied. Unselected control mice also included. Significant detected case each traits. However, magnitude any particular correlated response to varied between ages an unsystematic fashion. Most changes muscle resulting from attributable positively number but they accompanied by some cases. responses described...

SUMMARY The effects of selection for increased and decreased body weight in mice at 5 10 weeks age on the mean fibre diameter number seven different muscles were studied by dissecting histologically examining animals from large, small unselected control lines. purpose was to learn how size affects muscle its components. Selection significantly m. biceps brachii, tibialis anterior, pectoralis major, brachio-radialis, soleus, rectus femoris psoas major . These increases reflected both although...

Genetic selection for milking speed is feasible. The existence of a correlation structure between and milk yield, however, necessitates strategy to increase with no repercussion on genetic merit yield. Residual duration (RMD) residual including somatic cell score (RMDS), defined as the residuals from regression model yield or plus (SCS) have been advocated. objective this study was undertake first ever analysis these novel traits. Data electronically recorded other characteristics 235 005...

Summary. A summary of several estimates the partial regressions foetal weight and placental at 17½ days gestation on (i) number implants in a uterine horn (ii) whole litter is presented for litters one outbred stock four highly inbred lines mice. These suggest that effects size are similar different but (a) systemic effect growth (b) local different, least until 17th day gestation, stock.

The objective was to explore if the regression of phenotypic performance for six milk production traits on respective estimate genetic merit that trait differed by herd milking frequency; variance components each in two frequency environments were also estimated as well correlation between same both environments. data used included 12,581 lactations from 5,456 cows 32 spring-calving once-a-day (OAD) herds. Each OAD matched with three contemporary twice-a-day (TAD)-milking herds; 35,823...

Summary. Analyses of recorded data showed that fewer young were born in second litters than first JU/Fa mice and the reduction size occurred only when lactation was concurrent with gestation. The effect on prenatal mortality pregnancies experimentally tested. 46% lactating females 7% non-lactating females, mated post-partum oestrus, lost whole litters. Dissections pregnant caused a significant decrease number live embryos. This consequence extremely high post-implantation mortality—48·3%...

ABSTRACT The growth of adipose tissue was investigated in lines mice selected for high and low body weight at 5 10 weeks age, by dissecting weighing individual fat depots from aged 5, 7·5, 15 weeks. At fixed ages most were heavier the High lighter Low lines. Depots grew different rates rate total deposition relative to gain greater than about 20g live had similar proportions fat; lower weights relatively leaner. These correlated effects selection more pronounced faster growing kidneys...

Summary M. biceps brachii and m. tibialis anterior were studied at a fixed body weight in mice selected for high low age. Muscle weights approximately equal the two lines. In general, muscles from high-line appeared to contain larger number of smaller fibres than low-line which there fewer but wider unselected control population lines derived.