The growth and survival characteristics of lambs produced by commercial crossbreeding Kıvırcık ewes with F2 rams with the German Black-Headed Mutton genotype (original) (raw)
Ankara Üniversitesi Veteriner Fakültesi Dergisi, 2015
In this study, the data were collected from 1271 heads of Awassi lambs raised in the GAP International Agricultural Research and Training Center in Diyarbakır, Turkey. Birth and weaning weight (at 90 days) of lambs were measured and average daily weight gain from birth to weaning was calculated. The effect of the years and season of lambing, age of dam, sex and birth type on birth weight (BWT), weaning weight (WWT) and average daily weight gain (ADWG) from birth to weaning were investigated. Overall means were 4.81±0.022 kg for BWT, 22.99±0.196 kg for WWT and 201.67±1.173 g for ADWG. The all tarits in the analyses were significantly (P<0.05) affected by all factors in the model. In addition, lambs born heavier grew faster and reached heavier WWT (p<0.01). Based on the single and multiple trait analyses, heritability estimates ranged from 0.21 to 0.25 for BWT, from 0.13 to 0.17 for WWT and from 0.13 to 0.17 for ADWG. Estimates of genetic correlations between BWT with WWT and ADWG were 0.61 and 0.61, respectively.
Kafkas Universitesi Veteriner Fakultesi Dergisi, 2012
In this study, canonical correlation analysis was applied to estimate the relationship between six different morphologic traits (X set-birth weight (BW), body length (BL), height at withers (HW), chest depth (CD), chest width (CW) and chest girth (CG)) measured at birth and the morphological traits measured at weaning time (Y set-weaning weight (WW), body length (BL_W), height at withers (HW_W), chest depth (CD_W), chest width (CW_W) and chest girth (CG_W)) measured from 121 Karayaka lambs, raised at Gaziosmanpasa University. First of estimated six different canonical correlation coefficients (CCC) (r=0.668) between the pairs of canonical variables were found significant (P<0.05). The results of canonical correlation analysis indicated that height at withers, chest girth and birth weight had largest contribution for the explanatory capacity of canonical variables estimated from the morphologic traits of Karayaka lambs at the birth when compared with other body measurements. Height withers and chest girth had largest contribution for the explanatory capacity of canonical variables estimated from the morphological traits of the lambs at the weaning time when compared with other body measurements. As results of this study showed that height at withers, body weight and chest girth measured at birth can be used as early selection criteria for genetic improvement in Karayaka lambs.
Czech J. Anim. Sci, 2002
e objective of this study was to evaluate the effect of crossing on body weight and growth ability of lambs from birth to weaning, including the effect of litter size, sex, dam age, dam weight at mating, dam weight after lambing and year of rearing. e study was conducted on the Awassi sheep flock and their crossbreds with Charollais and Romanov breeds maintained at the Agriculture Centre for Research and Production at Jordan University of Science and Technology, Irbid. In 1999 and 2000 the live weight was determined in 192 lambs (70 Awassi, 63 Awassi × Charollais F 1 crossbred and 59 Awassi × Romanov F 1 crossbred) at birth and subsequently every fortnight until weaning by weighing on digital scales to the nearest 0.1 kg. Average live weight of lambs at birth was 4.20 ± 1.15 kg and at the age of 15, 30, 45 and 60 days 8.72 ± 2.12 kg, 12.12 ± 2.77 kg, 15.50 ± 3.70 kg and 19.27 ± 4.59 kg, respectively. ADG of lambs from birth until weaning was 248 ± 0.07 g. Genotype of lambs and litter size affected ADG, live weight of lambs at birth, 15, 30, 45 and 60 days significantly (P ≤ 0.05-0.001). Investigations of the effect of sex on live weight of lambs at birth and at 60 days showed that the differences between males and females were statistically significant (P ≤ 0.05-0.01). Differences in ADG and live weight at 15, 30 and 45 days according to dam age were significant (P ≤ 0.05-0.01). e effect of dam weight at mating on live weight of lambs at birth, ADG until weaning and live weight at weaning was not confirmed. e effect of dam weight at lambing on ADG, live weight of lambs at birth, at 45 days of age and until weaning was not confirmed. Regressions of BW, ADG and weight at 15, 30, 45 and 60 days age of lambs on dam weight after lambing were significant (P ≤ 0.001). Likewise, live weight of lambs at birth, ADG until weaning and live weight at 15, 30 a 45 days of age were affected by the seasons of lambing (P ≤ 0.01-0.001).
South African Journal of Animal …, 1993
Twenty-four sets of full-sib ram lambs, each born from a different sire, were kept individually in pens and hand-reared from birth up to 50 kg live mass. Feed intake and mass of each lamb were determined every third day. Growth curves [ ln(mass) against ln(cumulative feed intake)] were plotted for each lamb. Three growth phases could be identified. Very low heritabilities (/22 ) were calculated for feed conversion ratio in the second and third phases whereas the hz in Phase I was 0.32 'r 0.40. Heritability of average daily gain (ADG), estimated with least squares means and regression methods, was 0.40 and 0.39 in Phase I, 0.68 and 0.48 in Phase II, and A.26 and 0.18 in Phase Itr. Heritability of the Kleiber ratio followed the sarne trend but was generally higher. Only the product-moment correlations between feed conversion, ADG and the Kleiber ratio within the same growth phase, differed significantly from zero (P < 0.01). Genetic and phenotypic correlations between traits over phases, were low and insignificant. Vier-en-twintig stelle volsib-ramlammers, elk van 'n verskillende vader, is kunsmatig vanaf geboorte tot 50 kg lewende massa in individuele kratte grootgemaak. Individuele voerinnames en massas is elke derde dag bepaal. Groeikurwes I ln(massa) teen ln(kumulatiewe voerinname)] is vir elke lam bepaal. Drie relatief duidelike groeifases is waargeneem. Lae oorerflikhede @\ is vir voeromset in die tweede en derde fases bereken terwyl hz in die eerste fase 0.32 -t-0.40 was. Oorerflikheid van gemiddelde daaglikse toename (GDT), bepaal met die kleinste kwadrate en regressiemetodes, was onderskeidelik 0.40 en 0.39 in Fase I, 0.68 en 0.48 in Fase If, en 0.26 en 0.18, respektiewelik in Fase III. Oorerflikheid van die Kleiberverhouding het dieselfde patroon gevolg maar wils in die algemeen ho€r. Slegs die produkmomentkorrelasies tussen voeromset, GDT en die Kleiberverhouding binne dieselfde groeifase, het betekenisvol (P < 0.01) van nul afgewyk. Genetiese en fenotipiese korrelasies tussen kenmerke oor fases, was laag en onbeduidend.
İ: Effects of different fattening systems on fattening performance, slaughter and carcass characteristics of male Tuj lambs. Abstract The purpose of this study were to determine effects of fattening systems on fattening performance (n=39) and slaughter and carcass characteristics (n=24) in male Tuj lambs. Three different fattening groups were formed as extensive (n=13), semi-intensive (n=13) and intensive (n=13). Lambs in the extensive group were grazed in pasture. In addition to pasture, concentrated feed was given to lambs in the semi-intensive group. High quality fodder and concentrated feed were given to those in the intensive group. The study was completed in 90 d. Final live weights of extensive, semi-intensive and intensive groups were 31.19, 41.22, and 40.56 kg (P<0.001), respectively, and for daily live weight gain were (DLWG) 117.52, 229.66, and 221.11 g (P<0.001), respectively. Feed conversion rates (FCR) were 3.05 and 5.16 respectively in the semi-intensive and intensive fattening. It was found that hot carcass weight was 13.41, 19.51, and 19.89 kg (P<0.001) in extensive, semi-intensive, and intensive fattening groups respectively. Hot carcass yield was 43.11, 46.95, and 49.77% (P<0.001) in extensive, semi-intensive, and intensive fattening groups respectively. Consequently; leg, foreleg, shoulder, neck, flank, and kidney percentages, and spleen and full stomach weights of lambs in the extensive group were higher than in semi-extensive and entensive groups. Although there was no statistical difference between semi-extensive and entensive groups in respect to fattening performance, slaugher weight, hot and cold carcass weights, entensive group was higher than the other groups in respect to hot and cold carcass yield. Özet Bu araştırma, erkek Tuj kuzularında besi sistemlerinin besi performansı (n=39), kesim ve karkas özelliklerine (n=24) etkisini belirlemek amacıyla yapılmıştır. Araştırmada ekstansif (n=13), yarı entansif (n=13) ve entansif (n=13) olmak üzere 3 değişik besi gruba oluşturulmuştur. Ekstansif grup merada otlatılmıştır. Yarı entansif gruba meraya ilaveten konsantre yem verilmiştir. Entansif gruba ise kaliteli kuru ot ve konsantre yem verilmiştir. Araştırma 90 günde tamamlanmıştır. Ekstansif, yarı entansif ve entansif besi gruplarında besi sonu ağırlığı sırasıyla 31.19, 41.22 ve 40.56 kg (P<0.001), günlük canlı ağırlık artışı sırasıyla 117.52, 229.66 ve 221.11 g (P<0.001) olarak belirlenmiştir. Yarı entansif ve entansif beside yemden yararlanma oranı sırasıyla 3.05 ve 5.16 olarak tespit edilmiştir. Ekstansif, yarı entansif ve entansif beside sıcak karkas ağırlığı 13.41, 19.51 ve 19.89 kg (P<0.001) olarak belirlenmiştir. Sıcak karkas randımanı aynı sıra ile %43.11, 46.95 ve 49.77 (P<0.001) olarak tespit edilmiştir. Sonuç olarak; ekstansif besi grubundaki kuzuların but, kol, omuz, boyun, etek ve böbrek oranları ile dalak ve dolu mide ağırlığı, yarı entansif ve entansif besi gruplarından yüksek bulunmuştur. Yarı entansif ve entansif gruplar arasında besi performansı, kesim ağırlığı, sıcak ve soğuk karkas ağırlıkları bakımından istatistiki bir fark bulunmamasına rağmen, sıcak ve soğuk karkas randımanı bakımından entansif grup, diğer gruplardan yüksek belirlenmiştir.
2002
e goal of the study was to examine and evaluate the effect of lamb genotype on the growth, feed consumption, feed conversion and carcass value of Awassi ram lambs, F 1 crossbreds of Romanov × Awassi and Charollais × Awassi. Average daily weight gain and total weight gain during the trial were 199 ± 0.01 g and 12.33 ± 0.58 kg in pure Awassi ram lambs, 216 ± 0.01 g and 13.37 ± 0.71 kg in F 1 crossbreds A × Ch and 268 ± 0.01 g and 16.66 ± 0.58 kg in F 1 crossbreds A × R (P ≤ 0.01). Statistically significant differences between the genotypes were found in diagonal body length, rump height and chest girth (P ≤ 0.01). Evaluation of carcass by-products shows that the genotype affected the weight of full and empty digestive tracts, small intestine, heart, liver, intestinal fat, testicles, kidney and kidney fat (P ≤ 0.05 -0.01). e highest dressing percentage (including fat tail) in warm condition was 50.93 ± 1.11% in Awassi ram lambs and if compared with F 1 crossbred A × Ch 50.34 ± 1.36% and F 1 crossbreeds A × R 49.05 ± 1.11% no statistically significant difference was found. e highest percentage ratios of leg, loin and rack, which represent the prime meat of carcass, 57.08 ± 1.72% were in F 1 crossbreds A × Ch, 54.14 ± 1.40% in F 1 crossbreds A × R and 48.99 ± 1.40% in Awassi ram lambs (P ≤ 0.001). e highest fat tail percentage 13.4 ± 1.06% was in Awassi ram lambs and the lowest 1.76 ± 1.06% in F 1 crossbreds A × R (P ≤ 0.001). In general, the results of this study demonstrated that F 1 crossbreeds A × R and F 1 crossbreds A × Ch were superior to Awassi ram lambs in daily weight gain and total weight gain, feed conversion, lower costs per 1 kg meat gain and mainly in the carcass indicators.
Turkish Journal of Veterinary and Animal Sciences
The purpose of this study was to compare the fattening performance, slaughter and carcass characteristics of lambs which were produced by crossbreeding with Kivircik sheep, the local breed in the Marmara region with German Black-Headed Mutton (GBM), the mutton breed which import from Germany. Forty lambs, the live weights of which were around 25.0 kg, were divided into 4 groups according to genotype and sex at the beginning of the fattening period. The average daily live gains were found 279, 210, 283 and 201 day/g, and fed conversion efficiencies were 5.018, 6.286, 4.854 and 6.197 kg, respectively in genotype groups of the Bandirma-I male, female, the Bandirma-II male and female lambs. The crossbred male lambs gained weight faster and consumed less feed per unit weight gain during the fattening program than the female lambs. Whereas, there were no fattening and carcass traits differences between crossbreds Bandirma-I and Bandirma-II genotype lambs.
South African Journal Of Animal Science
In this study the possibilities of using the Ile de France x Akkaraman (G1) genotype (IDFAG1) in improving the growth performance and carcass characteristics of fat-tailed Karakas sheep raised in rural farm conditions in the Van Region of Eastern Anatolia, Turkey, were investigated. The aim was to obtain some preliminary results for future studies which will be designed to develop a genotype which has the ability to adapt to the region’s conditions, has a high yield and quality meat, grows fast, has a high feed conversion ability and a thin fat tail. Growth and feedlot performances and carcass characteristics of Karakas (KAR) and crossbred (IDFAK) lambs obtained from the mating of IDFAG1 rams with Karakas ewes were evaluated. A total of 97 KAR and IDFAK lambs reared under farm conditions was evaluated for growth characteristics. For the evaluation of feedlot performance and carcass characteristics, 10 KAR and seven IDFAK single-born male lambs weaned at two months of age were subjec...
The aim of study was to investigate the carcass quality of Turkish Merino, Ramlic, Kivircik, Chios and Imroz breeds in north-western Turkey under an intensive production system. After weaning at approximately 85 days of age, 46 lambs from Turkish Merino, Ramlic, Kivircik, Chios and Imroz breeds were fattened for 56 days. slaughter weights were 47. 39, 45.68, 47.27, 31.08 and 29.82 kg and chilled carcass weights were 23. 35, 22.33, 23.51, 14.33 and 13.75 kg, respectively (P<0.001). Improved Turkish Merino and Ramlic and indigenous Kivircik lambs had higher carcass measurements than indigenous Chios and Imroz lambs. Chios lamb carcasses had the highest tail root fat yellowness and tail percentage while having the lowest fatness score, omental and mesenteric fat percentage and kidney knob and channel fat percentage. Turkish Merino lambs had higher shoulder percentage, lean percentage and lean/total fat ratio in the hind leg and produced less total fat in the hind leg than Ramlic and Kivircik lambs. These results indicate that improved Turkish Merino might be used to produce high quality lamb carcasses in north-western Turkey. Among indigenous breeds Kivircik showed an outstanding carcass production performance. Lo scopo di questo studio è stato quello di rilevare le caratteristiche qualitative delle carcasse in razze Turkish Merino, Ramlic, Kivircik, Chios e Imroz allevate con sistema intensivo nel territorio del nord-ovest della Turchia. Dopo lo svezzamento a circa 85 giorni di età, 46 agnelli di razza Turkish Merino, Ramlic, Kivircik, Chios e Imroz sono stati ingrassati per 56 giorni. Il peso alla macellazione è stato di 47,39 -45,68 -47,27 -31,08 e 29,82 kg, e quello delle carcasse refrigerate di 23, 35 -22,33 -23,51 -14,33 e 13,75 Ital.664
Biotechnology in Animal Husbandry, 2016
The objective of this study was to determine the effects of the father's breed onto the carcass characteristics in lambs from the Bulgarian Dairy Synthetic Population and its F 1 crosses with Ile de France and Mutton Charolais breeds. The scientific study took place at the Sheep Farm with the Agricultural Institute of Stara Zagora, Bulgaria. Object of the study were lambs from the Bulgarian Dairy Synthetic Population and its crosses with Ile de France and Mutton Charolais breeds. After reaching a live weight of 21-24 kg, 9 male lambs of different crosses were slaughtered. Slaughter took place at a licensed slaughter house. The lamb carcasses were chilled for 24 hours. Following this, linear measurements were made on the left carcass halves.The father's breed has a significant proven effect onto the large and small circumference of the leg (P≤ 0.001) and a proven effect onto the carcass length (P≤ 0.01). The Ile de France crosses feature 17.44% bigger leg circumference in comparison with the animals from the reference group. Similar is the situation with the Mutton Charolais crosses where we have 14.93% bigger leg circumference compared to that in the reference group. Determined is also an effect onto the weight of the chilled carcass and the carcass yield. The lambs from the trial groups have a proven bigger leg weight (P≤ 0.001), proven bigger chilled carcass weight (P≤ 0.01) and they show a trend for proving the effect on the carcass yield (P≤ 0.05).
Alınteri zirai bilimler dergisi, 2018
This study examined effects of birth year, herd type, age of dam, lamb sex, birth type and lamb color on birth weight in Hemsin lambs using the regression tree method. The study used the data obtained from 9113 Hemsin lambs born between 2007-2010. The average birth weight of Hemsin lambs was found to be 3.55 kg and the standard deviation was 0.727 kg. Significant differences were found in birth weights of Hemsin lambs according to birth year (P<0.001), birth type (P<0.001) and lamb sec (P<0.01), whereas no statistically significant difference was found according to herd type, age of dam and lamb color (P>0.05). According to the regression tree diagram, the most important factors affecting birth weight of Hemsin lambs were birth year, birth type, sex, herd type and age of dam. The absence of lamb color in the regression tree diagram indicates its insignificant effect on birth weight. The low risk value (0.456) and high R-Squared value (0.862) of the regression tree model shows that the model is sufficient to explain birth weight. Variables of birth year, birth type, sex, herd type and age of dam explained 86.2% of the variation in birth weight.
Crossbreeding of four Iranian fat-tailed sheep breeds, namely Kurdi (K), Chaal (C), Afshari (A) and Sanjabi (S) was carried out to determine the ram breed effects on productivity of Kurdi fat-tailed ewes (K) under extensive production system. A total of 475 Kurdi ewes were mated to 24 rams from the above four breeds resulting in 454 lambs. Ram breed had a significant influence on early growth traits of the lambs. Lambs sired by C rams were heavier than the other lambs (P< 0.05) at birth and weaning. Body weight at 160 days of age (W160) in crossbred lambs was significantly higher than that of the purebred lambs while crossbred lambs for W160 were similar (P> 0.05).Greasy fleece weight of lambs at first shearing (GFW) and fat-tail measurements were significantly affected by ram breed. Number of lambs born and number of lambs weaned per ewe lambed or per ewe joined were similar among the four groups, whereas there was significant effect on productivity. In general, ewes mated to Chaal ram had higher productivity than those mated to other ram breeds.
In order to investigate the changes in meat quality characteristics and some serum metabolites as well as carcass yield, non-carcass parts, internal organs of lambs as influenced by birth weight (BtW) and feeding system (FS), 28 Karayaka male lambs (150 days of age) obtained from four comparable groups that consisted of seven replicates according to a 2 × 2 factorial arrangement for 2 BtW (low, 4.1 ± 0.06 kg and high, 5.0 ± 0.09 kg) and 2 FS (total mixed ration, TMR and free choice feeding, FCF) were used. After weaning (90 days of age), lambs with low BtW and high BtW were fed individually a TMR ad libitum or fed on the same ingredients (FCF) as that of TMR. The TMR was consisted of 80% of a compound feed and 20% of roughage based on a dry matter basis (140 g crude protein and 10.7 ME MJ/kg). The carcass weight and yield of lambs were not affected by the BtW, FS and BtWxFS interaction. The slaughter body weight, cold carcass weight and yield of FCF-fed lambs were higher than those of TMR-fed animals. The pH 45 and shear force of semitendinosus muscle decreased and increased by the FCF systems, respectively. These results showed that BtW of lambs did not affect the studied parameter and that feeding system created more differences in terms of some parameters due to the fact that the FCF lead to improvement in carcass and some meat quality traits. ABSTRAK Dalam usaha untuk mengkaji perubahan dalam ciri kualiti daging serta sesetengah metabolit serum serta hasil bangkai, bahagian bangkai, organ dalaman biri-biri kerana dipengaruhi oleh berat kelahiran (BtW) dan sistem memberi makan (FS), 28 biri-biri jantan Karayaka (usia 150 hari) diperoleh daripada empat kumpulan perbandingan yang terdiri daripada tujuh replikat mengikut aturan faktoran 2 × 2 untuk 2 BtW (rendah, 4.1 ± 0.06 kg dan tinggi, 5.0 ± 0.09 kg) serta 2 FS (jumlah campuran catuan, TMR dan pilihan pemakanan bebas, FCF) telah digunakan. Selepas cerai susu (usia 90 hari), biri-biri jantan dengan BtW rendah dan tinggi diberi makan TMR ad libitum atau diberi bahan-bahan sama (FCF) seperti TMR secara individu. TMR tersebut terdiri daripada 80% sebatian makanan dan 20% hampas berdasarkan asas bahan kering (140 g protin gentian dan 10.7 ME MJ/kg). Berat bangkai dan hasil daripada biri-biri jantan tidak terjejas oleh interaksi BtW, FS dan BtWxFS. Berat badan penyembelihan, berat bangkai sejuk dan hasil biri-biri jantan diberi makan FCF adalah lebih tinggi berbanding haiwan diberi makan TMR. PH 45 dan ricih daya otot separa tendon menurun dan meningkat masing-masing mengikut sistem FCF. Keputusan ini menunjukkan bahawa BtW biri-biri jantan tidak menjejaskan parameter yang dikaji dan sistem pemakanan mewujudkan lebih banyak perbezaan daripada segi parameter yang disebabkan oleh FCF membawa kepada peningkatan dalam bangkai dan sebahagian sifat kualiti daging. Kata kunci: Berat organ; berat bangkai; daging biri-biri; pemakanan kafeteria; saluran penghadaman
Turkish Journal of Agriculture -Food Science and Technology
Measurements of the body structure in sheep are worthy of judging the quantitative features of meat and useful in developing appropriate selection requirements. The current study was aimed to predict live weight and hot carcass weight from linear body measurements of yearling male local sheep. 84 days feeding period fortnightly taken data on 24 local sheep for body weight, body length, heart girth, wither height, sub-sternal height, tail length, tail width, scrotal circumference, and scrotal length were analyzed to study the relationship between linear body measurements and body weight. At the end of the trial all sheep were slaughtered to measure the relationship between body measurements, and hot carcass weight. Microsoft Excel 2010 was used for data analysis. The relationships between the various body measurements were calculated using pearson's correlation coefficient. The backward stepwise multiple regression procedure was used for the determination of the most suitable model for the prediction of the live weight and hot carcass weight. Hot carcass weight was highly correlated (P<0.01) with body weight and scrotal circumference. Besides, it was significantly (P<0.05) correlated with tail width. Body weight was significantly (P<0.05) correlated with all body measurements except tail length and scrotal length. It is concluded that the body weight of the local sheep can be predicted with heart girth, sub-sternal height and tail width; the equation is LW=-97.2 + 0.36HG + 2.1SBSH + 0.57TW with a better coefficient of determination; R 2 = 0.55 and the hot carcass weight can be predicted with sub-sternal height and tail width; the equation is HCW=-75.66 + 1.75SBSH + 0.85TW with a coefficient of determination; R 2 = 0.33. But, hot carcass can be predicted with body weight, the equation is HCW=-9.39+0.85BWT when weighing scales are affordable with a better coefficient of determination; R 2 = 0.557.
Analysis of non-genetic and genetic influences underlying the growth of Kajli lambs
South African Journal of Animal Science
Data on 2931 Kajli lambs, born from 2007 to 2018, were used to quantify environmental and genetic effects on growth performance of Kajli sheep. Traits considered for evaluation were birth weight (BWT), 120-day adjusted weight (120DWT), 180-day adjusted weight (180DWT), 270-day adjusted weight (270DWT), and 365-day adjusted weight (365DWT). Fixed effects of year of birth, season of birth, sex, birth type, and dam age on these traits were evaluated using linear procedures of SAS, 9.1. Similarly, BWT, 120DWT, 180DWT, and 270DWT were used as fixed effects mixed model analyses. Variance components, heritability and breeding values were estimated by restricted maximum likelihood. The genetic trend for each trait was obtained by regression of the estimated breeding values (EBV) on year of birth. Analyses revealed substantial influence of birth year on all traits. Sex and birth type were the significant sources of variation for BWT and 120DWT. Season of birth did not influence birth weight ...
This study was conducted to investigate the pre-weaning growth of crossbreed types. Fifteen genotypes (F1 and B1) were obtained by crossbreeding in the Animal Research Institute in Konya from 1989 to 1996. These 15 genotypes were classified in 4 appropriate genotype names: Hasmer, Hasak, Hasiv and Linmer. GLM and Tukey's HSD tests were used for statistical analyses. Year, genotype, sex, birth type, and dam's age were introduced into the model as fixed factors and birth weight was introduced as a covariate along with year x genotype interaction. While the effects of year, damÕs age, birth type, and sex on birth weight were significant, the effects of genotype and year x genotype interaction were insignificant. The overall birth weight means were 4.29, 4.00 and 3.99 kg (P < 0.001) for 1997, 1998 and 1999, respectively. The differences between the genotypes were not significant, and the values were 3.95-4.19 kg for all genotypes during the 3-year experimental period. The birth weights of lambs from dams aged 3 years or older were higher than those of lambs with 2-year-old dams. The birth weights of ram lambs were higher than those ewe lambs, and single born lambs had higher birth weights than did twin born ones. The lambs were weaned at the age of 75 days. All factors except for dam's age and birth type affected the weaning weight. The weights of lambs at 75 days were 17.5-19.8 kg in 1997, 17.0-20.1 kg in 1998, and 19.5-22.5 kg in 1999, and the differences between genotypes were significant in all 3 years, although the superiority of some genotypes over others varied year by year. The year of weaning weights were significant in all genotypes expect for Hasiv , and the values obtained in 1999 were higher than those from 1997 and 1998. The same results were obtained in daily gains in the suckling period. The daily gains were 176-207 g in 1997, 170-212 g in 1998 and 203-243 g in 1999, and the values for 1999 were higher than those for the 2 previous years. The daily gains were 239, 231, 210, 203, 218, 241 and 243 g for the Hasmer, Hasak, Hasiv, Linmer, Merino, Akkaraman and Awassi breeds, respectively, in 1999 and the values for Hasiv and Linmer were lower than those for the other crossbreed types and the Akkaraman and Awassi breeds. In conclusion, the superiority of 1999 to 1998 and 1997 in terms of growth traits was observed not only in crossbred but also in purebred animals, and this may not be the result of selection but rather of an improvement in environmental factors. In general, the Linmer type exhibited a lower performance. Key Words: Mutton sheep breed, crossbreeding, selection, new sheep types, growth.
The increase in birth rate is one of the most important objectives in sheep breeding. One way to increase the birth rate and yield is to hybrid the weak native breeds with those of strong from the view point. To this aim, the study has investigated the effects of sex and weaning age on the first-generation lambs growth result according to ½Romanov and Zel. Also it has used the completely randomized factorial experiments with 6 treatment and 4 replication. The lambs weaning age has been 40, 50 and 75 days. The experimental diets have been the same to the all treatments in terms of energy, protein and other nutrients. The feed intake given to lambs has been measured and weighed with interval specification. By evaluating the feed consumption results and daily weighing, in 2 first weeks, as well as fourth and fifth weeks, there were significant differences have been observed in sex and weaning age (p<0.05). In the fourth 2 weeks, a significant statistical difference has observed in the feed conversion ratio (p<0.05). By result investigation, it has been observed that the male lambs have had better performances than the females in the term of feed consumption, feed conversion ratio and daily weight gaining during the experiment weeks. The lambs of 75 days have had the best performance in feed consumption and daily weight gain.