

Articles
by
Hulya Atil 
Total Records (
10 ) for
Hulya Atil 





Hulya Atil
,
M. Nagib El Ariain
and
A. Salah Khattab


673 records of Friesian heifers produced by 166 sires kept at a commercial
farm were used and the traits yield 90 days milk yield, 305 days milk
yield and annual milk yield were examined. Least squares analysis of variance
showed that the effect of sire as a random effect, year and season of
calving subclasses as a fixed effects and age at first calving (AFC)as
a covariate on most of different traits were significant. Curvilinear
of yield traits on age at first calving were obtained. A set of multiplicative
age correction factors of different traits were derived by fitting a polynomial
of second degree of production on age. Age correction factors had similar
trend and they did not exhibit large differences between consecutive ages
at older ages but relatively large differences between consecutive ages
at younger ages, differences in age correction factors were consistently
present across 305 days milk yield and each of 90 days milk yield and
annual milk yield and consequently factors used for adjusted 305 day milk
yield could be applied to different yield traits without substantial loss
in accuracy. 




Hulya Atil
and
Yakut Unver


Multiple comparison procedures allow
detecting differences among treatment means. These procedures include
pairwise, multiple comparisons, planned orthogonal and nonorthogonal
contrasts and orthogonal polynomials. In many situations the use of
multiple comparison procedure has been either appreciated or not the
most meaningful method of analysing the data. The objectives of many
animal experiments are to detect meaningful relationships among treatments
and associated responses and also to identify relationships among biological
responses. In this study, Least Significant Differences test, Student
NewmanKeuls test, Tukey test, Duncan test, Scheffe test, Hartley
test, Dunnet ttest, Bonferroni test, WallerDuncan test, William ttest,
confidence interval, orthogonal polynomials and orthogonal contrasts
are discussed. 




Hulya Atil
,
A. Salah Khattab
and
Cigdem Yakupoglu


A total of 5093 lactation records of
Holstein Friesian cows sired by 181 bulls kept at five herds in West
of Turkey during the period from 1972 to 1987 were used to estimate
phenotypic and genetic parameters for 305 day milk yield (305 dMY),
lactation period (LP) and days open (DO). In addition, sire transmitting
ability for these traits studied were also examined. Least squares analysis
of variance showed significant effect of herds, season of calving, year
of calving and parity on all traits studied, except the effect of season
of calving on lactation period. Including age at calving as a polynomial
regression of the second degree in the model yielded significant partial
linear and quadratic regression of 305 dMY on age at calving, while
the effect of age at calving on LP were not significant. In addition,
days open had a significant effect on 305 dMY and LP. Sires within herds
and cows within herds within sires were significant effect on most traits
studied. Heritability estimates were 0.38 + 0.06, 0.13 + 0.03 and 0.007
+ 0.02 for 305 dMY, LP and DO, respectively. All phenotypic and genetic
correlations among all traits studied were positive and significant
(P < 0.01), while, the genetic correlation between 305 dMY and DO
was negative. Sires with at least 10 daughters were evaluated by using
best linear unbiased prediction (BLUP), sire transmitting ability ranged
from 717 to 601 kg for 305 dMY, from 24 to 40 d for LP and from 5
to 6 d for DO. Sires give positive and higher BLUP values for 305 dMY
give positive BLUP values for LP and negative BLUP values for DO. 





Hulya Atil
and
Adel Salah Khattab


A total of 1931 normal first lactation records of Holstein Friesian cows kept at Dena Farm in Egypt during the period from 1987 to 1994 were used to estimate phenotypic and genetic parameters for 90 and 305 day milk yield (dMY) and lactation period (LP). In addition, 76 bulls with at least ten daughters were used to compare three methods of sire transmitting ability. A least squares analysis of variance show significant effect of month and year of calving and age at first calving for different traits studied, except the effect of age at first calving on LP. Heritability estimates for 90 and 305 dMY and LP were 0.39 ±0.08, 0.27 ±0.07 and 0.14 ±0.05, respectively. Genetic and phenotypic correlations between different traits were positive and significant. Sires with at least ten daughters were evaluated by best linear unbiased prediction, least squares means and regression of the future daughters mean on the present daughters mean. The product moment correlations between different traits studied were positive and high (= 0.96). 




Hulya Atil


A total of 2897 lactation records of Holstein Friesian cattle from the fields of Dena Farm in Egypt from 1987 to 1993 were used to study relationships of days open (DO) and days dry with milk production. The effect of month and year of calving, sire and cow within sires were also investigated. Month of calving, year of calving, sire and cow within sires significantly influenced milk production. Including DO and dry period (DP) as a polynomial of second degree of production were significant. The partial linear and quadratic regression coefficients of 305 day milk yield on DO and DP were significant being 7.59±0.40 kg/d and 0.37±0.00 kg/d^{2}, respectively for DO and 9.37±0.54 kg/d and 0.02±0.00 kg/d^{2}, respectively for DP. Therefore, reduction of DO and DP are a desirable goal of dairyman. Heritability (h^{2}) estimates for 305 day milk yield, DO, DP were 0.13±0.05, 0.00 and 0.00, respectively. Adjustment of lactation milk yield for DO will not involve genetic influence on milk yield. 




Hulya Atil
and
Adel Salah Khattab


Total of 3780 lactation records of Holstein Friesian cattle kept at a commercial farm (Dena Farm) in Egypt, during the period from 1988 to 1996 were used. Fixed effects of month and year of calving and age at calving as a regression and random effects of sire and cow within sire on 305 day milk yield were used. Least squares analysis of variance showed significant effects of month and year of calving, age at calving, sire and cow within sires. Including age at calving as a polynomial regression of the second degree in the model yielded significant regression coefficients. The partial linear and quadratic regression coefficients of age at calving on 305 day milk yield were 8.49 ± 1.76 kg/mo and 0.51 ± 0.05 kg/mo^{2}, respectively. A set of multiplicative age factors was derived for 305 day milk yield for each season of calving and for all data by fitting a second degree polynomial for production on age. It is suggested that there should be a separate set of age correction factors for each season of calving and for each region. 




A. Salah Khattab
,
M. Nagib El Ariain
and
Hulya Atil


A total of 3236 lactation records of 929 Holstein Friesian cattle sired by 290 bulls kept at a commercial herd in Egypt (Dalla Farm) were used. Cows transmitting abilities (CTA) were estimated by best linear unbiased prediction (BLUP). All cows whose at least two records up to six were used. Means of 90 day milk yield (90 dMY) and 305 day milk yield (305 dMY) are 1673 to 25 and 5076±64 kg, respectively. Least squares analysis of variance showed a significant effect of month of calving, year of calving and parity as fixed effects and sire and cow within sire as random effects on 90 dMY and 305 dMY. Heritability, repeatability, genetic and phenotypic correlations were estimated by paternal half sibs correlations. Heritability estimates were 0.31 to 0.06 and 0.15±0.05 for 90 dMY and 305 dMY, respectively. Repeatability estimates were 0.25 ti 0.02 and 0.34±0.02 for 90 dMY and 305 dMY, respectively. Genetic and phenotypic correlations between the two traits studied were 0.47±0.12 and 0.53, respectively. Estimates of CTA for 90 dMY ranged from 513 to 556 kg and from 989 to 1754 kg for 305 dMY with the range being 1069 and 2743 kg, respectively. Product moment correlation between 90 dMY and 305 dMY was 0.92. The present results indicated that CTA for 90 dMY was good predictor of CTA for 305 d MY. 




Hulya Atil


A total of 2133 normal lactation records of Holstein Friesian cows raised at five herds in Turkey, during the period from 1982 to 1998 were used in this study to estimate phenotypic and genetic parameters for 305 day milk yield (305 dMY), Lactation Period (LP) and Age at First Calving (AFC). In addition, four selection indices were constructed by using one standard deviation as a relative economic weight. Least squares analysis showed significant effects of herds, sire within herds, year and moth of calving on all traits studied (p<0.01), except the effect of year and month of calving on LP. Heritability estimates were 0.47, 0.18 and 0.53 for 305 dMY, LP and AFC, respectively. Genetic and phenotypic correlations among 305 dMY and LP were positive and highly significant, while, other correlations were small. Four selection indices were constructed, index I1 incorporating 305 dMY, LP and AFC was the best (R_{IH} = 0.77) and it is recommended if the selection was exercised at the end of the first lactation. In addition, using one standard deviation as relative economic values is easy in estimation and small differences between this method and actual economic values. 




M. Nagib El Ariain
,
Hulya Atil
and
A. Salah Khattab


Least squares analysis of variance showed significant on month of calving, year of calving and parity on all traits studied (p<0.05 or p<0.01) except for the effect of year of calving on lactation period. The effect of group was significant on DP and DO (p<0.05 or p<0.01). The effect of sire was significant on 305 day milk yield and heritability estimates was 0.203±0.064. The present results show that local born are produced less milk and smaller LP, DP, DO and CI than their imported dams. Then it is adapt Holstein Friesian in Tropical countries. Improving the management in the farm may result in better performance especially in reproductive traits. 




Hulya Atil
and
Yakut Unver


Achievement in experiments based on properly design product. In some cases, it is necessary to study on a lot of combinations of experiment. This is difficult to apply it for user and it needs more time. The Taguchi method of design of experiments is a statistical tool based on the systematic approach of conducting minimal number of experiments using orthogonal arrays. Traditionally, this method has been used to predict the significant contribution of each design variables and the optimum combination of the design variables by conducting a real time experiment. In this study, Taguchi Methods having more advantages than real time experiments is determined. 





