Mammary fat globules as a source of mRNA to model alterations in the expression of some milk component genes during lactation in bovines.

BACKGROUND: The milk's nutritional value is determined by its constituents, including fat, protein, carbohydrates, and minerals. The mammary gland's ability to produce milk is controlled by a complex network of genes. Thereby, the fat, protein, and lactose synthesis must be boost in milk to increase milk production efficiency. This can be accomplished by fusing genetic advancements with proper management practices. Therefore, this study aimed to investigate the association between the Lipoprotein lipase (LPL), kappa casein CSN3, and Glucose transporter 1 (GLUT1) genes expression levels and such milk components as fat, protein, and lactose in different dairy breeds during different stages of lactation. METHODS: To achieve such a purpose, 94 milk samples were collected (72 samples from 36 multiparous black-white and red-white Holstein-Friesian (HF) cows and 22 milk samples from 11 Egyptian buffaloes) during the early and peak lactation stages. The milk samples were utilized for milk analysis and genes expressions analyses using non- invasive approach in obtaining milk fat globules (MFGs) as a source of Ribonucleic acid (RNA). RESULTS: LPL and CSN3 genes expressions levels were found to be significantly higher in Egyptian buffalo than Holstein-Friesian (HF) cows as well as fat and protein percentages. On the other hand, GLUT1 gene expression level was shown to be significantly higher during peak lactation than early lactation. Moreover, lactose % showed a significant difference in peak lactation phase compared to early lactation phase. Also, fat and protein percentages were significantly higher in early lactation period than peak lactation period but lactose% showed the opposite pattern of Egyptian buffalo. CONCLUSION: Total RNA can be successfully obtained from MFGs. The results suggest that these genes play a role in glucose absorption and lactose synthesis in bovine mammary epithelial cells during lactation. Also, these results provide light on the differential expression of these genes among distinct Holstein-Friesian cow breeds and Egyptian buffalo subspecies throughout various lactation phases.

Principal component analysis of phenotypic and breeding value data for semen traits in Egyptian buffalo bulls.

Buffalo bull semen traits are economically important traits that influence farm fertility and profitability. Genetic improvement of semen characteristics is an important detail of the genetic improvement. This study was conducted to assess the relationship between the breeding values as well as the phenotypic values for semen traits (VOL, MM, LS, AS and CONC) of the Egyptian buffalo bulls. A total of 7761 normal semen ejaculates were collected and characterized at ILMTC laboratory from 26 bulls from 2009 to 2019. For VOL, MM, LS, AS, and CONC, the actual means were 3.89 mL, 62.37%, 60.64%, 3.94%, and 0.67 × 109 sperm/mL, respectively. The prediction of breeding values for semen traits was estimated using a Bayesian procedure. The estimated standardized EBVs and phenotypic values were used in the principal component analysis (PCA). Of five PCs, one PC (PC1) had > 1 eigenvalues that was responsible for 87.19% of the total variation of SEBV, and two PCs had > 1 eigenvalues that were responsible for 59.61% and 21.35% of the total variation of the phenotypic values. Together, PC1 and PC2 accounted for 97.97% of the total variance of SEBV and 80.96% of the total variance of phenotypic values. A graphs of the first two components showed the traits separated into two different directions by group. This indicates each group was under similar genetic influence. Therefore, selection can be done separately for each group without influencing the other. Principal component analysis reduced variables to describe the key information in buffalo semen data.

Estimation of genetic parameters for semen traits in Egyptian buffalo bulls.

This study was conducted to characterize semen traits (ejaculate volume (VOL), mass motility (MM), sperm livability (LS), percentage of abnormal sperms (AS), and sperm concentration (CONC)) of Egyptian buffalo bulls and evaluate the importance of some nongenetic factors (year (YC) and season (SC) of semen collection and age of bull genetically and environmentally at collection (ABC)) affecting the investigated traits. A total of 7761 normal semen ejaculates were collected from 26 bulls from 2009 to 2019. Single-trait and bivariate repeatability animal models using Bayesian methods were used to estimate variance components, heritability, repeatability, and genetic correlations among the investigated semen traits. YC and ABC exerted significant effects on most semen traits, whereas SC exerted no significant effect on all the investigated semen traits. Heritability estimates were 0.08, 0.52, 0.51, 0.04, and 0.49 for VOL, MM, LS, AS, and CONC, respectively. Repeatability estimates were 0.14, 0.82, 0.79, 0.06, and 0.78 for VOL, MM, LS, AS, and CONC, respectively. The genetic correlations between MM and each of LS and CONC were highly significant (0.99 ± 0.01 and 0.95 ± 0.14, respectively), and that between LS and CONC was also highly significant (0.92 ± 0.20). The high heritability estimates for MM, LS, and CONC combined with the favorable high significant genetic correlations between these traits indicated that direct selection for MM may be an effective method to enhance semen quality in Egyptian buffalo bulls and consequently improve fertility.

Light and scanning electron microscopic characterization of the Egyptian buffalo hair in relation to age with analysis by SEM-EDX.

The purpose of this study was to demonstrate a relationship between the microstructure and measurements of Egyptian buffalo hair and age. The buffalo studied ranged in age from young to premature to adult (3-8 months, 1.5-3, 4-6, and 8-10 years). The hair was collected from the animals' withers. Cuticle elements were examined using scanning electron microscopy (SEM), light microscopy, and energy-dispersive X-ray (EDX) analysis. Hair shaft diameter increased with age, according to SEM and light microscopy measurements. The values of shaft diameter obtained by SEM of the same animal were 64%-67% of the values obtained by light microscopy due to shrinkage of the hair during the drying process. Additional microscopy measurements revealed that the width of the cortex and medulla increased with age, while the width of the cuticle decreased slightly. The medulla index of four different age groups ranged from 0.56 to 0.61 µm. The average distance between successive scale values increased from 4.83 µm in the young group to 8.86 µm between the ages of 8 and 10 years. The scale pattern had a distinct personality at each stage of age. The hair medulla was in the center and consisted of a mesh-like structure with large pores divided into smaller pores by septa. The cortex was a bundle of fibers that wrapped around the medulla. Light microscopy revealed small oval granules and large streak-like granules in the cortex. EDX spectra revealed that carbon, oxygen, and nitrogen were shown to be more abundant in all age groups of buffalo. In buffalo hair, oxygen was the second most abundant element after carbon. The carbon mass in the examined samples decreased slightly with age (42.31%, 39.18%, 38.88%, and 38.49%), while oxygen increased with age. We concluded that hair measurements varied with age, scale microstructure, and elements, so we estimated buffalo animals' ages up to 10 years. HIGHLIGHTS: The goal was to show a link between the microstructure and measurements of Egyptian buffalo hair and age. Hair shaft diameter increased with age, according to scanning electron microscopy (SEM) and light microscopy measurements. The hair shaft diameter obtained by light microscopy was higher than that obtained by scanning electron microscopy of the same animal; we hypothesized that the difference in hair shaft diameter measured by light microscopy and scanning electron microscopy of the same animal was due to the shrinkage of the hair during the drying process. The width of the cortex and medulla increased with age, while the width of the cuticle decreased slightly. The average distance between successive scale values increased from 4.83 µm in the young group to 8.86 µm between 8 and 10 years old. At each stage of age, the scale pattern had a distinct personality. Carbon, oxygen, and nitrogen were found to be more abundant in the hair of buffalo of all ages and were detected using energy-dispersive X-ray (EDX) spectra. After carbon, oxygen was the second most abundant element in buffalo hair. The carbon mass in the samples studied decreased slightly with age, while the oxygen mass increased. Hair measurements varied according to age, scale microstructure, and elements.

Association analysis of prolactin and prolactin receptor genes with selected productive and reproductive traits in Egyptian buffalo.

A total of 266 records of buffalo raised in two experimental herds in Egypt were assessed to detect prolactin (PRL) and prolactin receptor (PRLR) genes' polymorphism using PCR-Single Strand Conformational Polymorphism (SSCP) and PCR-Restricted Fragment Length Polymorphism (RFLP) techniques as well as to investigate their association with calf birth weight (BW), weaning weight (WW), lactation period (LP), total milk yield (TMY), stillbirth, calving ease (CE), gestation length (GL), postpartum interval to pregnancy (PPIP), calving interval (CI), and age at first calving (AFC). Predicted breeding values were estimated and used in the association with detected genotypes. A monomorphic pattern of the studied PRL 156 bp segment was recorded and absence of its polymorphism in buffalo was corroborated. We also determined polymorphism of PRLR reflected in three loci: PRLR2, PRLR4, and PRLR9. Significant differences among PRLP9 genotypes (AA, AB, and BB) were displayed for all studied traits as well as among PRLR2 genotypes, except for CE, while PRLR4 genotypes significantly differed only in BW, WW, TMY, stillbirth, GL, and AFC. In practice, strong associations among genotypes of the PRLR gene and the traits of interest candidate this gene to be selective in Egyptian buffalo breeding for improving both productive and reproductive traits.

Genetic parameters of production and reproduction traits of Egyptian buffaloes under subtropical conditions.

This research was aimed to investigate the production and reproduction traits and their genetic parameters of Egyptian buffaloes under subtropical environment. Heritability, phenotypic, and genetic parameters were estimated for productive and reproduction traits of first parity This study revealed the averages TMY, 305-dMY, LL, BW, DP, SP, CI, and AFC were 2260, 2150 kg, 271 days, 38.63 kg, 210.50 days, 195.20 days, 586.86 days, and 36.61 months, respectively. The heritability estimates for productive traits of the first lactation were 0.61, 0.52, 0.47, 0.20, and 0.23 for TMY, 305-dMY, LL, DP, and BW, respectively. Heritability estimates for reproductive traits SP, CI, and AFC were 0.07, 0.09, and 0.35, respectively. Genetic correlations of most of the investigated first parity traits were positive, with an exception of DP. The genetic correlation was negative between SP and BW, and between AFC and LL. Phenotypic correlations of the first parity among all investigated traits were positive except between DP and TMY, 305-dMY, LL, BW, and AFC. High and moderate heritability estimates indicated that the opportunity of genetic upgrading of these parameters could be achieved owing to sire selection. Selection for high milk yield will be associated with genetic improvement in lactation period and birth weight.

The Association of the Potential Risk Factors and Nutrition Elements with Abortion and Calving Rates of Egyptian Buffaloes (Bubalus bubalis).

The aim of the present study was to investigate risk factors, serum minerals, and metabolites associated with non-infectious abortion and calving rates of Egyptian buffaloes. Data were obtained from 364 pregnant buffaloes of different ages and parities over 7 years from 2014 to 2020. Body condition score (BCS) was a risk factor regarding abortion and calving; the thinnest buffaloes were more likely to abort and less likely to calving than those with body energy reserves. In comparison with the spring season, aborting probability decreased 49.7% the odds ratio (OR = 0.503), while the chance of calving increased 72.1% (OR = 1.721) during winter. The parity was another significant factor related to abortion and calving rates; multiparous buffaloes were less likely to abort and more likely to calving than primiparous. Dry buffaloes had 88.2% (OR = 0.118) lesser odds of abortion and six times (OR = 6.012) more likely to give birth than those lactating. The sex of the fetus was not a risk factor regarding abortion or calving. Other variables significantly associated with abortion rate were glucose and copper in the sera of aborted buffaloes were significantly higher (p < 0.05), and those of urea, uric acid, total protein, total cholesterol, phosphorus, magnesium and iron were significantly (p < 0.05) lower than a normal pregnancy. In conclusion, the present results emphasize that the identification of the risk factors, serum minerals and metabolites associated with fetus abortion of Egyptian buffalo may provide useful information, which assists to construct suitable preventive measures to raise reproductive performance.

Polymorphisms of the PRLR Gene and Their Association with Milk Production Traits in Egyptian Buffaloes.

Prolactin (PRL) and its receptor (PRLR) were considered as potential genetic markers for milk production and quality traits in cattle. However, little information is available regarding PRLR genetic diversity and association studies with milk traits in Egyptian water buffaloes. Therefore, the present study was conducted to search for mutations in PRLR and determine their associations with milk performance in these animals. Exon3 (E3) and E10 of PRLR were screened for polymorphisms using single strand conformation polymorphism (SSCP) and sequencing in 400 buffaloes. The associations between haplotypes and milk production (fat%, protein%, lactose%, and solid%) traits as well as mRNA and protein levels of PRL and PRLR were studied. Two single nucleotide polymorphisms (SNPs) in E10 were detected: g.11685G>A (p.Ala494Thr) and g.11773T>C (p.Val523Aal). The G and T alleles were wild (ancestral) alleles, while the A and C alleles were mutant alleles. These SNPs resulted in four haplotypes; AC, AT, GC, and GT. Buffaloes with wild GT haplotypes showed significantly higher milk yield, fat% and protein%, mRNA and protein levels of PRL and PRLR in milk somatic cells than other animals. Animals carrying mutant AC haplotype had inferior milk traits and lowest levels of associated mRNAs and proteins. With these results, we could conclude that the selection of buffaloes with wild GT haplotypes for g.11685G>A and g.11773T>C SNPs of the PRLR gene might improve the milk production traits of Egyptian water buffaloes.

Effect of Quercetin Supplementation in Extender on Sperm Kinematics, Extracellular Enzymes Release, and Oxidative Stress of Egyptian Buffalo Bulls Frozen-Thawed Semen.

Buffalo spermatozoa are more sensitive for cryopreservation compared to other species. This study aimed to evaluate the consequences of quercetin against cryodamage of buffalo frozen-thawed spermatozoa characteristics. Semen of Egyptian bulls (n = 4) was extended in OptiXcell extender incorporated with quercetin at 0 (control), 2.5, 5.0, 10.0, 20.0, 40.0, and 80.0 µM before cryopreservation. Frozen-thawed semen was evaluated for sperm motility by computer-assisted sperm analyzer (CASA), viability, morphology, membrane, and acrosome integrities. The kinematics parameters including average path velocity (VAP; µm/s), straight linear velocity (VSL; µm/s), curvilinear velocity (VCL; µm/s), amplitude of lateral head displacement (ALH; µm), beat cross frequency (BCF; Hz), linearity [LIN, (VSL/VCL) × 100], and straightness [STR, (VSL/VAP) × 100] were assessed. The sperm-free extender was evaluated for aspartate aminotransferase (AST), alanine aminotransferase (ALT), and H2O2. Homogenized sperm cells were evaluated for oxidative stress biomarkers [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX)], and lipid peroxidation [malondialdehyde (MDA)]. The highest values of total motility, progressive motility, viability, intact acrosome, and membrane integrity substantially improved with 10 µM of quercetin. STR (%) was substantially low (P < 0.01), and VCL (µm/s) and ALH (µm) were markedly high (P < 0.05) in 10 µM of quercetin. The outflow of ALT enzyme to extracellular fluid was lower with 10 µM of quercetin (P < 0.001) and higher at 2.5 µM of quercetin. The spermatozoa leaked AST was markedly lower at 5.0, 10 (P < 0.001) and 20 µM (P < 0.05) of quercetin. The activity of antioxidant enzymes was eminently low at all quercetin concentrations, and this was accompanied by the decrease in H2O2 in the media. SOD activity at 10-80 µM, CAT at 5.0-40 µM, and GPX at 2.5-80.0 µM of quercetin in spermatozoa were substantially low. MDA level significantly (P < 0.001) decreased at all quercetin concentrations. In conclusion, the incorporation of quercetin at the level of 10 µM is promising in improving buffalo semen characteristics and lower the freezing-thawing oxidative stress.

Cardiac troponin I as a cardiac biomarker has prognostic and predictive value for poor survival in Egyptian buffalo calves with foot-and-mouth disease.

BACKGROUND AND AIM: Foot-and-mouth disease (FMD) causes huge economic losses in Egypt due to reductions in the production of red meat, milk, and milk by-products and can also lead to myocarditis in young animals. The aim of our study was to evaluate cardiac biomarkers, in particular cardiac troponin I (cTnI), and to reveal the relations of cardiac biomarkers with poor survival in FMD-infected Egyptian buffalo calves. MATERIALS AND METHODS: Forty-two Egyptian buffalo calves were included in this study. The calves were divided into 12 apparently healthy control calves and 30 calves clinically diagnosed with FMD during a disease outbreak in Menofia and Behera Governorates, Egypt. The diseased calves were divided, according to age, into 13 calves <3 months old and 17 calves between 3 and 6 months old. The animals were examined clinically and subjected to analysis of cardiac biomarkers. RESULTS: Biochemical analysis revealed significant elevations of cardiac biomarkers, especially creatine kinase myocardial band (CK-MB), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), cardiac troponin T (cTnT), and cardiac troponin I (cTnI) in FMD-infected calves in comparison with control calves. There was a significant association between cTnI and poor survival in infected calves. CONCLUSION: Cardiac biomarkers could be used as a rapid method for diagnosis of myocarditis induced by FMD in Egyptian buffalo calves. In addition, cTnI is a very sensitive and accurate tool for determining myocardial cell damage in the earlier stages of the disease and a good predictor of poor survival in calves.

Establishment a protocol for total RNA isolation from buffalo fresh and frozen semen for molecular applications.

To date, there is no an established protocol for total RNA isolation in Egyptian buffalo spermatozoa. The present study aimed (I) to establish a defined protocol for total RNA isolation from fresh and frozen spermatozoa, (II) to evaluate RNA quality and quantity from different extraction methods and studying gene expression. Warm and standard room temperature modified QIAzol Lysis Reagents were used for total RNA extraction. The quality and quantity of extracted RNA were checked, and subsequently qRT-PCR was performed using androgen receptor-like and three reference gene primers (GAPDH, ACTB and 18S). The warm modified QIAzol Lysis Reagents resulted higher yield of good quality RNA from fresh (569.54 ± 18.83 ng/µl) and frozen spermatozoa (110.59 ± 4.43 ng/µl), compared to standard room temperature modified QIAzol (421.26 ± 7.18 ng/µl) and (29.07 ± 5.25 ng/µl), for fresh and frozen semen samples respectively. The 260/280 ratio was 1.90 and 1.89 for fresh and frozen isolated semen by warm method respectively. The integrity of RNA was good and appeared as a sharp band on 2% agarose gel. The most stable reference gene was 18S. Reliable extraction method of high quality RNA yield could be a step forward for understanding mechanisms of spermatogenesis for improving male fertility.

Epidural anesthesia in Egyptian water buffalo (Bubalus bubalis): a comparison of lidocaine, xylazine and a combination of lidocaine and xylazine.

OBJECTIVE: To evaluate and compare the analgesic effects of a combination of lidocaine and xylazine to lidocaine or xylazine administered alone for epidural anesthesia in Egyptian water buffalo (Bubalus bubalis). STUDY DESIGN: Prospective, randomized, 'blinded', crossover experimental study. ANIMALS: A total of 12 female Egyptian water buffalo. METHODS: Buffalo were randomly assigned to one of three epidural treatments administered through the sacrococcygeal joint: a local anesthetic (2% lidocaine, 0.22 mg kg-1), an alpha-2-adrenergic agonist (xylazine, 0.1 mg kg-1) or a combination of both drugs in a crossover fashion with a 14 day washout period. The total volume of each treatment was fixed at 7.0 mL by adding 0.9% NaCl. Onset, maximal effect, and duration of epidural anesthesia were recorded. RESULTS: Caudal epidural anesthesia was easily performed, and all three treatments produced local anesthesia of the tail and perineal structures of standing buffalo. Onset of epidural anesthesia was faster (p < 0.05) with lidocaine (3.4 ± 0.9 minutes) than with xylazine (9.1 ± 1.1 minutes) or lidocaine-xylazine (6.4 ± 1.1 minutes). The maximal effect of epidural anesthesia was reached faster (p < 0.05) with lidocaine (5.9 ± 0.64 minutes) than xylazine (14.4 ± 1.1 minutes) or lidocaine-xylazine (12.9 ± 0.64 minutes). The duration of epidural anesthesia was longer (p < 0.05) with lidocaine-xylazine (145.8 ± 3.3 minutes) than either lidocaine (118.4 ± 2.7 minutes) or xylazine (102.1 ± 3.7 minutes) administered alone. None of the treatments produced ataxia. CONCLUSIONS AND CLINICAL RELEVANCE: Caudal epidural anesthesia was easily performed in Egyptian water buffalo by administering a local anesthetic, an alpha-2-adrenergic agonist or a combination of both drugs through the sacrococcygeal joint. Administering a combination of lidocaine and xylazine provided a longer duration of anesthesia than either drug used alone. Epidural xylazine provided a useful level of systemic sedation without ataxia.

Effect of some genetic and non-genetic factors on productive and reproductive traits of Egyptian buffaloes.

OBJECTIVE: The objectives of our study were to estimate the effect of some non-genetic factors on production and reproduction traits of Egyptian buffaloes and to estimate the breeding values for these traits. MATERIALS AND METHODS: Data from 965 lactation records of 305 Egyptian buffalo cows mated by 73 sires that were raised at Mahallet Mousa Experimental farms of Animal Production Research Institute were collected. Dairy records covered the period from 2001 to 2015. The data were arranged and statistically analyzed using SAS version 9.1.3 to study the effect of non-genetic factors and the MTDFREMAL program was included in estimating the expected breeding values. RESULTS: Our results showed that buffalo cows that calved in winter season recorded the highest and significant total milk yield (TMY) and daily milk yield (DMY) traits and the best reproductive performance was indicated by the lower number of services per conception and the shortest calving interval (CI) period. Moreover, age at first calving and dry period (DP) showed a highly significant effect on the TMY and DMY. A significant effect for the level of milk production on days open (DO) period was recorded in our study. The range of sires EBV was 540 kg, 295.2 days, 113.9 days, 2.8 months, and 71.1 days for TMY, LL, DO, CI, and DP, respectively. CONCLUSION: Buffalo's breeders must consider the season of calving, parity, and DP in management program because they greatly affect the farm productivity and profitability and they must select animals with higher breeding values to be the parent of the next generation.

Five BoLA-DRB3 genotypes detected in Egyptian buffalo infected with Foot and Mouth disease virus serotype O.

Foot and Mouth disease (FMD) is a contagious disease leads to economically loss in livestock production all over the world. This serious disease is caused due to the infection of the animal with a single-stranded RNA virus (FMDV). This study aimed to investigate the genetic polymorphism of BoLA-DRB3 gene in Egyptian buffalo as a candidate genetic marker included in multi-factorial process of FMD resistance/susceptibility. Also this work aimed to genetically characterization and serotyping of circulating FMD virus in Egypt during 2016. For serotyping of FMDV, RT-PCR was used for FMDV-positive samples and the results declared the presence of serotype O in all tested animals. The sequence analysis of FMDV samples revealed five different patterns for the detected serotype O which were submitted to GenBank under the accession Nos.: MG017361-MG017365. The 302-bp amplified fragments from BoLA-DRB3 exon 2 were digested with HaeIII endonuclease and the results showed that the presence of five BoLA-DRB3 genotypes, among them the genotype AA might be associated with FMD-resistance (P < 0.01). On the other hand, genotype AC could be correlated with susceptibility (P < 0.01) to FMD in Egyptian buffaloes where it was absent in resistant group. The five detected genotypes of BoLA-DRB3 exon 2 were submitted to GenBank with the accession Nos.: MF977316-MF977320. In conclusion, our findings suggested that the detection of different BoLA-DRB3 genotypes may be has a promising role for raising the resistance of Egyptian buffalo against FMDV especially serotype O which is prevalent in Egypt with preferring genotype AA.

The effect of stillbirth on reproductive and productive performance of pure Egyptian buffaloes and their crosses with Italian buffaloes.

High rates of stillbirth in buffaloes are not only emotionally and economically undesirable but also contrary to animal welfare practices. Thus, this study was aimed to investigate risk factors for stillbirth and analyze its effects on the productive and reproductive performance of pure Egyptian buffaloes (PE) and their crossing with the Italian buffaloes (F1 crosses 50%PE and 50%Italian buffaloes and Back cross (BC) 75%PE and 25%Italian buffaloes) under subtropical environmental conditions. Records of a total of 8388 (5169PE, 1494F1 and 1725BC) were used in this study with 1965 actual first parity records (489, 621 and 855, respectively). The incidence of stillbirth in the farms was 12.4% and 9.2% for primiparous and multiparous cows, respectively. It did not vary among seasons or due to gestation length, calf sex and conception after first insemination in BC buffaloes. BC buffaloes with stillbirths had shorter gestation length, first service post-partum and longer dry period (300.32, 33.67 and 207.05days, respectively) compared to those live births (311.28, 33.90 and 140.22days, respectively), implying that these animals could better adapt to the tough circumstances following stillbirth as reproductive indices were only slightly affected due to stillbirths. Contrarily, the productivity and reproductive performance of PE buffaloes were markedly decreased after stillbirth. Their milk yield, average daily milk yield and lactation length were decreased by 6.27, 10.29 and 6.36%, respectively after stillbirth, while days open, dry period and first service post-partum were increased after stillbirth by 14.28, 13.54 and 12.78%, respectively. The results from this study suggest that producers should be promoted to increase the BC animals in their farms with the intention of increasing milk production and ensure superior reproduction efficiencies with lower stillbirth incidence.

The impact of crossbreeding Egyptian and Italian buffalo on milk yield and composition under subtropical environmental conditions.

Buffalo are the second most valuable species in the world for milk production and their milk prices have been based on fat and protein composition. The aim of the paper was to compare the milk yield and composition of pure Egyptian buffalo (EB) and their crosses with the Italian buffalo and to investigate the impact of temperature humidity index (THI) on milk yield and composition under subtropical stressful conditions. 516 lactating buffalo were used (152 EB; 176 F1 crosses 50% EB and 50% Italian buffalo and 188 back cross (BC) 75% EB and 25% Italian buffalo). The results revealed that, milk yield (5·79 and 10·32%) and peak yield (6·36 and 7·67%) were significantly higher in F1 and BC than in EB, respectively. BC had 7·74 and 3·67% significantly higher daily yield when compared with EB and F1, respectively. EB were robust in the hot condition as the only reduction was in the peak of milk production from 15·02 in low THI to 13·72 kg in high THI, but fat and total solids%, were increased from 5·61 and 16·31 THI in low to 7·01 and 17·59 in high THI, respectively. BC was similar to some extent to EB as their milk was similar to EB under sever hot climate conditions (2331·92 and 2327·50 kg, respectively). A statistically significant reduction in the average daily milk yields was detected only in F1 from 10·33 to 8·38 kg in low and high THI level, respectively. The current study showed that BC produced a higher milk with higher daily average milk yield and peak yield with some evidence of robust under sever hot condition which were approximately similar to EB. Thus, it is recommended to encourage the producers to increase the number of BC animals in their farm for improving the milk production to fulfil the demand of Egyptian markets.

Effects of a novel SNP of IGF2R gene on growth traits and expression rate of IGF2R and IGF2 genes in gluteus medius muscle of Egyptian buffalo.

Insulin-like growth factor 2 receptor (IGF2R) is responsible for degradation of the muscle development initiator, IGF2, and thus it can be used as a marker for selection strategies in the farm animals. The aim of this study was to search for polymorphisms in three coding loci of IGF2R, and to analyze their effect on the growth traits and on the expression levels of IGF2R and IGF2 genes in the gluteus medius muscle of Egyptian buffaloes. A novel A266C SNP was detected in the coding sequences of the third IGF2R locus (at nucleotide number 51 of exon 23) among Egyptian water buffaloes. This SNP was non-synonymous mutation and led to replacement of Y (tyrosine) amino acid (aa) by D (aspartic acid) aa. Three different single-strand conformation polymorphism patterns were observed in the third IGF2R locus: AA, AC, and CC with frequencies of 0.555, 0.195, and 0.250, respectively. Statistical analysis showed that the homozygous AA genotype significantly associated with the average daily gain than AC and CC genotypes from birth to 9 mo of age. Expression analysis showed that the A266C SNP was correlated with IGF2, but not with IGF2R, mRNA levels in the gluteus medius muscle of Egyptian buffaloes. The highest IGF2 mRNA level was estimated in the muscle of animals with the AA homozygous genotype as compared to the AC heterozygotes and CC homozygotes. We conclude that A266C SNP at nucleotide number 51 of exon 23 of the IGF2R gene is associated with the ADG during the early stages of life (from birth to 9 mo of age) and this effect is accompanied by, and may be caused by, increased expression levels of the IGF2 gene.

Novel polymorphisms of the IGF1R gene and their association with average daily gain in Egyptian buffalo (Bubalus bubalis).

The objective of this study was to detect insulin-like growth factor 1 receptor (IGF1R) polymorphisms, their allele, and genotype frequencies and to determine associations between these polymorphisms and growth traits in Egyptian water buffalo. Three loci of the IGF1R coding region were amplified by RT-PCR and, subsequently, subjected to sequence analysis, followed by single-strand conformation polymorphism to identify different allelic patterns. A total of 11 novel polymorphisms were detected; 6 SNPs among Egyptian water buffaloes and 5 polymorphisms compared with Indian buffalo (Y12700). Three of those polymorphisms; GAG Indel polymorphism, C261G, and G263C SNPs, were nonsynonymous mutations. The GAG Indel polymorphism led to deletion of E (glutamic) amino acid (aa) in the IGF1R of Egyptian water buffaloes compared with Indian buffalo. However, C261G SNP, which replaced A (alanine) by G (glycine) aa, and G263C SNP, which changed A (alanine) to P (proline) aa, were detected among Egyptian water buffaloes. Three different single-strand conformation polymorphism patterns were observed in exon 21: CC/CC, GG/GG, and CG/GC with frequencies of 0.291, 0.253, and 0.556, respectively. The heterozygous animals (CG/GC) had a higher ADG than homozygous animals (CC/CC and GG/GG) from birth to 6 mo of age. We conclude that the heterozygous haplotype, C261G/G263C, in exon 21 of the IGF1R gene is associated with the ADG during the early stages of life (from birth to 6 mo of age) and could be used as a genetic marker for selection of growth traits in Egyptian buffalo.