Sexual behavior, semen characteristics and plasma testosterone level of purebred native Egyptian bulls with emphasis on variations due to seasons and months of the year

The present study utilized 6 sexually mature native Egyptian bulls raised in the National Research Center Farm, nearby Cairo. Bulls were used for collection of a single semen ejaculate / week for a period of one year using artificial vagina. Sexual behavior was measured in term of reaction time and number of mounts per ejaculate. Semen samples were immediately examined after collection for physical, microscopical and chemical properties. Jugular blood samples were collected once in the middle of each month from each bull for assaying testosterone value [Radioimmunoassay]. Results obtained from collection of 312 ejaculates revealed that native Egyptian bulls have reaction time of 41.22 sec and number of mounts per ejaculate of 1.31 with the best parameters during autumn and the poorest parameters during winter. Ejaculate volume [ml.], sperm cell concentration [X10[6] /ml] averaged 3.39, 1181.96 and 4051.180 with the highest values during autumn and the lowest values during spring. Mass motility [0-5] averaged 3.66 with the best value during spring and the lowest during winter. Individual motility and alive sperm percentage were 76.11 and 88.0%, respectively with the highest values during autumn and the lowest values during winter. Sperm abnormalities averaged 12.63% with the best percentage during summer and the highest value during winter. Initial seminal fructose and citric acid concentrations averaged 764.32 and 384.34 mg/dl, respectively with the highest concentrations during autumn and the lowest values during winter and summer, respectively. Sodium and potassium ion concentrations were 180.60 and 108.03 Meq/1, respectively with the highest values during autumn and February, and winter and February, while the lowest values were obtained during spring and June, summer and September, respectively. Plasma testosterone value averaged 4.07 ng/ml with the highest value was obtained during autumn and the lowest value during spring. In conclusion, native Egyptian bulls showed sexual behavior, semen characteristics and plasma testosterone values comparable to those parameters of universal breeds, however, highly significant seasonal and monthly variations were evident with the best results obtained during autumn season and during November and December

Effect of ejaculation on plasma testosterone level of purebred native Egyptian bulls with emphasis on correlations with sexual behavior and semen characteristics

This is study was performed on 6 purebred mature native Egyptian bulls raised in the National Research Centre Experimental Farm nearby Cairo. To investigate the effect of ejaculation on plasma testosterone profile, blood samples were collected before [2 and 1 hr], during and after [1/2, 1, 11/2 and 2 hr] semen collection by means of an artificial vagina. Sexual behavior was evaluated in terms of the reaction time and number of mounts / successful ejaculate. Semen samples were examined and results were correlated with testosterone levels. Testosterone levels were assayed using the radioimmunoassay technique and data were statistically analyzed. Plasma testosterone value [ng/ml] averaged 4.07 +/- 0.43 in purebred native Egyptian bulls. Values obviously decreased after [3.64 +/- 0.17] than before [4.58 +/- 0.23] semen collection. Ejaculation induced more variations in testosterone levels during autumn and less variations during spring. Moreover, correlation coefficients between plasma testosterone level and sexual behavior and semen characteristics of native bulls were recorded. In conclusion, purebred native Egyptian bulls have a comparable blood plasma testosterone level to the universal breeds with obvious individual, monthly and seasonal variations

Effect of immunization against oestradiol-17 beta on some biochemical parameters and reproductive performance in barki ewes

The present study was carried out on 14 Barki ewes raised at the National Research Centre Farm. Ewes were either treated with a mixture of saline and Freund's complete adjuvant [FCA, control group, n=6] or oestradiol-17beta-6-BSA conjugated with FCA [immunized group, n=8]. Ewes were mated after the booster injection. Blood samples were collected to determine lipids, proteins and their fractions. The reproductive efficiency of ewes were recorded. Results revealed no significant changes in plasma lipids, proteins and their fractions between control and immunized groups. Twinning rate increased in immunized [75%] than in control [0%] groups. Meanwhile, there were no significant differences in gestation length, pregnancy rate, lambing rate and lamb birth weight between both groups. It is concluded that active immunization of Barki ewes against oestradiol-17beta-6-BSA increased twinning rate [75%]

Effect of active immunization against estradiol-17 beta on plasma antibody titer and steroids levels in Barki Ewes

The present study was carried out on 14 Barki ewes raised at The National Research Centre Experimental Farm. Animals were treated either with a mixture of saline and Freund's complete adjuvant [FCA] and served as control [n=6] or conjugated estradiol-17beta and served as treated group [n=8]. Ewes were mated after the booster immunization. Blood samples were collected during the different reproductive stages to determine plasma anti-estradiol liters [ELISA] as well as progesterone and estradiol-17beta [RIA] levels. Results indicated that immunized ewes were capable of eliciting antibodies specific to the steroid moiety and titer was detected during the different reproductive stages. Moreover, hormone levels during cyclic, pregnancy and perilambing periods revealed similar pattern in both groups but in variable levels and were significantly higher in immunized than the control group it is concluded that barki ewes responded well to immunization against estadiol-17beta by producing considerable amount of antibody titer

Investigations on Kidding in Egyptian Baladi, goats with emphasis on immunogenetic structures and progesterone level

Twenty late pregnant Baladi goats were used to investigate kidding process with emphasis on the immunogenetic structures and progesterone level. Blood samples were collected during the late stage of gestation for serological investigations against brucellosis, salmonellosis and toxoplasmosis as well as for evaluation of progesterone level, blood grouping and electrophoretic analysis of plasma proteins. Genotypes data from four blood protein loci and 22 antigens of 7 blood groups were used to detect the genetic markers associated with normal and difficult births. Results of the current investigation revealed that despite all the experimental Baladi does were free from brucellosis, salmonellosis and toxoplasmosis, 40% of them suffered from dystocia and they have polymorphic structure of all studied loci. The most frequent antigenic factors of eutocic goats were A[3], Y[2], B, T[1], X x[3], Cb, R. on the other hand, these animals were characterized by predominance of Alb[B] and Tf[B] genes. Concerning dystocic goats they revealed high frequencies of S[26], N and L antigens with predominance of homozygotic genotypes Hb[A], Alb[A], Am[A] and Tf[A] Plasma progesterone level, few days before kidding was obviously lower in eutocic [0.38 ng/ml] than dystocic [13.99 ng/ml] does. It could be concluded from this study that kidding process is mainly controlled by B, cb, S[26], antigens and An[A] gene

Effect of chronic low dose exposure to lead on male reproduction in rabbits

The present study aimed to investigate the effect of exposure to a low dose of lead for a long time on male reproductive performance. Therefore, 60 weaned white Newzealand rabbits were reared in automatic battery system, randomly divided into two groups; a control group that received distilled water and a treated group that received 100 micro g lead acetate micro g/ kg body weight orally/day. Libido, semen characteristics and mating performance were investigated in mature rabbits [20[th] - 35 [th] week after starting the experiment]. Blood samples and testes were collected after sacrificing at 4, 8,12,16, 20 and 36 weeks after the start of the experiment. Androstenedione, testosterone and estradiol-17 B levels were assayed [RIA] in blood plasma. Relative weight, total testosterone in homogenate and histopathological changes of the testes were recorded. Also, residual lead in blood and testes was determined. Results showed that plasma total testosterone and androstenedione levels were significantly lower in lead treated [114 and 7.2 ng/dl, respectively] than control [241 and 12.3 ng/dl, respectively] groups. Estradiol-17B level was not significantly different. Total testosterone concentration in testicular homogenate was significantly decreased in lead treated [3.68 +/- 0.68 micro g /100 mg] than that in control [17.47 +/- 3.71 micro g /100 mg] groups. Relative testicular weight, libido, sperm motility, sperm abnormalities, fertility% and average litter size was significantly lower than that of the control group while a significant increase of sperm abnormalities was noticed than that of control. All these results and others proved that even a marginal lead level could provoque reproductive disorders in male rabbits