In vitro embryo production (IVEP) is a procedure that can promote genetic improvement in a short time frame. However, the success rates obtained with this biotechnology in water buffaloes are still inconsistent, and can be associated with the high concentration of lipids in the cytoplasm of oocytes and embryos. The objective of this study was to evaluate the effects of reduced concentration of fetal bovine serum (FBS) and/or use of l-carnitine during in vitro maturation (IVM) on the preimplantation development and lipid accumulation in bubaline embryos. In a first experiment, the lowest concentration of FBS in the IVM medium (0%, 2.5%, 5% or 10%) was determined, and the lowest concentration that maintained good embryo development rates was 5%. In a second experiment, the addition of 5 mM of l-carnitine into the maturation medium was evaluated. The blastocysts produced were submitted to lipid evaluation involving staining followed by observation using optical (Oil Red O) and confocal (BODIPY 493/503) microscopy. No difference was observed between the 5% and 10% FBS groups, which were superior to the 0% and 2.5% groups. Furthermore, the performance of the groups treated with 5% and 10% FBS was better than the groups supplemented with l-carnitine. There was no difference regarding embryo lipid accumulation. The results indicated that it is possible to reduce the FBS concentration to 5% in in vitro maturation medium for production of bubaline embryos, and supplementation with 5 mM l-carnitine does not increase embryo production.

Serum protein distribution and concentration can be affected by different physiological and pathological conditions. The aim of this study was to evaluate the changes in the concentration of serum protein fractions and haptoglobin in clinically healthy dairy buffaloes during late pregnancy and early lactation. Blood and milk samples were collected from 30 buffaloes at around 7 d before expected calving (blood only) and 7, 30 and 50 d after calving. In serum samples, the total protein, haptoglobin, albumin, α1-, α2-, β1-, β2-, γ-globulins, and albumin/globulin ratio (A/G) values were evaluated. In milk, fat%, protein%, lactose%, somatic cell score (SCS) were assessed, along with milk yield (MY) and daily milk production (DMP). The peripartum period significantly influenced (P < 0.005) total protein, albumin, haptoglobin, α2-, β2- and γ-globulins (P < 0.005). Milk yield, DMP and fat% changed significantly throughout the monitoring period (P < 0.005). Milk yield and DMP were positively correlated with total protein, albumin, β2-globulins and A/G ratio, and negatively correlated with haptoglobin and α2-globulins. These results provide new knowledge about the serum protein electrophoretic pattern in Italian Mediterranean Buffaloes during the last phase of pregnancy and early stages of lactation.

The aim of this research communication was to identify chromosome regions and genes that could be related to milk yield (MY), milk fat (%F) and protein percentage (%P) in Brazilian buffalo cows using information from genotyped and non-genotyped animals. We used the 90 K Axiom® Buffalo Genotyping array. A repeatability model was used. An iterative process was performed to calculate the weights of markers as a function of the squared effects of Single Nucleotide Polymorphism (SNP) and allele frequencies. The 10 SNPs with the largest effects for MY, %F and %P were studied and they explained 7·48, 9·94 and 6·56% of the genetic variance, respectively. These regions harbor genes with biological functions that could be related to the traits analyzed. The identification of such regions and genes will contribute to a better understanding of their influence on milk production and milk quality traits of buffaloes.

The objective of this study was to apply factor analysis to describe lactation curves in dairy buffaloes in order to estimate the phenotypic and genetic association between common latent factors and cumulative milk yield. A total of 31 257 monthly test-day milk yield records from buffaloes belonging to herds located in the state of São Paulo were used to estimate two common latent factors, which were then analysed in a multi-trait animal model for estimating genetic parameters. Estimates of (co)variance components for the two common latent factors and cumulated 270-d milk yield were obtained by Bayesian inference using a multiple trait animal model. Contemporary group, number of milkings per day (two levels) and age of buffalo cow at calving (linear and quadratic) as covariate were included in the model as fixed effects. The additive genetic, permanent environmental and residual effects were included as random effects. The first common latent factor (F1) was associated with persistency of lactation and the second common latent factor (F2) with the level of production in early lactation. Heritability estimates for F1 and F2 were 0·12 and 0·07, respectively. Genetic correlation estimates between F1 and F2 with cumulative milk yield were positive and moderate (0·63 and 0·52). Multivariate statistics employing factor analysis allowed the extraction of two variables (latent factors) that described the shape of the lactation curve. It is expected that the response to selection to increase lactation persistency is higher than the response obtained from selecting animals to increase lactation peak. Selection for higher total milk yield would result in a favourable correlated response to increase the level of production in early lactation and the lactation persistency.

The present study was conducted to assess the interrelation between teat anatomy and machine milking in dairy buffaloes raised in Switzerland. A 3-min pre-stimulation induced milk ejection before cluster attachment in most cases and caused an optimal milk removal during machine milking. In an additional experiment, longitudinal cross-section ultrasound was obtained before and after a 3-min pre-stimulation. Teat wall thickness, teat diameter, cisternal diameter and teat canal length were evaluated. It was observed that 3-min pre-stimulation dramatically reduced teat canal length whereas all the other anatomical parameters remained unchanged. The vacuum needed to open the teat canal was also measured before and after a 3-min pre-stimulation by using a special teat cup with only the mouthpiece of the liner remaining on the top of the teat cup (no liner, no pulsation). Without pre-stimulation but after wetting the teat canal by stripping one squirt of milk out of the teat, no milk could be withdrawn with a vacuum up to 39 kPa. However, after pre-stimulation, milk flow occurred in all buffaloes at a vacuum between 16 and 38 kPa. In the last experiment, the teat tissue was examined in slaughtered buffaloes and compared with teat tissue of cows. No difference was noted in histological sections and teat canal length was similar in cows and buffaloes. Proximal to the teat canal, the teat did not pass into an open cistern but the lumen was collapsed. In conclusion, buffaloes need to be well pre-stimulated because the tissue above the teat canal provides additional teat closure before milk ejection. Therefore, milk can only be obtained after pre-stimulation.

In the present study, the rôle of gammaglutamyltransferase (GGT) during lactation has been investigated in the water buffalo. GGT activity has been evaluated in the mammary tissue at 4 and 6 months after calving and during the non-lactating period. The highest GGT activity levels were found at day 120 (32·57±7·41 U per g) of lactation and were statistically higher than those at 180 (10·76±3·6 U per g) or during the non-lactating period (9·86±7·94 U per g). Histochemistry confirmed these findings and revealed that GGT reactivity was distributed throughout the cytoplasm of alveolar epithelial cells. Such results showed that the GGT production is high during lactation thus supporting the hypothesis that this enzyme plays a rôle in determining milk production in water buffalo by supporting milk protein synthesis.

In experiment 1, three male calves of Vietnamese cattle and three maleVietnamese swamp buffalo calves were weaned after receiving colostrum and reared by bottle feeding of milk. During the 1st month the animal did not have access to solid food. Urine was collected to determine differences in endogenous excretion of purine between the two types of animal. After that they were given access to equal amount of solid food for 2 months to stimulate rumen development, urine was again collected to determine the differences in purine excretion. In experiment 2, the same animals were given milk mixed with purines in three treatments (0, 1·7 and 3·4 g/day). The same animals were used in experiment 3 for intravenous allantoin infusion, to test the effect of purines themselves introduced into the plasma.The results showed that in period 1 of experiment 1 there was no significant difference in purine excretion between the two types of animal. The excretion being 0·65 mmol/kg M 0·75 for cattle and 0·69 mmol/kg M 0·75for buffaloes calves, respectively. For period 2, after rumen development there were significant differences between two types of animal. The excretion from buffaloes (0·26 mmol/kg M0·75) being less than half that of cattle (0·69 mmol/kg M 0·75).In experiment 2 the regression of purine excretion mmol/day (y) was y=0·6279x+9·1496 for cattle calves and y=0·2618x+5·8594 for buffalo calves where x was the purine given.In experiment 3, from each mmol of allantoin infusion, the recovery was about 0·70 in cattle but only half (0·32) in buffaloes ( P<0·01).It is clearly shown that the difference in purine derivative excretion occur only after rumen development It is suggested that glomerular filtration rate may be lower in buffaloes than cattle leaving more time in the blood thus more time for recycling to the rumen and metabolized by bacteria or the permeability from the blood to the rumen is greater in buffaloes than cattle.

Milking-related release of oxytocin, prolactin, and cortisol was studied following three pre-milking treatments. Six Murrah buffaloes were treated with direct application of milking cluster (O), a 1-min pre-stimulation (M), and combined feeding and pre-stimulation (MF). Machine milk yield, stripping yield and milk composition were recorded. Milk ejection occurred significantly earlier with MF than M and O (P<0·05; 2·50, 5·10 and 6·33 min, respectively). In all treatments, milk ejection occurred with small increases >3–5 ng/l in oxytocin concentration. Increase in oxytocin concentration over a threshold level and milk ejection occurred simultaneously and were closely correlated (r=0·83, P<0·05). There was a positive correlation between total time oxytocin concentration remained elevated over threshold levels and machine yield (r=0·86, P<0·05). For treatment O, milk ejection was inhibited during machine milking, while a marked increase in oxytocin occurred during hand stripping (6 and 16 ng/l, respectively). For treatment M, mean oxytocin concentrations remained unchanged during pre-stimulation but increased during subsequent machine milking and hand stripping (6·38, 18·06 and 12·36 ng/l, respectively). For treatment MF, although there was a 3·6-fold increase during pre-stimulation, oxytocin increased by 10-fold and 3-fold during machine milking and hand stripping, and was significant for machine milking (P<0·05, 17·32, 47·86, 18·13 ng/l, respectively). Milk-ejection-related cortisol release was visible only in treatment MF. For treatments O and M, prolactin concentration increased prior to the increase in oxytocin. The stripping yield was higher, and fat content in the stripping yield significantly lower, for treatment O indicating incomplete milking. Thus buffaloes are easily disturbed even by small changes in milking routines.

Twenty-eight buffalo cows were used to evaluate the effect of housing system on a range of behavioural and physiological variables. Fourteen cows were group-housed in a loose open-sided barn with a concrete floor and 10 m2 per head as space allowance (group IS). Fourteen others were group-housed in a similar barn but they could also benefit from an outdoor yard with 500 m2 per head as space allowance, free access to potholes for wallowing and spontaneous vegetation (group TS). Animals were subjected to six sessions of instantaneous scan sampling at 10-day intervals. Behavioural variables were expressed as proportions of subjects observed in each category of posture and activity. Phytohaemagglutinin (PHA) was used to perform a skin test based on non-specific delayed type hypersensitivity, whereas 20 mg of ovalbumin were injected subcutaneously to evaluate humoral immune response. Blood samples for evaluation of cortisol concentration were collected immediately prior to exogenous porcine ACTH injection and 1, 2 and 4 h after. The metabolic status of the animals and milk production were also monitored. The proportion of idling animals was higher in group IS than in group TS (P < 0.001). More IS buffalo cows were observed eating at the manger than TS animals (P < 0.001). A higher proportion of TS animals were observed in the sun (P < 0.001). Grazing and bathing activities were recorded only for TS animals. Our findings suggest that buffalo cows kept in intensive conditions and having no access to ample yards and potholes may extend their periods of idling with negative effects on the state of welfare. Immune responses, metabolite concentrations and milk production were not affected by treatment, whereas cortisol levels were higher in IS animals (P < 0.05). The provision of a housing system similar to natural conditions was able to improve the welfare of buffalo cows as indicated by the expression of some species-specific natural behaviours. Such conditions were also associated with lower adrenal cortex response to ACTH injection, possibly as a consequence of the higher degree of initiative allowed to TS cows.

Ruminal bacterial counts and in vivo digestibility were determined on four Mediterranean buffalo bulls and four Friesian bulls, all fistulated at the rumen, and given at maintenance level (50 g/kg M0·75 per day of dry matter) four different diets with the same crude protein content (N ✕ 6·25 = 140 g/kg dry matter) and with forage: concentrate ratios as follows: diet D12·5 = 0·875: 0·125; diet D25·0 = 0·75: 0·25; diet D37·5 = 0·625: 0·375; diet D50·0 = 0·5: 0·5. All the animals received the diets during four consecutive periods in a Latin-square design. Buffaloes had higher total microbial counts (10·78 v. 10·08 log10 cells per g dry rumen content, P < 0·01) as compared with cattle; differences in total ruminal bacterial counts among the diets were only observed within the buffalo species (diet D12·5 v. diets D25·0, D37·5, D50·0: 10·04 v. 10·92, 10·98, 11·17 log10 cells per g dry rumen content, P 0·01) and when comparing the two species for each diet, significantly higher values for bacterial counts in buffaloes were found for diets D25·0: 10·92 v. 10·28 (P 0·05), D37·5: 10·98 v. 10·08 (P 0·01) and D50·0: 11·17 v. 9·76 (P 0·01) log10 cells per g dry rumen content. Cattle showed significantly higher digestibility values for: organic matter (0·696 v. 0·676, P 0·05), neutral-detergent fibre (NDF; 0·548 v. 0·511, P 0·05) and cellulose (0·621 v. 0 · 509, P 0·01), while the crude protein digestibility (CPD) values were similar (0·667 and 0·671). Comparing the two species for each diet, cattle showed significantly higher digestibility values for organic matter in diet D50·0 only (0·714 v. 0·688, P 0·01), for NDF in diet D12·5 only (0·578 v. 0·531, P 0·05) and for cellulose in all diets (0·660 v. 0·546, 0·630 v. 0·525, 0·605 v. 0·505, 0·588 v. 0·460, P 0·01); in contrast buffaloes showed higher values of the CPD for diet D12·5 (0·662 v. 0·632, P 0·05).

Estimates of genetic parameters were obtained for weight, hip height, heart girth and shoulder to pin length measurements on Thai swamp buffalo, recorded at birth and weaning. Direct heritability estimates were 0·26 for weights at both ages and were low for skeletal measurements, ranging from 0·11 to 0·19. Low values could, in part at least, be caused by inaccuracies in recording. All traits were subject to maternal effects, permanent environmental maternal effects on traits recorded at weaning explaining proportionately up to 0·14 of the total variation. Estimates of genetic (direct and maternal) and permanent environmental correlations between traits recorded at the same time were high throughout, ranging from 0·83 to 0·97 for additive genetic effects and being close to unity otherwise. Except for heart girth measured at weaning, there appeared to be comparatively little genetic association between traits recorded at different times, direct additive correlation estimates ranging from 0·18 to 0·55 in contrast to estimates of 0·38 to 0·65 for correlations with heart girth at weaning.

Polymerase chain reaction (PCR) primers specific to exon 2 of the bovine lymphocyte antigen (BoLA)-DRB3 gene were used successfully to amplify the equivalent region in 34 Murrah and 36 Surti buffaloes selected at random. The 304 bp amplified product of the DRB3 gene was separately digested with BstγI, HaeIII and Rsal enzymes. Digestion with BstγI enzyme did not reveal any polymorphism and all animals showed a single restriction pattern, which corresponded exactly to the BstγI pattern ‘b’ previously described for cattle. Digestion with HaeIII enzyme resulted in five patterns, four of which corresponded to the Haelll patterns previously reported in cattle. The new HaeIII pattern was observed in both the breeds of buffaloes studied. The fragment analysis with RsaI revealed 13 different patterns. All of these RsaI patterns corresponded to the RsaI patterns previously described for cattle. The high degree of similarity in the restriction fragment length polymorphism (RFLP) patterns of cattle and buffalo observed in the present study provide evidence for the strong conservation amongst other bovine species, of restriction sites previously reported in cattle.

Thirty-two post-partum Mediterranean river buffalo cows were continuously observed for signs of oestrus from September to December with the aid of two vasectomized bulls. Symptoms of oestrus among female Mediterranean buffaloes are weak, therefore oestrus was assessed based on bull behaviour (following and licking a cow and trying to mount her). Oestrus was divided into three phases based on the bull behaviour assessment. Status of the uterus and ovarian follicles were checked rectally every day for each cow which was detected by a teaser bull to be in oestrus. All cows in oestrus were bred twice by artificial insemination (AI), the first at ovulation and the second (using a different bull) 22 h later.

The average duration of interest shown by the bull towards a cow (from the very first to the last sign of interest) was 68 h and the average length of the three phases was: phase 1 = 21 (s.d. 29) h, phase II = 32 (s.d. 24) h and phase III = 15 (s.d. 15) h. Fifteen buffaloes were bled during oestrus, and LH profiles were determined. No differences were evident among oestruses followed by pregnancy (no. = 18) and the others (no. = 26) for the variables describing behavioural events. Neither intensity of the bull courtship, presence or clarity of mucous discharge, or housing system affected the success of AI. The only differences between pregnant and non-pregnant cows were in the timing between the LH peak and the end of phase II (2·4 v. 14·7 h, P < 0·001), end of phase III (22 v. 40 h, P > 0·05) and ovulation (25 v. 46 h, P < 0·05). Successful pregnancies occurred 34 (s.d. 14) h after the end of phase II. The endocrinology and behavioural patterns of buffalo reproduction need further research to clarify the reasons for non-optimal pregnancy rates after AI.

Five mathematical models were compared to select the most satisfactory model to describe digesta kinetics of solids and fluids in the gastrointestinal tract of buffaloes (Mediterranean bulls), cattle (Friesian bulls) and sheep (Delle Langhe rams) given food at maintenance level, according to a Latin-square arrangement for four consecutive periods of 21 days. Chromium mordanted alfalfa hay and cobalt-ethylenediamine tetraacetic acid were used as nonabsorbable markers and were administered through the rumen cannula in a single dose. Four different isonitrogenous diets (N × 6·25 = 140 g/kg dry matter) with different concentrate:forage ratios (12·5:87·5, 25:75, 37·5:62·5, 50:50) were used.

Faecal chromium and cobalt concentration curves were fitted with five non-linear models: three gamma (G2, G3, G4) age-dependent one-compartment, one gamma age-dependent/age-independent two-compartment (G2G1) and one multicompartment (MC).

Wilcoxon tests on residual sums of squares of the different models for solids showed that MC and G4 gave a better fit than G2G1, G2, G3 for all the data and within the species. The comparison of MC v. G4 did not show any significant difference (P > 0·05) for all the data computed together or within each species. Nevertheless, MC had a higher number of curves with lower residual sums of squares in comparison with G4 and was also able to produce estimates of digesta kinetics in the second compartment.

The cobalt excretion curves for fluids, considering all the data, and only within sheep, showed G4 as the best fitting model. When G4 was compared with other models no significant differences were recorded either for cattle: G4 v. G2 (F = 0·6645), G4 v. G2G1 (P = 0·0620) and for buffalo: G4 v. G2 (P = 0·1575), G4 v.G3(P = 0·0796) and G4 v. G2G1 (P = 0·1641).

It is concluded that the multicompartment model (MC) and G4 model were the best fits for solids and for fluids respectively.

The effect of inclusion of live yeast culture (YC, Saccharomyces cerevisiae plus growth medium) in a high concentrate diet given to buffalo (Bubalus bubalis) calves on the rumen microbial population and fermentation pattern and in sacco dry matter disappearance of dietary constituents was examined. Six rumen-fistulated buffalo calves of about 120 kg live iveight were divided into two equal groups. The control group was given a diet consisting of, on a dry-matter basis, 0·90 kg ivheat straw, 1 kg berseem (Trifolium alexandrinum) and ISO kg concentrate per day per calf and the yeast group the above diet plus 5 g YC which was put directly into the rumen via the fistula. After feeding this diet for 6 weeks (supplementation period), inclusion of YC was stopped and both groups were given the control diet for a period of 3 weeks to examine the performance of the YC group after withdrawal of YC. At week 4 of YC supplementation the pH was significantly increased (P < 0·01) and lactate concentration was decreased (P < 0·01) in the rumen fluid for up to 6 h post feeding. The number of total bacteria, total viable bacteria, cellulolytic bacteria, amylolytic bacteria and protozoa were increased proportionately by 0·554 (P < 002), 0·482 (P<0·01), 0·670 (P <0·01), 0·077 (P > 0·05) and 0·079 (P>0·05), respectively. The concentrations of total volatile fatty acids, particularly at 4 h post feeding (P < 0·01), acetate fP < 0·01) and propionate and the acetate to propionate ratio were higher in the YC compared with the control group. On YC inclusion, the concentration of ammonia-nitrogen was decreased while that of trichloracetic acid insoluble protein was marginally increased. All these differences in rumen variables started to disappear on YC withdrawal and values returned to control levels by the 3rd week after YC withdrawal. YC supplementation increased the in sacco dry-matter disappearance of various dietary components particularly after 3, 6 and 22 h incubation.

In the first experiment the animals were worked for 5h/day and/or given 17 h access to food. In the second experiment they were worked for 4 h/day and/or given 20 h access to food. When animals were prevented from feeding on barley straw for 7 h/day their dry-matter intake (DMI) was significantly less than when they were given 24 h access to food. When feeding was prevented for only 4 h/day food intake was not significantly different from that with 24-h access.

A study of feeding behaviour (experiment 2) suggested that when most animals were deprived of food for 4 h they maintained similar intakes to those on ad libitum feeding by increasing their rate of eating, rather than by increasing the time they spent eating. Preventing food intake for 4 h/day was associated with little change in time spent ruminating during the day. On all treatments, the buffalo spent significantly less time eating and more time ruminating than the cattle.

Work, during the periods when food was withheld, had little effect on the DMI of either the buffalo or cattle compared with restricted feeding. No rumination occurred during the time that the animals were at work. However on working days, time spent ruminating was similar to that seen on restricted feeding days, but the animals spent more time ruminating later in the day than when they were able to ruminate during the middle of the day.

Effect of live yeast culture (Saccharomyces cerevisiae plus growth medium) inclusion in the diet of buffaloes (Bubalus bubalis) on milk yield and its composition was examined. Twenty buffaloes (Murrah breed) having an average daily milk yield of 8 to 10 I and in their early lactation stage were divided into two equal groups. The control group was given a basal production diet consisting of 35 to 40 kg green berseem and concentrate mixture (0·5 kg/kg milk produced) per day per animal and the yeast supplemented group the above diet supplemented with 10 g yeast culture (YC, 5 × 109 c.f.u. Saccharomyces cerevisiae strain 1026 per g). The feeding continued for 10 weeks and during this period milk samples collected at weekly intervals and milk yield recorded daily. During this period, average daily milk yield was increased by proportionately 0·135 and fat-corrected milk yield by 0·185 by inclusion of YC. Fat, protein, lactose and total solids in milk increased proportionately by 0·039, 0·051, 0·030 and 0·034 respectively. The corresponding proportional increases in the quantity of these constituents secreted in milk (kg/day) were 0·237, 0·200, 0·200 and 0·204.

Twenty Friesian (group 1) and 20 buffalo (group 2) calves and 14 of each of lactating Friesians (group 3) and lactating buffaloes (group 4) were maintained in middle of winter conditions of Egypt for 2 months. The calves (groups 1 and 2) were of similar age (6 to 7 months) and average body weight (120 kg). The lactating animals were in the fifth season of lactation, non-pregnant, in mid lactation and yielded 12 to 14 kg milk on average daily. Similar groups of animals of the same types (groups 5, 6, 7 and 8, respectively), numbers, live body weights and physiological status were maintained under hot summer conditions for 2 months. The effect of hyperthermia during summer season on Friesians and buffaloes compared with winter was also studied.

The results showed that buffaloes were more tolerant than Friesians to the environmental conditions of Egypt. In winter, buffalo calves had poorer (P < 0·05) food efficiencies (kg gain per MJ net energy), higher dry matter intakes (DMI, P < 0·05) and total lipids in the plasma (P < 0·01) than Friesians, while the contrary occurred in total proteins, albumin, phospholipids and cholesterol (P < 0·05). In summer, growth rate and the concentrations of total lipids, phospholipids and cholesterol in the plasma were higher (P < 0·01), and total proteins and albumin were lower (P< 0·01) in buffalo than in Friesian calves. In summer, in Friesians, both DMI and growth rate decreased (P < 0·05) and food efficiency as kg weight gain per MJ net energy was poorer (P < 0·05). In the plasma total proteins and albumin increased (P < 0·01) but haematocrit %, phospholipids and cholesterol decreased (P < 0·05). In buffalo calves, only total proteins and albumin increased (P < 0·01) due to heat stress.

In lactating buffaloes, food efficiency was poorer (P < 0·01) and DMI and plasma haematocrit % were significantly higher, while the concentrations of total proteins, globulin, phospholipids and cholesterol in the plasma, and milk yield were significantly lower than in lactating Friesians in the winter season. Lactating buffaloes were poorer (P < 0·01) in food efficiency and had lower concentrations of total proteins, globulin and cholesterol than lactating Friesians in the summer (P < 0·01).

An analysis of cow reproductive traits was carried out on 2057 lactation records of Egyptian buffaloes. A total of 651 daughters (paternal half-sisters) of 82 sires were available for the analysis. Reproductive traits analysed were age at first, second and third calving (AC), number of services per conception (NSC), gestation length (GL) and calving interval (CI). Year of calving affected most reproductive traits (P < 0·001) while no important differences were detected among months of calving. Means of NSC, GL and CI decreased linearly (P < 0·01) as parity advanced. Age of cow at calving exerted a pronounced effect (P < 0·001) on NSC and CI. There was no systematic change in the estimates of heritability and sire components of variance for reproductive measures over the first three lactations. Heritability estimates for NSC and GL in the different parities were generally low, ranging between 0·04 and 0·18, while moderate estimates for AC and CI were obtained. Phenotypic correlations between reproductive traits were positive and relatively moderate or low. For most traits, positive and relatively high or moderate estimates of genetic correlations were observed. Mating bull was found to be an important source of variation for reproductive performance of Egyptian buffaloes. The highly significant effect of mating bull on reproductive traits could be considered as evidence for the importance of evaluating bull semen quality before the mating of cows