Summary In mammals, between‐species correlation between mature size and maturing rate is high. The within‐species relationship is not so clear. An experiment with 167 mice of small RoC57BL/6 and large RoNMRI lines was set up, to study the influence of animal mature size on maturing rate. The body mass of animals was measured every 3 days, between the ages 12 and 120 days. Individual ages at half the adulthood and at adulthood were determined on the basis of logistic growth curves. Three linear statistical models based on an allometric equation were used to test between‐line, between‐sex‐line, and between‐family maturing rates. Growth rate and maturing rate are within the species significantly affected by mature size. At mature size, the smaller RoC57BL/6 mice were older than the larger RoNMRI mice. In the model with the significant effects line, sex and family included, the same allometric coefficient was positive. The model which includes an allometric equation within line and sex was no better fitting than the previous model. Not all the estimates of allometric coefficients were within expected ranges, but standard errors were relatively high. Because significant effects are partly of genetic origin and standard errors are high, the selection for higher maturing rate might be possible without changes in mature size. No method for determining degree of maturity during growth has been found so far, therefore the selection would be relatively slow, due to the extension of generation interval. Zusammenfassung Adulte Größe und Wachstumsrate von RoC57BL/6 und RoNMRI Mäusen In Säugern ist die korrelazion zwischen adulter Größe und Wachstumstrate hoch, aber innerartlich ist diese Beziehung nicht so klar. In einem Versuch mit 167 Mäusen der kleinen RoC57BL/6 und der großen RoNMRI Linien wurde der Einfluß adulter Größe auf Wachstumstrate untersucht. Körpermasse wurde zwischen Altern von 12 und 120 Tagen alle 3 Tage erhoben. Alter bei halber und voller adulter große wurde mittels logistischer Wachstumskurven geschätzt. Drei lineare statistische Modelle auf der Basis logistischer kurven wurden verwendet zur Schätzung von Wachstumsraten für Linien, Geschlects‐Linien Gruppen und von Familien. Wachstums und Reifungsraten innerhalb Arten werden signifikant von adulter Größe beeinflußt. Die Mäusen der kleineren Linie waren bei Erreichen des adulten Gewichtes älter als jene der größeren. In Modellen mit den signifikanten Wirkungen von Linien, Geschlecht und Familien war derselbe Allometriekoeffizient positiv, aber im Modell mit Linien‐ und Geschlechtsspezifischen Allometriegliechungen war die Anpassung nicht besser. Nicht alle Schätzwerte der Allometriekoeffizienten waren innerhalb des Erwartdsungbereiches, doch waren die Standardfehler hoch. Da die Einflußfaktoren zum Teil genetischen Ursprungs sind Standardfehler hoch, sollte Selektion auf Wachstumstrate ohne Änderung der adulten Größe möglich sein. Allerdings ist keine Methode zur Schätzung der Reife währen des Wachstums bekannt, sodaß solche Selektion aufgrund verlängerter G...
The effect of crossing of Black and White (BW) cows with Charolais (CHA), Limousin (LIM) and Belgian Blue (BB) sires on carcass traits of their crossbred male offspring was evaluated. The crossbred bulls were compared with pure breed BW, CHA and LIM bulls. Bulls younger than 24 months and slaughtered in Slovenian slaughterhouses from 2005 to 2008 were included in the comparison. All crossbred genotypes had heavier carcass weight and better net daily gain than pure breed BW bulls. Within crossbred groups the CHAxBW bulls had the heaviest carcasses and the greatest net daily gain. Among all genotypes the best carcass conformation had CHA and the worst BW bulls. In the comparison to pure breeds the BBxBW bulls had for 1.1 of the class better conformation than BW and for 0.5 worse than CHA bulls. Within crossbreeds the BBxBW bulls had for 0.12 and 0.30 of the class better conformation than CHAxBW and LIMxBW bulls. Carcass fatness varied from 2.3 to 2.6 among genotypes, where the BBxBW buls had the lowest fatness score
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.