Estimation of genetic parameters for young stock survival in beef x dairy crossbred calves

Young stock survival is a trait of crucial importance in cattle breeding as calf mortality leads to economic losses and represents an animal welfare issue. The aim of this study was to estimate genetic parameters and sire breeding values for young stock survival in beef x dairy crossbred calves. Two traits were analysed with a univariate animal model: young stock survival between 1 to 30 days and 31 to 200 days after birth. Breed combinations with Belgian Blue sires outperformed all other sire breeds. The lowest survival rates were found for breed combinations with Jersey dams or Blonde d’Aquitaine sires. The results showed low but significant heritabilities (0.045 to 0.075) for both survival traits. Differences in breeding values between sires ranged from −2.5% to 3.5% and from −5.4% to 4.7% survival from 1 to 30 days and 31 to 200 days, respectively. Based on these findings, we concluded that it is feasible to breed for improved young stock survival in beef x dairy crossbred calves. This will hopefully contribute to increasing the survival rate of the calves and reduce economic losses for the farmers.     

Further results on the survival of a gene represented in a founder population

This paper is concerned with gene survival in a population which may increase without density dependence according to a generalization of the Moran model for haploid individuals. A selective advantage to one allele and the possibility of differential reproductive rates are allowed. Simple conditions are given for ultimate homozygosity to be certain and for the possibility of ultimate polymorphism. The results complement and extend those of Heyde (1981, 1982).     

Oxygen transfer deficiencies in starch-based media

Insufficient oxygen transfer in a highly viscous media with varying viscosity occurs during the degradation of starch byBacillus licheniformis. Oxygen transfer rate (OTR) decreased below 0.3 gl^–1 h^–1 for viscosities above 5 to 10 mPa.s and agitation speeds lower than 710 rev/min. Increasing agitation speeds by 30 to 50% compensated for the decrease in OTR for viscosities between 10 and 200 mPa.s. A dual impeller is considered essential for growth improvement.     

Song and immunological condition in male barn swallows (Hirundo rustica)

Male secondary sexual characters may have evolved as intra-or intersexual signals of male phenotypic or genetic quality.In birds, singing performance may have the function to honestlyreveal health and vigor of individual males. Infectious diseasesand poor body conditions would therefore be expected to negativelyinfluence singing performance. Since bird pathogens are knownto elicit both a humoral and a cell-mediated immune response,it can be predicted that a negative relationship exists betweensinging performance and activity of the immune system. Thisprediction was tested for the first time in this correlationalstudy. The relationships between song rate and features andhematological variables (concentration of leukocytes in peripheralblood, ratio of gamma-globulins to total plasma proteins, bloodcell sedimentation rate, hematocrit) and body condition wereanalyzed in a population of bam swallows (Hirundo rustica).Song rate was negatively correlated with lymphocyte concentrationand with the ratio of gamma-globulins to plasma proteins. Spectrographicanalysis showed that features of song were not significantlycorrelated with hematological variables or body condition. Thelevel of circulating testosterone was not correlated with songrate nor hematological variables. This study is the first toshow a correlation between a bird's singing performance andhematological profile and suggests that song rate of male barnswallows may reflect their health status. Song in this speciesmight thus have evolved because it allows prospecting femalesto assess aspects of phenotypic and/or genetic quality of potentialmates     

Demographic analysis of insect reproductive levels, patterns and heterogeneity: case study of laboratory strains of three Hawaiian tephritids

Reproductive data were collected on individually-held adult oriental fruit flies, Dacus dorsalis, melon flies, Dacus cucurbitae, and Mediterranean fruit flies, Ceratitis capitata including age-by-parity relations, birth interval, frequency distribution of individual egg production levels and the concentration of reproduction among females in a cohort. Specific findings include: i) delay in reproductive peaks in a cohort after eclosion is due almost entirely to the variance in attainment of reproductive maturity among individuals; ii) low reproductive output of reproductively mature melon flies is due mostly to long birth intervals; iii) high egg production in both the medfly and the oriental fruit fly is due to their consistency of egg laying levels and frequency (short birth intervals). Discussion stresses the importance of viewing reproduction, not as a singular and discrete life history trait, but as consisting of subcomponents of daily parity, cumulative parity and birth interval.

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Résumé Les informations sur la reproduction ont été obtenues à partir d'adultes de Dacus dorsalis, D. cucurbitae, C. capitata, élevés individuellement. Elles portent sur les paramètres suivants: distribution par âge en fonction de la fécondité, échelonnement des pontes, distribution des niveaux quotidiens de ponte, fréquence des pondeuses par cohorte.Différents caractères spécifiques ont été mis en évidence: 1) La variabilité de la date d'apparition de la maturité reproductive est pour l'essentiel responsable du retard dans les dates de reproduction maximale; 2) De 30 à 50% des femelles de D. dorsalis âgées de 10 jours pondent plus de 50 oeufs/jour pendant les deux semaines qui suivent, tandis que seulement 10 à 20% des femelles des deux autres espèces parviennent à pondre cette quantité d'oeufs à n'importe quel âge; 3) D. cucurbitae ayant atteint sa maturité pond environ pendant 40% des jours (c.à.d. chaque 2,5 j), tandis que les deux autres espèces pondent au moins quelques oeufs pendant 80% des jours (c.à.d. chaque 1,25 j); 4) La production élevée d'oeufs de C. capitata et de D. dorsalis est due à la régularité de leur niveau de ponte et à la fréquence (faible espacement); 5) Les fractions des effectifs qui ont pondu au moins 600 oeufs en 30 jours étaient approximativement de 0,8, 0,7, et 0,4 pour D. dorsalis, C. capitata, D. cucurbitae; 6) 50% des femelles de chacune des trois espèces contribuent en gros pour 65% à la ponte.

     

A rapid altitudinal range expansion in the pine processionary moth produced by the 2003 climatic anomaly

Climatic anomalies may produce, or accelerate, geographic range expansions of species limited by temperature or other climatic variables. Most such expansions are only temporary, before the prevailing climatic conditions drive the founder populations extinct. In contrast, here, we report a recent rapid shift of the range limit during the record hot summer of 2003 in southern Europe that has the potential to be both permanent, and to have important implications on species range dynamics in general. The winter pine processionary moth (Thaumetopoea pityocampa), an important pine defoliator whose larvae feed in colonies during the winter, is limited in its distribution by winter temperatures. In the last three decades, warmer winters have led to a gradual but substantial expansion of its range both latitudinally and altitudinally. In the summer of 2003, T. pityocampa underwent an extraordinary expansion to high elevation pine stands in the Italian Alps; its altitudinal range limit increased by one third of the total altitudinal expansion over the previous three decades. In an experiment, we found flight activity of newly emerged females to increase with temperature. By determining a threshold temperature for flight take‐offs under controlled conditions, we calculated that the nights above the threshold temperature were over five times more frequent, and considerably warmer, at the range limit in 2003 than in an average year. We therefore attribute the colonization of extreme, high‐elevation sites to increased nocturnal dispersal of females during the unusually warm night temperatures in June – August 2003. Importantly, the colonies established at extreme sites survived the winter and produced offspring in 2004, although the range did not expand further because of low night temperatures that year. We discuss several life‐history characteristics of T. pityocampa that maximize the likelihood of population persistence at the new range limit. As global warming continues and climatic anomalies are predicted to become more frequent, our results draw attention to the importance of extreme climatic events in the range formation of phytophagous insects.