Effect of exogenous PGF2-Alpha and /or GnRH on libido and semen production of aged friesian bulls

The present study was conducted on six apparently healthy bulls [8-10 years old] used in natural mating. Animals were divided into three groups, each two bulls. Semen was collected and evaluated once weekly, in first and second ejaculates, with three days apart. The present results showed a significant improvement in libido, ejaculate volume, sperm number and fructose content of semen when bulls were treated either with PGF2-alpha or GnRH particularly after the second dose. The combined administration, PGF2-alpha and GnRH exhibited the best improvement for all criteria. From the present study, administration of PGF2 and /or GnRH can be recommended to improve and prolong the reproductive life of an aged bull

Effect of L-tyrosine administration on some trace elements in ram serum and seminal plasma

Out of 30 rams, 12-20 months of age, 14 rams were treated with L- tyrosine, in a single dose of 100 mg/kg body weight and 16 rams were left as control. Three semen and blood samples were collected from each ram once weekly and the seminal plasma and serum were taken for estimating the copper, zinc and manganese content. The present results revealed higher values for these elements in the seminal plasma and serum of the treated group when compared with those in the control. With the exception of manganese, copper and zinc appeared significantly higher in the seminal plasma than those in the serum. The ejaculate volume showed significant correlation which was positive with copper [0.601] and zinc [0.544] and negative with manganese [-0.495]. There was a highly significant positive correlation between the sperm motility and zinc [0.668]

Interaction of season and nutrition on the sexual activity of buffalo bulls

Twelve sexually mature buffalo bulls kept under three systems of feeding for a full calendar year were used in the study. Libido as expressed in term of reaction time was lower in bulls kept on the available [148.55 +/- 17.50 sec.] than the constant [73.48 +/- 6.26 sec.] or the proposed [82.17 +/- 7.65 sec.] feeding systems. It was higher during autumn [67.76 +/- 0.6 sec.] than spring [165.12 +/- 22.50 sec.], winter [87.76 +/- 8.30 sec.] or summer [85.25 +/- 8.70 sec.]. Failure of ejaculation was lower in bulls kept on the available feeding [16.67%] when compared to those on the constant [31.25%] or the proposed [28.13%] systems of feeding. A highly significant [p0.01] interaction was observed between season and nutrition on the sexual desire in buffalo bulls

Interaction of season and nutrition on buffalo semen-I physical characteristics

Twelve sexually mature buffalo bulls were used in the current work. Bulls were assigned into three comparable groups. Each was maintained on a particular system of feeding as follows: [A] constant plane of nutrition; [B] proposed system of grazing and [C] available system of feeding. Following a period of adjustment [7-8 weeks] semen was collected twice weekly during the last five weeks of each sesson. Data concerning all physical characteristics of semen were subjected to statistical analysis. Significant differences [p<0.05] were observed between the different systems of feeding in relation to the ejaculate volume [2.2 +/- 0.1, 1.9 +/- 0.1 and 1.9 +/- 0.1 respectively], sperm output per ejaculate [1885.3 +/- 62.0, 1654.7 +/- 52.1 and 1566.4 +/- 65.3 x 10[6] sperm respectively], sperm resistance to 1% NaCl [48.1 +/- 0.5, 43.2 +/- 0.4 and 45.0 +/- 0.6 x 10[3] respectively] and percentage of morphologically abnormal spermatozoa. All semen characteristics except the initial motility and initial PH showed singnificant differences [p<0.05] between the different seasons. General improvement in most of these criteria were observed during the spring. It can be conclude that semen quality seemed to be more influenced by the change in the level of netrition associated with the change in season

Interaction of season and nutrition on buffalo semen II Chemical composition

Semen from twelve sexually mature buffalo bulls kept under three systems of feeding for a full calendar year was used in the study. The superiority of semen produced by the bulls kept on a constant plane of nutrition was reflected on its chemical composition. An increase in the acid phosphatase activity, chloride and inorganic phosphorus and a decrease in calcium content was observed. It was very difficult to correlate changes in the chemical composition of semen to chemical changes of feed type. It was also difficult to incorporate the superiority in the chemical composition of semen with a definite season since the fluctuations of the chemical parameters themselves between seasons were great. It can be concluded that chemical composition of ejaculates can not be used independently for assessing the quality of semen in relation to feeding and season. However, the only element indicative of nutritional and seasonal effect is calcium

Interaction of season and nutrition on buffalo semen III Factors content and fructolysis index

Semen was collected from twelve sexually mature buffalo bulls kept under three systems of feeding for a full calendar year. The fructose concentration [mg/100m semen] and the fructolysis index were estimated during the last week of each season on four semen samples from each bull. The overall mean of fructose concentration was 500.4+10.0 100 ml semen and the fructolysis index was 1.5+0.1 mg/10[9] spermatozoa at 37 C. the fructose content of the whole semen was significantly different among the different groups of feeding and seasons. Highly significant [p<0.01] differences were observed in fructose utilization /-10[9] sperms among the different seasons, while the differences among groups under different systems of feeding were not apparent. Since the interactions of nutrition and season on the fructolysis were not appaeciable the significant differences in the fructolytic activity between the experimental groups can mainly be attributed to the changes in climatic conditions

Interaction of season and nutrition on buffalo semen IV Biometrics of spermatozoa

Semen was collected from twenty sexually mature buffalo bulls kept under three systems of feeding for a full calendar year. A smear stained with eosin-nigrosin was made from each semen sample and a hundred straignt, live and normal spermatozoa were measured. The overall means of middle-piece, flagellum length, head length, maximal breadth, breadth at base, head area head shape, breadth of middle piece, flagellum length and whole length were 7.06 +/- 0.01 micro, 4.44 +/- 0.01 micro, 2.41 +/- 0.01 micro, 24.30 +/- 0.04 micro[2], 1.60 +/- 0.01 micro, 0.83 +/- 0.00 micro, 55.38 +/- 0.04 micro and 62.37 +/- 0.06 micro respectively. The present study showed clearly a definite relationship between season, nutrition and their interactions on the different mensurations. Highly significant differences were observed in the head length and head at base in relation to the sequence of ejaculation. Highly significant differences were observed in all biometrics between bulls