Effects of environmental factors on growth traits in Makuie sheep

The Makuie sheep is a fat-tailed sheep breed which can be found in the Azerbaijan province of Iran. non- genetic parameters obtained from data collected from 1993 to 2012 Makuie sheep research station of West Azerbaijan province in Iran were evaluated in the present study. The non- genetic parameters for birth weight, weaning weight (3 months), 6-month, 9-month and yearling weight traits were estimated based on 19 years of data using SAS software. Least squares means were 4.11± 0.88, 21.50±3.50, 27.18±3.53, 28.57±4.44 and 34.21±3.88 kg for weight at birth, 3, 6, 9 and 12 month, respectively. The birth year had a significant effect on all traits while the effect of birth type significantly affected all traits (p<0.05). The lamb's sex had a significant effect on all traits (p<0.05). The effect of dam's age had a significant effect on all traits except 9- month (p<0.05). Results showed that non- genetic factors have an important role in expressing of genetic potential in the lambs

A note on divergent selection for total fleece weight in adult Angora rabbits: direct response to selection on total fleece weight at first and second harvest

[EN] In order to explore the genetic variability of wool production and other quantitative traits, an 8-cohort divergent selection experiment for total fleece weight (TFW) was carried out in French Angora rabbits. Studies were made on the wool production of a total of 669 female rabbits born between 1994 and 2001 and having produced wool from first to 12th harvests. The aim of the selection experiment was to obtain two divergent lines (low and high) on TFW. From preliminary analysis, the dataset was separated into three subsets according to the harvest number: one for each of the first two harvests and one for the third to the 12th harvests. In this paper, wool production data of the first and second harvests was analysed separately. Response to selection for total fleece weight at 3-12 harvest (TFW3-12) on this trait at first and second harvest was the aim of this paper. The second objective was to study the possibility of utilising values of the first or second harvest to estimate breeding values and as selection criteria for total fleece weight in the French Angora rabbit. Preliminary analysis of the data for non-genetic factors was done by the GLM procedure of SAS. Genetic parameters and breeding value estimates were carried out using a BLUP animal model using ASReml. A linear mixed model for a bivariate analysis of total fleece weight at first or second harvest and TFW3-12 was used. Heritability estimates of total fleece weight at first and second harvests were 0.36 and 0.38, respectively, and were similar to that observed at later harvests (0.35). The genetic correlation between TFW3-12 and fleece weight at first harvest was close to zero indicating that wool production at first harvest is a different trait from that of subsequent harvests. Genetic correlation estimates observed at second harvest were high (0.76) and response to selection at second harvest was similar to that observed for TFW3-12. These observations confirm that total fleece weight at first harvest is a different trait from TFW3-12. In French Angora rabbits, the high genetic correlation between TFW3-12 and total fleece weight at second harvest suggests the possibility of selection at this time for TFW3-12.The authors thank Gérard Auvinet, Jean Claude Musseau and Patricia Bayle of the Institut National de la Recherche Agronomique (INRA), Génétique Expérimentale en Productions Animales, Le Magneraud Poitou-Charentes Research Centre for the collection of data and the supply and care of Angora rabbits.Rafat, S.; Thébault, R.; Bonnet, M.; Deretz, S.; Pena-Arnaud, B.; De Rochambeau, H.; Allain, D. (2009). A note on divergent selection for total fleece weight in adult Angora rabbits: direct response to selection on total fleece weight at first and second harvest. World Rabbit Science. 17(1):39-44. doi:10.4995/wrs.2009.669394417

Isolation and proliferation of spermatogonial cells from ghezel sheep

Background: Sheep industry has taken steps toward transforming itself into a more efficient and competitive field. There are many varieties of sheep breeds in the world that each of them serves a useful purpose in the economies of different civilizations. Ghezel sheep is one of the Iranian important breeds that are raised for meat, milk and wool. Field of spermatogonial cell technologies provides tools for genetic improvement of sheep herd and multiple opportunities for research. Spermatogonial cells are the only stem cells capable of transmitting genetic information to future generations. Methods: This study was designed to extend the technique of isolation and in vitro proliferation of spermatogonial cells in Ghezel sheep. Results: Isolated cells were characterized further by using specific markers for type A spermatogonia, including PLZF. Also, sertoli cells were characterized by vimentin which is a specific marker for sertoli cells. After 10 days of co-culture, viability rates of the cells was above 94.7, but after the freezing process the viability rates were 74 percent. Conclusion: In this study, a standard method for isolation and in vitro proliferation of spermatogonial stem cells in Ghezel sheep was developed. © 2018, Avicenna Journal of Medical Biotechnology. All rights reserved

Isolation and proliferation of spermatogonial cells from ghezel sheep

Background: Sheep industry has taken steps toward transforming itself into a more efficient and competitive field. There are many varieties of sheep breeds in the world that each of them serves a useful purpose in the economies of different civilizations. Ghezel sheep is one of the Iranian important breeds that are raised for meat, milk and wool. Field of spermatogonial cell technologies provides tools for genetic improvement of sheep herd and multiple opportunities for research. Spermatogonial cells are the only stem cells capable of transmitting genetic information to future generations. Methods: This study was designed to extend the technique of isolation and in vitro proliferation of spermatogonial cells in Ghezel sheep. Results: Isolated cells were characterized further by using specific markers for type A spermatogonia, including PLZF. Also, sertoli cells were characterized by vimentin which is a specific marker for sertoli cells. After 10 days of co-culture, viability rates of the cells was above 94.7, but after the freezing process the viability rates were 74 percent. Conclusion: In this study, a standard method for isolation and in vitro proliferation of spermatogonial stem cells in Ghezel sheep was developed. © 2018, Avicenna Journal of Medical Biotechnology. All rights reserved

Evaluation of the relationship between some blood metabolites and elements on the ovarian persistent follicle formation in dairy cattle

The object of this study was to investigate the effect of some blood metabolites and elements on the ovarian persistent follicle formation in dairy cattle. Blood samples were obtained from 117 lactating cows in two groups of normal and persistent follicle status. Glucose, urea, total protein, phosphorus and betahydroxy butyrate were measured by spectrophotometer method. Estradiol concentration in blood serum was measured by ELISA method. Effects of calving season, parity and milk production at 50-60 days postpartum were studied on persistent follicle status. Status of animal (presence or absence of resistant follicle) had significant effect on urea, protein, beta-hydroxybutyrate, phosphorus and estradiol (

Estimates of the genetic parameters of turkey body weight using random regression analysis

International audienceRandom regression (RR) analysis has been recommended to estimate the genetic parameters of longitudinal data. The objective of this study was to evaluate the growth of turkeys using RR models. Data were collected from 957 turkeys and included 15 478 individual body weight recorded during the first week of life and between weeks 2 and 32 by 2-week intervals. To take into account the repeated measurements of weight for each animal, a specific overall growth curve was modelled using a cubic smoothing spline. Animal deviation to this curve was also modelled using an RR function. All data were analysed with the ASReml package. The results showed an increase in heritability estimates over the trajectory and peaked at 0.60 around 20 to 32 weeks of age. Genetic correlations showed that turkeys could be selected at earlier time points, at 12 weeks of age, in order to increase the growth rate. In general, genetic correlation estimates were higher among adjacent ages, decreasing markedly with the increase of distance between ages. Negative genetic correlations were observed between ages

Effects of Marker Density, Number of Quantitative Trait Loci and Heritability of Trait on Genomic Selection Accuracy

The success of genomic selection mainly depends on the extent of linkage disequilibrium (LD) between markers and quantitative trait loci (QTL), number of QTL and heritability (h2) of the traits. The extent of LD depends on the genetic structure of the population and marker density. This study was conducted to determine the effects of marker density, level of heritability, number of QTL, and to compare the accuracy of predicting breeding values using two diverse approaches: GBLUP and BayesA using simulated data under two different distributions of the QTL effect. Thereby, three traits (milk production, carcass weight and mature body weight) were simulated with the heritability of 0.10, 0.30 and 0.50, respectively; for each ovine animal, a genome with three chromosomes, 100 cM each. Three different marker densities was considered (1000, 2000 and 3000 markers) and the number of QTL was assumed to be either 100, 200 or 300. Data were simulated with two different distributions of the QTL effect which were uniform and gamma (α=1.66 and β=0.4) the marker density, number of the QTL, the QTL effect distributions and heritability levels significantly affected the accuracy of genomic breeding values (P<0.05). The BayesA produced estimates with greater accuracies in traits influenced by a low number of the QTL and with the gamma QTL effects distribution. Based on the findings of this simulation, heritability, as well as dense marker panels, aiming to increase the level of LD between the markers and QTL, is likely to be needed for successful implementation of the genomic selection