ORIGINAL_ARTICLE
Evaluation of nutritional properties of alfalfa and sainfoin forages by gas production techniques
Two forage species alfalfa (Medicago sativa), and sainfoin (Onobrychis viciifolia Scop.), at two consecutive growing season (spring and summer), were studied for their chemical composition and in vitro gas production characteristics. Data on cumulative gas production (mL gas/g DM) were fitted to the non-sigmoidal model, and for evaluation of model, the concordance correlation coefficient (CCC) was used to assess the agreement between predicted and observed data. Chemical analysis showed that nutrient composition was affected by the forage type. Concentration of fiber components (NDF, ADF, cellulose and crude fiber) were higher in alfalfa compared to sainfoin (P < 0.05). Concentration of fiber components was higher in the first cut compared to the second cut (P < 0.05) in both forages, but cellulose content was not affected by the growing season (P > 0.05). The results showed that there is a great potential for improving the analytical capacity of the technique, by reducing the length of incubation from 48 to 24 h for studies on high quality forages. This study showed that 24 h incubation provided informative results with high reproducibility of the measurements, clear relationship and high correlations between different parameters and the relative feed value (RFV), and also reliable models for prediction of metabolizable energy with high values for the coefficients of determination. The results indicated that the logistic model can be used to describe the in vitro gas production kinetics (CCC = 0.992). It was concluded that, in addition to chemical analysis, the in vitro gas production is a useful and simple technique for determination of the relative feeding value of these forage species.
https://lst.uk.ac.ir/article_475_62ae0cd1190082e4637421dbcc959af0.pdf
2013-04-28
1
9
10.22103/jlst.2013.475
Alfalfa
sainfoin
gas production
logistic model
concordance correlation
A.
Moharrery
alimoh@mailcity.com
1
Animal Science Department, Agricultural College, Shahrekord University P.O. Box 115, Shahrekord, Iran
LEAD_AUTHOR
E.
Toghyani
2
Animal Science Department, Agricultural College, Shahrekord University P.O. Box 115, Shahrekord, Iran
AUTHOR
ORIGINAL_ARTICLE
In vitro determination of the characteristics of fresh and frozen-thawed alfalfa and ryegrass
Current ruminant feeding systems depend on knowledge of the composition of feeds and the rate and extent of degradation of feed organic matter (OM) and crude protein (CP) in the rumen. The effect of storage and preparation of samples on in vitro gas production and fermentation characteristics of two common forage species, namely alfalfa and ryegrass werestudied. Samples were prepared as fresh (F), frozen-thawed (FT) and FT + starch (FT+S) before in vitro evaluation. The fractional rate of loss of organic matter (OM) and the total N and total VFA production during 12h of incubation weresignificantly faster for alfalfa than for ryegrass. Model parameters describing changes in OM loss and total N appearance differed significantly between F samples and FT and FT+S samples; there was a significant interaction between forage species and preparation method for fractional degradation rate of total N. A significant interaction between forage species and preparation method at 6h incubation changed the rankings. The propionate:acetate ratios after 12h incubation were similar for alfalfa and ryegrass but were lower for F and FT samples than for FT+S samples. After 12h of incubation, alfalfa produced more gas, total VFA (mmol/g OM) and microbial crude protein (mg/g OM) than ryegrass, whereas F samples produced more fermentation products than FT and FT+S samples. In vitro degradation characteristics of forage samples were influenced by forage species, but also by sample preparation method; therefore, consistent use of one sample preparation method is recommended when comparing degradation characteristics of forage species in vitro.
https://lst.uk.ac.ir/article_476_47d1ddd77897a24b51defe94934064cc.pdf
2012-11-28
11
18
10.22103/jlst.2012.476
in vitro fermentation
forages
preparation method
fresh
frozen-thawed
R.
Tahmasbi
rtahmasb@uk.ac.ir
1
Department of Animal Science, Faculty of Agriculture, Shahid Bahonar University of Kerman, 76169-133, Kerman, Iran
LEAD_AUTHOR
R.C.
Dobos
2
NSW Department of Primary Industries, Beef Industry Centre of Excellence, Armidale, NSW 2351, Australia
AUTHOR
J.V.
Nolan
3
School of Environmental and Rural Sciences, University of New England, Armidale, NSW 2351, Australia
AUTHOR
ORIGINAL_ARTICLE
Effect of dietary energy level and docking on carcass characteristics of fat-tailed Kurdi sheep
Effects of partial docking on feedlot performance and body fat characteristics were studied in a fat-tailed sheep breed. Thirty-eight male lambs with an average weight of 4.44 ± 0.48 were randomly divided into two groups. The lambs in one group were partially docked at 3-4 h after birth, using rubber rings, and the lambs in another group remained intact (control). After weaning, 20 male lambs from each group were divided into two subgroups; one subgroup was fed with a normal dietary energy level (2.45 Mcal/kg ME) and the other subgroup received a high-energy diet (2.73 Mcal/kg ME) for 84 days. The lambs were fed individually. At the end of the fattening period, the lambs were slaughtered for determination of carcass characteristics. Warm carcass weight (WCW) and fat depth at the12th rib was recorded. At 24 h postmortem, samples of omental fat (for chemical analysis), and caudal fat were taken from chilled (4°C) carcasses for the determination of fatty acid (FA) composition. No significant difference was observed for the weight gain between docked and control lambs during the suckling period. During the fattening period, docked lambs as well as lambs on high level of energy diet showed better weight gain (P < 0.05). No significant difference (P > 0.05) was observed for WCW and fat depth at the 12th rib between docked and control lambs, but WCW was significantly affected by the diet energy density (P < 0.05). Docked lambs produced leaner carcasses than did the intact lambs (P < 0.01). Docking did not influence feed consumption, but improved meat quality and amounts (by weight and percentage) of high price carcass cuts, and reduced total fat content as a percentage of the live weight. Dietary energy level affected the average daily gain and daily feed intake (P < 0.05). The most abundant FA in caudal and omental fat depots was oleic acid. Significant difference was observed in the percentage of all fatty acids between omental and caudal fat depots (P < 0.05). A negative correlation (-0.8465) was recorded between oleic and stearic acid concentrations (P < 0.001). In conclusion, docking of Kurdi lambs improved most feedlot characteristics (such as daily gain and feed efficiency) and may be recommended under industrial sheep production.
https://lst.uk.ac.ir/article_477_4debe0767ad9df2cfe84b0d2afb44693.pdf
2012-11-28
19
27
10.22103/jlst.2012.477
Kurdi sheep
docking
carcass characteristics
fatty acid composition
A.
Moharrery
alimoh@mailcity.com
1
Animal Science Department, Agricultural College, Shahrekord University, P.O. Box 115, Shahrekord, Iran
LEAD_AUTHOR
M.
Khorvash
2
Animal Science Department, Agricultural College, Isfahan University of Technology, 84156 Isfahan, Iran
AUTHOR
H.
Khadivi
3
Livestock Affair, Jehad-e-Keshavarzi Organization, Khorasan Province, Iran
AUTHOR
ORIGINAL_ARTICLE
Concentration of serum total iodine and thyroid hormones in Holstein cows in central Iran
The aim of this study was to evaluate total iodine, triiodothyronine (T3) and thyroxine (T4) status in the blood serum of Holstein cows on six farms in central Iran. Total iodine, T3 and T4 concentrations were measured in 90 blood serum samples (15 per farm). Mean concentrations of total iodine (38.80 ± 1.52 µg/l) and T3 (1.57 ± 0.10 nmol/l) were lower but the mean concentration of T4 (45.60 ± 1.53 nmol/l) was greater than the critical levels (P < 0.01). Deficiency of total iodine, T3 and T4 was diagnosed in 82%, 85% and 35% of the cows, respectively. It was concluded that cows in central Iran were deficient in total serum iodine concentration. Increasing dietary iodine and further studies on the interaction between iodine and other minerals is recommended.
https://lst.uk.ac.ir/article_478_05415ec6a8eee64c815526e99636812b.pdf
2013-04-28
26
28
10.22103/jlst.2013.478
iodine
triiodothyronine
thyroxine
blood
Holstein cows
central Iran
S.
Tadayonfar
1
Department of Animal Science and Veterinary Research, Isfahan Research Center for Agriculture and Natural Resources, Isfahan, Iran
AUTHOR
V.
Noaman
vnoaman@gmail.com
2
Department of Animal Science and Veterinary Research, Isfahan Research Center for Agriculture and Natural Resources, Isfahan, Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
Association of TG-repeats in the 5’-flanking region of bovine growth hormone receptor (GHR) gene with milk production traits and somatic cell count in Holstein cattle
The growth hormone receptor (GHR) is a member of cytokine/hematopoietin family that mediates the biological actions of growth hormone (GH) on target tissues. Therefore, the purpose of this study was to examine the association of TG-repeat polymorphisms in the 5’-flanking region of bovine GHR gene with milk production traits and somatic cell score (SCS) in Holstein cattle of Iran. The part of 5’-flanking region of GHR gene that encompassed TG-repeat was screened by single strand conformation polymorphism (SSCP) method and DNA sequencing. Five hundred eighteen Iranian Holstein cows were genotyped, giving 3 distinct SSCP patterns (A, B, and C). Frequencies of these patterns for the amplified fragment were 0.21, 0.26 and 0.53, respectively. Statistical analysis revealed that TG-repeat had a significant effect on average daily milk production (P < 0.05) and tended to associate with fat and protein percentage. No significant difference was observed between TG-genotypes and SCS. The association identified in the TG-repeat of GHR gene may have potential to serve as candidate genetic marker for marker assisted selection (MAS) in cattle.
https://lst.uk.ac.ir/article_481_984d662f492d67af53a392be16937c6e.pdf
2013-04-28
29
34
10.22103/jlst.2013.481
GHR gene
5’-flanking region
SSCP
microsatellite
Cattle
M.
Muhaghegh-Dolatabady
mmuhaghegh@yu.ac.ir
1
Department of Animal Science, Faculty of Agriculture, Yasouj University, Yasouj, Iran
LEAD_AUTHOR
J.
Habibizad
2
Department of Animal Science, Faculty of Agriculture, Yasouj University, Yasouj, Iran
AUTHOR
M. R.
Bahreini Behzadi
3
Department of Animal Science, Faculty of Agriculture, Yasouj University, Yasouj, Iran
AUTHOR
ORIGINAL_ARTICLE
Estimation of (co) variance components and genetic parameters for growth traits in Arman sheep
(Co) variance components and genetic parameters for growth traits in Arman sheep were estimated, using data collected during an 11-year period (1999-2010), by applying the restricted maximum likelihood (REML) procedure under univariate and bivariate animal models. The studied traits were body weight of lamb at birth (BW), body weight at 3 months of age as weaning weight (WW), body weight at 6 months (6MW), body weight at 9 months (9MW), yearling weight (YW), average daily gain from birth to weaning (ADG) and the Kleiber ratio (KR) from birth to weaning. Significant random effects for each trait were determined by AIC test fitting the additive direct genetic effect, additive maternal effect, covariance between additive direct and additive maternal effect, maternal permanent environmental and maternal temporary environmental (common litter) effects under nine animal models. Univariate analyses were carried out under the most appropriate model, determined by AIC test. Direct heritability estimates for BW, WW, ADG, KR, 6MW, 9MW and YW were 0.03 ± 0.02, 0.15 ± 0.02, 0.16 ± 0.02, 0.04 ± 0.03, 0.15 ± 0.04, 0.08 ± 0.04 and 0.16 ± 0.02, respectively. Maternal additive genetic effect was fitted only for BW, WW and ADG; corresponding estimates of 0.20 ± 0.02, 0.13 ± 0.01 and 0.07 ± 0.03 were obtained for maternal heritability of BW, WW and ADG, respectively. Maternal permanent environmental effects had a small contribution in expression of pre-weaning growth traits and 6MW, and led to estimates of 0.05 ± 0.02, 0.06 ± 0.04, 0.12 ± 0.03, 0.07 ± 0.02 and 0.06 ± 0.03 for maternal permanent environmental variance as a proportion of phenotypic variance (c2) of BW, WW, ADG, KR and 6MW, respectively. The magnitude of ratio of common litter variance to phenotypic variance (l2) was 0.07 ± 0.02 and 0.09 ± 0.02 for BW and WW, respectively. Direct genetic correlations were positive and ranged from 0.08 for KR-YW to 0.83 for WW-ADG; the phenotypic ones ranged from 0.19 for KR-9MW to 0.96 for WW-ADG. The results showed that the inclusion of maternal effects in genetic evaluation of early growth traits in Arman sheep is of crucial importance.
https://lst.uk.ac.ir/article_479_1b46d1ae82b0af721a2d1c2b6d200ed3.pdf
2013-04-28
35
43
10.22103/jlst.2013.479
maternal effects
Body weights
animal model
(co) variance components
M.S.
Mokhtari
msmokhtari@ut.ac.ir
1
Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, P. O. Box 31587-77871, Karadj, Iran
LEAD_AUTHOR
M.
Moradi Shahrebabak
2
Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, P. O. Box 31587-77871, Karadj, Iran
AUTHOR
H.
Moradi Shahrebabk
3
Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, P. O. Box 31587-77871, Karadj, Iran
AUTHOR
M.
Sadeghi
4
Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, P. O. Box 31587-77871, Karadj, Iran
AUTHOR
Abbasi, M.A., Abdollahi-Arpanahi, R., Maghsudi, A., Vaez Torshizi, R., Nejati-Javaremi, A., 2012. Evaluation of models for estimation of genetic parameters and maternal effects for early growth traits of Iranian Baluchi sheep. Small Ruminant Research 104, 62-69.
1
Abegaz, S., van Wyk, J.B., Olivier, J.J., 2005. Model comparisons and genetic and environmental parameter estimates of growth and the Kleiber ratio in Horro sheep. South African Journal of Animal Science. 35, 30–40.
2
Akaike, H., 1974. A new look at the statistical model identification. IEEE, Trans. Automatic Control. 19, 716-723.
3
Al-Shorepy, S.A., 2001. Estimates of genetic parameters for direct and maternal effects on birth weight of local sheep in United Arab Emirates. Small Ruminant Research 39, 219-224.
4
Duguma, G., Schoeman, S.J., Cloete, S.W.P., Jordan, G.F., 2002. Genetic parameter estimates of early growth traits in the Tygerhoek Merino flock. South African Journal of Animal Science 32, 66–75
5
Eskandarinasab, M., Ghafouri-Kesbi, F., Abbasi, M.A., 2010. Different models for evaluation of growth traits and Kleiber ration in an experimental flock of Iranian fat-tailed Afshari sheep. Journal of Animal Breeding and Genetics 127, 26-33.
6
Ghafouri-Kesbi, F., Abbasi, M.A., Afraz, F., Babaei, M., Baneh, H., Abdollahi-Arpanahi, R., 2011. Genetic analysis of growth rate and Kleiber ratio in Zandi sheep. Tropical Animal Health and Production 43, 1153–1159
7
Gowane, G.R., Ashish Chopra., Ved Prakash., Arora, A.L., 2010. Estimates of (co)variance components and genetic parameters for body weights and first greasy fleece weight in Malpura sheep. Livestock Science 131, 94–101.
8
Jafaroghli, M., Rashidi, A., Mokhtari, M.S., Shadparvar, A.A., 2010. (Co)Variance components and genetic parameter estimates for growth traits in Moghani sheep. Small Ruminant Research 91, 170-177.
9
Freking, B. A., Leymaster, K. A. 2004. Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale Breeds of Sheep. IV. Survival, Growth, and Carcass Traits of F1 Lambs. Journal of Animal Science 82, 3144-3153.
10
Kosgey, I.S. Okeyo, A.M., 2007. Genetic improvement of small ruminants in low-input, smallholder production systems: Technical and infrastructural issues. Small Ruminant Research 70, 76-88.
11
Maniatis, N., Pollott, G.E., 2003. The impact of data structure on genetic (co)variance components of early growth in sheep, estimated using an animal model with maternal effects. Journal of Animal Science 81, 101-108.
12
Maria, G.A., Boldman, K.G., Van Vleck, L.D., 1993. Estimates variances due to direct and maternal effects for growth traits of Romanov sheep. Journal of Animal Science 71, 845–849.
13
Matika, O., van WyFk, J.B., Erasmus, G.J., Baker, R.L. 2003. Genetic parameter estimates in Sabi sheep. Livestock Production Science 79, 17–28.
14
Meyer, K., 2007. WOMBAT: a tool for mixed model analyses in quantitative genetics by Restricted Maximum Likelihood (REML). Journal of Zhejiang University Science B 11, 815–821.
15
Miraei-Ashtiani, S.R., Seyedalian, S.A.R., Moradi Shahrbabak, M., 2007. Variance components and heritabilities for body weight traits in Sangsari sheep, using univariate and multivariate animal models. Small Ruminant Research 73, 109–114.
16
Mohammadi, Y., Rashidi, A., Mokhtari, M.S., Esmailizadeh, A.K., 2010. Quantitative genetic analysis of growth traits and Kleiber ratios in Sanjabi sheep. Small Ruminant Research 93, 88-93.
17
Mohammadi, K., Rashidi, A., Mokhtari, M.S., Beigi Nassiri, M.T., 2011. The estimation of (co)variance components for growth traits and Kleiber ratios in Zandi sheep. Small Ruminant Research 99, 116-121.
18
Mokhtari, M.S., Rashidi, A., Mohammadi, Y., 2008. Estimation of genetic parameters for post-weaning traits of Kermani sheep. Small Ruminant Research 80, 22-27.
19
Ozcan, M., Ekiz, B., Yilmaz, A., Ceyhan, A., 2005. Genetic parameter estimates for lamb growth traits and greasy fleece weight at first shearing in Turkish Merino sheep. Small Ruminant Research 56, 215–222.
20
Rashidi, A., Mokhtari, M.S., Safi Jahanshahi, A., Mohammad Abadi, M.R., 2008. Genetic parameter estimates of pre-weaning growth traits in Kermani sheep. Small Ruminant Research 74, 165-171.
21
Riggio, V., Finocchiaro, R., Bishop, S.C., 2008. Genetic parameters for early lamb survival and growth in Scottish Blackface sheep. Journal of Animal Science 86, 1758-1764.
22
Safari, E., Fogarty, N.M., Gilmour, A.R., 2005. A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep. Livestock Production Science 92, 271-289.
23
SAS Institute, 2002. SAS User’s Guide, Version 9.1, Statistics. Cary, NC: SAS Institute Inc.
24
Scholtz, M.M., Roux, C.Z., 1988. The Kleiber ratio (growth rate/metabolic mass) as possible selection criteria in the selection of beef cattle. In: Proceedings of the 3rd World Congress on Sheep and Beef Cattle Breeding, Vol. 2, Paris, France, pp. 373–375.
25
Shrestha, J.N.B., 2005. Conserving domestic animal diversity among composite populations. Small Ruminant Research 56, 3-20.
26
Snyman, M.A., Erasmus, G.J., van Wyk, J.B., Olivier, J.J., 1995. Direct and maternal (co)variance components and heritability estimates for body weight at different ages and fleece traits in Afrino sheep. Livestock Production Science 44, 229–235.
27
Vatankhah, M., Talebi, M.A., 2008. Heritability estimates and correlations between production and reproductive traits in Lori-Bakhtiari sheep. South African Journal of Animal Science 38 (2), 110-118.
28
Yazdi, M.H., Engstrom, G., Nasholm, A., Johansson, K., Jorjani, H., Liljedahl, L.E., 1997. Genetic parameters for lamb weight at different ages and wool production in Baluchi sheep. Animal Science 65, 247–255.
29
Yilmaz, O., Denk, H., Bayram, D., 2007. Effects of lambing season, sex and birth type on growth performance in Norduz lambs. Small Ruminant Research 68, 336-339.
30
Zamani, P., Mohammadi, H., 2008. Comparison of different models for estimation of genetic parameters of early growth traits in the Mehraban sheep. Journal of Animal Breeding and Genetics 125, 29-34.
31
ORIGINAL_ARTICLE
Genetic analysis of ewe body weight in Lori-Bakhtiari sheep using random regression models
(Co)variance components and genetic parameters for test day ewe body weight of Lori-Bakhtiari sheep were estimated using a random regression model (RRM). The data consisted of 22153 individual body weight records, obtained from 1994 ewes (progeny of 205 sires and 1010 dams) between 371 and 3416 days of age, collected from the flock stud of Lori-Bakhtiari Sheep Breeding Station in Shahrekord, Iran during 1989 to 2008, with a total of 2225 animals in the pedigree. The model included the fixed effects (year of production, litter size and stage of production cycle) and random additive genetic, permanent environmental and residual effects. Random regression models were fitted with order 1 to 5 (k = 2 to 6) for additive genetic and permanent environmental effects. The residual variance in each model was assumed to be homogeneous or heterogeneous with 9 age classes. Results indicated that the 5th order (k = 6) with heterogeneous residual variance was more appropriate than others. Based on selected RRM, the additive genetic variance, permanent environmental variance and phenotypic variance increased with the ewe age. The heritability estimates were 0.38 ± 0.04, 0.44 ± 0.04, 0.42 ± 0.04, 0.38 ± 0.04, 0.37 ± 0.05, 0.42 ± 0.06, 0.48 ± 0.10 and 0.50 ± 0.14 for the ewe body weights at 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, 7.5 and 8 years of age, respectively. The proportion of permanent environmental variance to phenotypic variance ranged from 0.16 ± 0.04 to 0.39 ± 0.05. Genetic and phenotypic correlations of ewe body weight between consecutive test days were high, but decreased when the interval between body weight measurements increased, ranging from 0.45 ± 0.08 to 0.99 ± 0.09 and 0.37 ± 0.05 to 0.73 ± 0.01, respectively. Thus, due to moderate genetic correlations between ewe body weight at early and older ages, genetic analysis using RRM may be recommended for improvent of ewe body weight in Lori-Bakhtiari sheep.
https://lst.uk.ac.ir/article_480_84aabc52225d2d12abecab1ecf031c62.pdf
2013-04-28
44
49
10.22103/jlst.2013.480
heritability
genetic correlation
random regression model
Lori-Bakhtiari sheep
M.
Vatankhah
vatankhah_mah@yahoo.com
1
Department of Animal Science, Agriculture and Natural Resources Research Center, Shahrekord, Iran
LEAD_AUTHOR
Albuquerque, L.G., Meyer, K. 2001. Estimation of covariance functions for growth from birth to 630 days of age in Nelore cattle. Journal of Animal Science 79, 275-277.
1
Bedier, N.Z., Younis, A., Galal, E.S.E., Mokhtar, M. 1992. Optimum ewe in desert Barki sheep. Small Ruminant Research 7, 1-7.
2
Fischer, T.M., Van Der Werf, J.H.J., Banks, R.G., Ball, A.J. 2004. Description of lamb growth using random regression on field data. Livestock Production Science 89, 175-185.
3
Fogarty, N.M. 1995. Genetic parameters for live weight, fat and muscle measurements, wool production and reproduction in sheep: a review. Animal Breeding Abstracts 63, 101-143.
4
Gallivan, C. 1996. Breeding objectives and selection indexes for genetic improvement of Canadian sheep. Ph.D. Thesis. University of Guelph, Canada.
5
Kirkpatrick, M., Lofsvold, D., Bulmer, M. 1990. Analysis of the inheritance and evolution of growth trajectories. Genetics 124, 979-993.
6
Lewis, R.M., Brotherstone, S. 2002. A genetic evaluation of growth in sheep using random regression techniques. Animal Science 74, 60-70.
7
Meyer, K. 1998. Estimating covariance functions for longitudinal data using random regression model. Genetic Selection Evolution 30, 221-240.
8
Meyer, K. 2002. Estimation of covariance functions for growth of Australian beef cattle from large set of field data.Proceeding of the 7th World Congress on Genetics Applied to Livestock Production. August 19-23, Montpellier, France.
9
Meyer, K. 2006. WOMBAT- A program for mixed model analyses by restricted maximum likelihood. User notes, Animal Genetics and Breeding Unit, Armidale, Australia.
10
Nasholm, A., Danell, O. 1996. Genetic relationships of lamb weight, maternal ability and mature ewe weight in Swedish fine wool sheep. Journal of Animal Science 74, 329-339.
11
Nephawe, K.A. 2004. Application of random regression models to the genetic evaluation of cow weight in Bonsmara cattle of South Africa. South African Journal of Animal Science 34, 166-173.
12
Safari, E., Fogarty, N.M., Gilmour, A.R. 2005. A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep. Livestock Production Science 92, 271-289.
13
SAS. 2000. Release 6. 12, SAS Institute Inc., Cary, North Carolina, USA.
14
Vatankhah, M. 2005. Defining a proper breeding scheme for Lori-Bakhtiari sheep in village system. Ph.D. Thesis. University of Tehran, Iran.
15
Vatankhah, M., Talebi, M.A. 2009. Genetic and non-genetic factors affecting mortality in Lori-Bakhtiari lambs. Asian-Australasian Journal of Animal Science 22, 459-464.
16
Vatankhah, M., Salehi, S.A. 2010. Genetic and non-genetic factors affecting Lori-Bakhtiari ewe body weight and its relationship with productivity. Small Ruminant Research 94, 98-102.
17
ORIGINAL_ARTICLE
Genetic parameter estimates of body weight traits in Iran-Black sheep
The objective of the current study was to estimate the genetic parameters for body weight traits at different ages in Iran-Black sheep. Data collected during a 24-year period (1984-2008) on body weight were used to model the growth trajectory and estimate genetic parameters. Studied traits were birth weight (BW), weaning weight at 3 months of age (WW), 6 months weight (6MW), 9 months weight (9MW) and yearling weight (YW). Genetic parameters were estimated using the restricted maximum likelihood (REML) procedure under univariate and multivariate animal models. Random effects were explored by fitting additive direct genetic effects, maternal additive genetic effects, maternal permanent environmental effects, the covariance between direct and maternal genetic effects and common litter effects in twelve different models for analysis of each trait. Direct heritabilities estimated for BW, WW, 6MW, 9MW and YW were 0.02, 0.14, 0.16, 0.25 and 0.34, respectively. Maternal additive genetic variance had significant effects on the expression of body weights from birth to six months of age; resulting in values of 0.24, 0.02 and 0.09 for maternal heritability of BW, WW and 6MW, respectively. Maternal permanent environmental effects were only significant for BW, WW and 9MW leading to estimates of 0.09, 0.13 and 0.08 for maternal permanent environmental variance as a proportion of phenotypic variance (c2) for these traits, respectively. The magnitude of the ratio of common litter variance to phenotypic variance (l2) was 0.24 and 0.13 for BW and 6MW, respectively. The present study showed the importance of inclusion of maternal effects in designing appropriate breeding programs for genetic improvement in Iran-Black lambs for body weight.
https://lst.uk.ac.ir/article_482_62764fdaf4a79ee75fabe381f49282b0.pdf
2013-04-28
50
56
10.22103/jlst.2013.482
heritability
genetic correlation
Growth traits
sheep
A.
Rashidi
arashidi@uok.ac.ir
1
Department of Animal Science, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
Divergent selection for four-week body weight in Japanese quail (Coturnix coturnix japonica): response to selection and realized heritability
The Japanese quail has been utilized as a research species in establishing the genetic relationships that may also be present in other species. Divergent phenotypic selection for 4-wk BW was conducted for three generations in high (HW) and low (LW) lines. Within each line, 50 females and 25 males were selected among 600 birds, based on 4-wk BW. Mean BW at 4 wk of age in the base generation was 186.2 and 178.6 g for females and males, respectively. In the 3rd generation, the mean of 4-wk BW for male and female birds was 214.5 and 208.1 in HW line and 173.5 and 167.8 in LW lines, respectively. The realized heritability was estimated as 33.4% and 28.3% for females and males in HW lines and 20.3% and 20.2% for females and males in LW lines. The results suggested the effectiveness of phenotypic selection for body weight in Japanese quails, although the hatchability decreased in the heavier birds.
https://lst.uk.ac.ir/article_487_a2d920ed45040ac2d5a918c7ccde02d3.pdf
2013-04-28
57
59
10.22103/jlst.2013.487
divergent selection
realized heritability
Japanese quail
A.
Ayatollahi Mehrgardi
a_ayatmehr@yahoo.com
1
Department of Animal Science, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran
LEAD_AUTHOR