University of Khartoum

Seasonal Influence on Reproductive Traits and Artificial Insemination Results of the Sudan Desert Rams

Seasonal Influence on Reproductive Traits and Artificial Insemination Results of the Sudan Desert Rams

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Title: Seasonal Influence on Reproductive Traits and Artificial Insemination Results of the Sudan Desert Rams
Author: Elsayed, Abdelsattar Ali
Abstract: The present thesis aimed to study the reproductive traits of Hamari rams to characterize Hamari rams reproductive traits in order to be used in the genetic improvement program using AI technique and to modernize the traditionally encamped production system of sheep in the Sudan to meet the local and foreign market demands. The necessary information for achievement of these was collected through 8 experiments which included field survey conducted during summer and winter seasons to investigate external reproductive traits of 200 Hamari rams with ages ranging between less than one year and four years and the extent of application of Kunan as a traditional practice for control of breeding in sheep. To collect information on development of reproductive traits from birth till puberty, effect of season on the physical characteristics of semen, effect of season on short-term storage of semen diluted in homogenized milk at room temperature compared with undiluted semen, effect of degree of scrotal split on some semen characteristics (individual motility, concentration, percentage of live/dead spermatozoa), effect of season on sexual performance as indicated by the reaction time, and monitoring results of oestrous synchronization and AI in Hamari, Watish, and Hamari X Watish ewes during summer and autumn seasons. The field survey 1. The body condition score of Hamari rams ranged between 2.5±0.5 degrees for young rams less than one year old, and 4.07±0.46 degrees for mature rams at 4 years of age. Season was noticed to have an effect on body condition score. The highest body condition score obtained for young rams was in summer and in winter for mature ones. 2. Scrotal circumference ranged between 30.2±1.59 and 31.00±l.66 cm in young rams and 35.7±1.88 - 33.9+1.70 cm for mature rams. Body condition score and season significantly affected scrotal circumference. Scrotal circumference increased with increasing body condition and increased in summer compared to winter season. Correlation between age and testis size was significant. The older Hamari rams had larger testis size than young ones. Scrotal thickness ranged between 2.0±0.34 and 3.01±0.51 degrees for less than one year old and 4 years old rams, respectively. Season affected scrotal thickness and was greater in winter than in summer within the same age. Scrotal thickness increased (P < 0.05) with increasing body condition score. II. The extent of application of Kunan 1. Kunan is used for reproductive control by nomads during the dry period in natural pastures. The overall percentage of Hamari rams controlled by this method reached 87% during summer. Rams with Kunan (from all ages) were greater in number during summer than in winter (67% versus 14%). Most of the rams controlled by Kunan were between the age of 1 and 4 years. The larger percentage (75%) of rams without Kunan was found in rams less than one year of age while the least percentage (0.0%) was found in 4 years old rams. III. Development of reproductive traits of young Hamari rams Thirteen young Hamari rams were used to study development of reproductive traits from birth to the age of 8 months. Young rams were weighed every 15 days till the age of 8 months. The average birth weight was 3.89±0.58kg. The best growth rate of young Hamari rams was obtained during the first and second months and the growth rate was 5.64±0.80 kg and 4.19±1.48 kg/month, respectively. The testes descended in the scrotum at an average age of 83.2±5.5 days. Separation of penis from the prepuce was attained at the age of 156.9±:7.3 days. Puberty in Hamari rams was reached at the age of 5.5±0.21 months, with an average body weight of 23.3±0.25 kg, and scrotal circumference of 25.25±l.76 cm, average ejaculate volume of 0.6±0.14 ml, individual motility of 17.5 ±17.6 and concentration of 20±8.48Xl07 sperm/ml. IV. Seasonal variations in semen characteristics. Eight Hamari rams were used to study physical characteristics of the semen. The semen was collected once weekly for one year using an electro-ejaculator. The parameters studied included ejaculate volume, colour, mass motility, individual motility, concentration, percentage of live/dead, and percentage of morphological abnormalities. The ejaculate volume ranged between 1.01±0.03 and l.14±0.16 ml. The volume started to increase in July, with a peak value at September and then started to decline until December, but these changes were not significant. The average mass motility ranged between 3.8±0.22 and 4.3±0.l4. The highest mass motility was obtained in August. The average individual motility ranged between 73±2.83% and 84.6±0.96%. The lowest individual motility was obtained in May while the highest ones were in August. The averaged sperm concentration ranged between 2.01±9.09 and 2.17±20.78xl09 sperm/ml. Higher sperm concentration was obtained in August compared to other months. The averaged percentage of live/dead sperms ranged between 82.8±2.92% and 90.7±2.21% and the lowest values were recorded during May and the highest values during August. The percentage of normal spermatozoa ranged between 94.7±0.82 and 96.5±0.37% and the upper limits were noticed during July to December and the lower ones during May to June. The predominant types of sperm abnormalities included coiled tails (1.6±0.76%) and loose heads spermatozoa (1.2+0.52%), while the incidences of tails without heads (0.60 ±0.26%) and broken mid-piece (0.50±0.26%) were less frequent. High better values for semen quality was obtained during autumn and comparatively less values were reported in summer and winter. Monthly and seasonal variations were recorded in all semen characteristics, but there was no serious deterioration in sperm production or semen quality rating at any month or season of the year and they were all within the acceptable limits. V. Effect of season on short-term storage of diluted and undiluted semen. Diluted and undiluted semen of Hamari rams was stored at room temperature. There was no significant difference between them in individual motility within the first and second hours of storage. However, there was a progressive reduction in the individual motility with time and was more marked in undiluted semen than in the semen diluted in homogenized milk. In summer, after 6 hours of semen storage, there was a complete cessation of individual motility, and this occurred after 8 hours in autumn and winter. The longest period reported for individual motility in diluted semen was equally obtained in autumn and winter (11 hours), while in summer this period did not exceed 8 hours. Individual motility of diluted and undiluted semen obtained in autumn and winter was comparable, but was significantly lower in undiluted semen in summer compared to the diluted semen. VI. Effect of scrotal split on semen characteristics. Three groups of Hamari rams were studied for the effect of scrotal split on semen characteristics. The degrees of split studied were 66%, 33% and 0% (without split). There was a significant variation in individual motility of semen obtained from rams with split and those without split. Rams with scrotal split of 33% showed higher sperm concentration followed by scrotal split of 66% and finally rams without spilt. No significant variation was noticed between the three groups for percentage of normal spermatozoa. VII. Effect of season on sexual performance (reaction time). There was a significant variation in the average reaction time (the time spent by a ram from its introduction to a restrained ewe until it completed its first service) between first mount (42.73±4.47 seconds) and the second mount (74.82±4.47 seconds). In all months, the second mount recorded longer time than the first mount. The variation in reaction time was evident between summer and autumn, summer and winter, but there was no significant variation between autumn and winter. The shortest reaction time for the first mount was recorded in July (28.18±5.36 seconds) while the longest was recorded in May (70.29±8.56 seconds). Some rams failed to exhibit even one mount during the whole months of summer but thereafter, they resumed their normal sexual performance. VIII. Artificial insemination (A.I) field results. Sixty four ewes were used. They were randomly divided into 2 equal groups. In the first group, 18 ewes were synchronized with progesterone impregnated vaginal sponges and were artificially inseminated in summer, while 14 ewes were used as control (natural heat and hand mating). The second group of 20 ewes was synchronized as in the first group and artificially inseminated in autumn. Additional 12 ewes were used as control. Pregnancy diagnosis was carried out depending on non-return rate till 60 days and abdominal palpation from the time of insemination after 90 days post-insemination. Conception rate of ewes artificially inseminated was 83.33% in autumn versus 85.71% for ewes used as control, while in summer the conception rate of ewes artificially inseminated was 70% versus 83.33% for control. Conception rates of ewes naturally or artificially inseminated in autumn and summer was 84.37%, and 75%, respectively. There were no significant variations in conception rates for ewes naturally or artificiality inseminated, but ewes inseminated naturally needed longer periods (41-56 days) to achieve these results. The ultimate goal of this study was to provide essential information on Hamari rams reproduction for formulation of a sound future breeding programme for sheep to assist production improvement in the Sudan, and to encourage investment using modern techniques and new management systems in this field
URI: http://khartoumspace.uofk.edu/handle/123456789/14279
Date: 2015-06-23


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