There are many indigenous cattle breeds in iran among which Najdi breed adapted in the south. This breed is recognized by light-brown color and a hump in their withers area. There was no information about hematologic profile of this breed. Therefore, this study was carried out in order to determine the hematologic profile of this breed in hot and cold seasons with respect to age and sex. In this study, hematologic factors of 200 Najdi cattle in different age and sex groups were determined by conventional laboratory methods. The levels of RBC, PCV and MCV were higher in cold season and the levels of MCR, WBC, monocytes, eosinophiles and basophiles were higher in hot months (P<0.05). The levels of RBC, Rb, PCV and lymphocyte were higher in male and eosinophiles and MCV were higher in female (P<0.05). In different age groups, there were significant differences in the levels of RBC, Rb, PCV, MCV, MCR, MCRC, WEC and eosinophiles (P<0.05).  

The objective of this study was to evaluate the performance of genomic selection for milk yield, fat percent and protein percent in Najdi cattle breed from station and Agmari herds using different statistical models. Traditional estimated breeding values obtained with a random regression model using pedigree and phenotypic information for each trait from 1990 to 2016 were used as response variables. Predictability was evaluated by using a 10 replicated Training-Testing scheme and considering four models including genomic best linear unbiased prediction scaled with observed allele frequency (GBLUP), and allele frequency of 0. 5 (G05BLUP), BayesA and BayesB. The results showed that GBLUP had better performance than G05BLUP for milk yield (0. 411 vs 0. 385), but performance of G05BLUP was better for fat percent (0. 257 vs 0. 302) and protein percent (0. 363 vs 0. 388). The accuracy of breeding values of milk yield decrease to 0. 371 and 0. 353, and accuracy of fat percent increased to 0. 329 and 0. 314 with BayesA and BayesB, respectively. Bayesian methods had same accuracy as GBLUPs for protein percent. Across traits and methods BayesA with 0. 14 for protein percent, and G05BLUP with 0. 71 for milk yield had smallest and highest bias as deviate from 1, respectively. Accuracy of prediction using Agmariherds in addition station herd increased 0. 01 to 0. 09 depending on method and trait, but also bias were more than before. In conclusion, accuracy of genomic prediction of milk traits in Najdi cattle breed are moderate but suitable considering small size of population which makes genomic selection feasible in this breed.

One of the native cattle in Khuzestan province of Iran is Najdi breed that is characterized by a hump in the withers area. As there is no information available about blood electrolytes of this breed in Khuzestan province, this study was carried out to determine the blood electrolytes of Najdi cattle in hot and cold seasons with respect to age and sex. Therefore, blood electrolytes of 180 Najdi cattle in different age and sex groups were determind by conventional laboratory methods. Serum calcium and phosphorous in female animals were affected by season, so that serum calcium and phosphorous levels were higher significantly in summer and winter, respectively (P<0.05). Serum phosphorous concentrations of adult female animals were significantly lower than immature animals, but calcium was not affected by age, and also sex. They had no effects on serum calcium and phosphorous. The serum concentration of sodium was higher in summer only in immature animals. In summer, adult female animals had lower concentrations of sodium in comparison with immatures but, sodium was not affected by sex. The serum potassium levels of females, with more than 6 months of age, in summer were higher than winter season, but potassium was not affected by age and sex. The serum chloride concentrations of animals, with more than 6 months of age, in winter were higher than summer. Female animals with more than 6 months of age had higher concentrations of chloride. Female calves had higher serum chloride levels than males (P<0.05).

The present study was carried out to estimate levels of genomic inbreeding based on ROH (FROH) analysis in the two Iranian native cattle populations including Sarabi and Najdi, as well as comparing the FROH estimates with other inbreeding estimates obtained based on the genomic relationship matrix (FGRM), percentage of homozygous SNPs (FHOM) and pedigree information (FPed). To do this, 213 and 211 samples were randomly selected from Sarabi and Najdi populations, respectively. The samples were genotyped using the Illumina BeadChip40K v2 microchip. In addition, 30 samples of Holstein dairy cattle of Iran provided by Animal Breeding Center of Iran, were included in the analysis. Genomic analysis was performed using CFC, Excel, Plink, SNeP programs. A total of 2030 haplo-blocks were identified in the populations. The highest and lowest number of ROH segments (ROHs) was observed within Najdi and Sarabi Population, respectively. Furthermore, ROH length were found to be significantly different among breeds (p < 0. 05). Najdi population had the highest number of ROH across different categories of ROH length (4-8Mb, 8-16Mb and >16Mb). Maximum correlation coefficient among the estimated inbreeding coefficients was obtained between FPed and FROH>4Mb (0. 592) in the Sarabi population (p < 0. 001). The results of this study indicate that presence of inbreeding at least in the five early generations of the studied native populations and the conservation programs must be taken to manage the inbreeding levels in both populations.

The objective of this study was to determine the polymorphism of bovine b-lactoglobulin (b-LG) gene and its association with milk production traits in Iranian Najdi cattle. Blood samples were collected from 80 Najdi cattle from the Najdi cattle breeding station located in Shoshtar, Khuzestan. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniqus were used for identification of various genotypes. The results indicated that allele frequency of b-LG with regard to the B-allele (0.9125) was higher than that of the A-allele (0.0875). Frequencies of AB and BB genotypes were 0.175 and 0.825, respectively, while the AA genotype was found to be absent. Genotype frequencies were in accordance with the Hardy-Weinberg equilibrium. The effect of b-LG genotypes on milk production traits were analysed using a general linear model (GLM). There was no significant association between different genotypes of b-LG and milk production traits of the analysed cows.

To determine the best function for describing lactation of Najdi cow in Khuzestan, the day-based milk production test records, collected by Shushtar support station from 1990 to 2014, were used. Records included 2369 data related to 444 first parity cows. To determine the best mathematical function, six functions includind incomplete gamma, wilmink, inverse polynomial, complex logarithmic, Cobby and Le Du, and polynomial regression were evaluated. All functions were fitted using PROC NLIN procedure of SAS software and Gauss-Newton iteration method on day-based milk production test records; and compared based on coefficient of determination R2, corrected coefficient of determination, the mean square error and Akaike index. The results showed that the inverse polynomial function offers a better description for lactation curve in Najdi cattle.  The lactation curve parameters (a, b, c) were estimated 4.4841, 0.2514, 0.00273, and their heritability were 0.354±0.120, 0.280±0.11 and 0.276±0.155, respectively. Moderate heritability suggests the opportunity of genetic response via selection program. Heritability of these traits can be improved by correcting the known environmental impacts.

More than 80% of the total milk protein contains caseins that are to forms a-s1, a-s2, b-casein and kappa casein. Kappa casein is smaller than other milk proteins but due to have a role in size and stability of micelles. The present study describes polymorphism of kappa casein gene. This is the first study of kappa casein gene polymorphism in Najdi cattle of Iran. We used the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique to screen DNA polymorphism in cattle. We amplified the 453 fragment consisting on part of exon 4. The amplified fragment was digested with HinfI restriction endonuclease and subjected to electrophoretic separation in 3% agarose gel. Two alleles were observed, A and B. It gives frequencies of 0.54 and 0.46 for A and B alleles. Also, genotypes AA, AB and BB with frequencies of 35%, 37.5% and 27.5% of the total study population were diagnosed. Existence of HardyWeinberg equilibrium indicated that there was not any choice in order to increase or decrease the frequency of genotypes in the kappacasein population in this herd. Also, in this population kappacasein gene has medium level of heterozygosity.

In order to identify the signatures of selection in three Iranian native cattle and Holstein breeds, genomic information of 153 native cattle (including 63 Sarabi, 44 Najdi and 46 Taleshi) and 60 Holstein cattle and 46 Brahma cattle (as an outgroup breed) were used. In order to determine the genotype of the samples, Illumina Bead Chip 40K (for native breeds) and Illumina Bead Chip 770K (for Holstein and Brahman breeds) were used. The genomic information of foreign breeds was extracted from the WIDDE database. After the quality control of the data, hapFLK statistical method with hapFLK v1.4 software was used to identify selection signatures. Considering the high hapFLK value of 0.1%, selection signatures were identified using the Ensmble Biomart tool, which included 57 genes on chromosome 25. Then, using the PANTHER database, the general biological function of the genes was checked, and the QTLs in the selected region were extracted using the Animalgenome database, and the genes were compared with other researches.The results showed that these genes were associated with different biological pathways such as ATP-dependent activity, binding, catalytic activity, molecular adapter activity, molecular function regulator, molecular transducer activity, transcription regulator activity and transporter activity.The QTLs reported in these areas were also related to the traits of stature and withers hight, milk yield and contents, muscle iron content, body weight and calving ease traits.

In order to estimate variance components, 8843 test day milk and fat yields records: from first lactation Najdi cattle were used. Data were obtained between years 1989-2005 by Animal Breeding Station of Najdi Cattle located in Shooshtar. Random regression models were studied in respect with different orders of fitting for fixed and random regression. Also, different methods of residual variance in the analysis including assumption of constant residual variance and different assumption about variable residual variance during lactation were assumed. According to the results, the assumption of heterogeneous residual variance during lactation improved characteristics of the statistical model. A suitable model with (3, 3) orders of fit for additive genetic and permanent environmental covariance functions to analyze TD fat and milk yield records were recognized. Minimum of heritability for fat and milk yield was estimated at the beginning of lactation, (0.1, 0.15), respectively. The amount of this parameter increased to mid lactation and almost in the 5thmonth of lactation reached the maximum level (0.34 for milk yield and 0.44 for fat yield), then decreased to the end of lactation. Minimum and maximum of genetic and permanent environmental correlation were estimated between 5 and 270 days of lactation.

Objective: Identity the genetic aspects and major gene influence on energy balance, milk production, fertility, food safety and consumer are the recent interests of genetic and breeding researchers.Methods: Najdi Cattle is the most prominent breeds in Khuzestan province. To do this plan in Shoushtar Najdi Cattle Station, blood samples were taken from 15 Najdi Cattles. DNA was extracted from whole blood using the method of Boom et al and polymerase chain reaction took for amplification of two fragments 544 bp and 566 bp. After ensuring the accuracy of the duplicated sequences on 1% agarose gel, sequencing was performed and the Leptin gene promoter components pointed out in Najdi Cattle. In this study, the six mutations identified in the first fragment 566 bp. In these mutations, 2 types of them were point mutations including Transition and Transversion, and 4 mutations were Frame shift which included Deletion (3kinds) and Insertion (1kind). In the second fragment 544 bp, 2 point mutations (transition and Transversion) and 1 Frame shift mutation (deletion) were appeared, in the Leptin gene pro-motor region. Also, in this study, the sequences related to each sample was compared in the two fragments in the aspect of similarity with other documented sequences, that BLAST results showed that high percentage of similarity.Results: According to the obtained results, it could be said that the sequence of leptin gene of Najdi cattle in Khuzestan province is similar to other documented sequences and there are a high-similarity percentage between current samples’ sequences and those documented in global information bank.