Reproduction characteristics of North Moroccan indigenous goats

Evaluation of male reproductive hormones of Kalahari Red and Kalawad goat bucks as affected by age and season under tropical conditions

Comprehensive understanding of reproductive hormones and environmental cues with their relationship is essential for efficient production in livestock sectors involving either assisted or natural reproductive methods. This study evaluated the effects of age and seasonal-associated changes in the blood concentrations of testosterone and follicle stimulating hormone (FSH) of male Kalahari Red (KR) and Kalawad (KW)-crossbred goats. Based on a 2 × 3 × 4 factorial arrangement, a total of 42 bucks (KR n = 21 and KW n = 21) were allotted into three age groups (> 1 ≤ 2 years, > 2 ≤ 3 years and > 3 ≤ 4 years) with seven KR bucks and seven KW bucks each per age group; reared under different seasons (early rainy, late rainy, early dry and late dry). The animals were managed semi-intensively, kept in an open-ventilated pen and subjected to same nutritional regime throughout the one-year experimental period. Follicle stimulating hormone and testosterone concentrations were analyzed in serum samples. Data obtained reproductive hormones were subjected to three-way Analysis of Variance using SAS 1999. Results show that breed had a significant effect (p < 0.05) on both serum FSH and testosterone concentrations. The highest FSH (0.49 ± 0.02 ng/mL, 0.45 ± 0.01 ng/mL, 0.41 ± 0.1 ng/mL and 0.47 ± 0.07 ng/mL) mean values (P > 0.05) were observed in KR in September, October, November and May, respectively while the highest (2.6 ± 0.02 ng/mL) testosterone concentration in KW (p < 0.05) was obtained in December. Testosterone had irregular patterns between breeds and months of sampling. FSH was at peak (p > 0.05) in KR during the late rainy season at all ages while the values of FSH concentration in KW were not significantly different at all ages and seasons. The highest (2.05 ± 0.11 ng/mL) serum testosterone mean value in KW peaked (p < 0.05) age > 3 ≤ 4 years during the late rainy season. Testosterone concentration was lower and steady at all ages during rainy seasons in KR but started fluctuating during the early dry season. The least mean (0.62 ± 0.07 ng/mL and 0.68 ± 0.05 ng/mL) were recorded (p > 0.05) in KW during the late dry season at age > 2 ≤ 3 and > 3 ≤ 4 years respectively. In KR and KW goat breeds raised under tropical condition, the high seasonal variations were responsible for the fluctuations in the reproductive hormones which resultantly altered or lowered the sexual activity of the animals at certain season(s).

Seasonal changes in testis size, testosterone levels and sperm production quality in meat rams

The aim of the present study was to evaluate seasonal changes in testes size, serum testosterone (T) levels and sperm production characteristics of 24 adult (2-3 years old) rams of meat breeds: Charollais (n = 6), Ile de France (n = 6), Dorset (Polled) (n = 5) and Dorper (Dorper, n = 7). Semen was collected with artificial vagina using a female in spontaneous oestrus (September-November, breeding season, BS) or a female with induced oestrus (March-July, non-breeding season, NBS). A total of 672 ejaculates were examined. Jugular vein blood was collected to determine testosterone levels during BS and NBS, and serum was extracted. Results of the present study indicate that there was no significant change in parameters such as body weight (kg) and testes length, both right and left, during BS and NBS, irrespective of the breed. The remaining metrics of testes differ in varying degrees between breeds of rams (with the exception of the Dorper breed) between BS and NBS. No significant variation in these parameters was found in Dorper rams. For all breeds, season had a statistically significant effect on important parameters such as total sperm count and progressive sperm motility after thawing. There was also significant seasonal variation in ejaculate volume across the three breeds, excluding il-de-France rams. The most constant was the sperm concentration, which was unchanged in BS and NBS in the three breeds, excluding Dorset rams, which showed a slightly significant decrease in this indicator in the non-breeding season. The serum content of the major male hormone testosterone (T) in rams of all breeds showed significant changes between BS and NBS, decreasing by a highly significant amount in the non-breeding season.

Influence of Season and Liquid Storage at 16 °C on Beni Arouss Bucks' Semen Quality

Simple Summary

Goat production plays an important economic and social role in Northern Moroccan farming. Beni Arouss is an autochthonous North Moroccan goat breed. The use of artificial insemination can largely contribute to optimised preservation and dissemination of valuable traits of this breed and lead to improved productivity. During liquid storage, the stability of semen good quality remains crucial in order to provide greater flexibility between the artificial insemination center and farms where the insemination of does needs to be performed. The study aims to assess the effect of storage and season of the year on fresh semen of Beni Arouss goats. Every month, ejaculates were collected from bucks and were extended and stored at 16 °C for 24 h. Semen motility, viability and normal morphology were assessed at 0, 4, 8 and 24 h after collection. As expected, these parameters showed a significant reduction within 24 h of storage and during all seasons. However, semen collected in summer maintained a better quality after 24 h of storage at 16 °C than semen collected during the other periods. Therefore, the storage ability of Beni Arouss bucks’ semen stored at 16 °C was higher during the summer.

Abstract

The study aimed at determining the effect of storage and season on fresh semen of Beni Arouss goats. Ejaculates were collected at monthly intervals from seven mature bucks and were extended at a final concentration of 800 × 10⁶ spermatozoa. ml^-1 and stored at 16 °C for 24 h. Semen motility, viability and normal morphology were assessed at 0, 4, 8 and 24 h after collection. Motility and normal morphology parameters were recorded using computer-assisted sperm analysis (CASA) and viability was analyzed using eosin–nigrosin staining. As expected, motility, viability and normal morphology parameters showed a significant reduction within 24 h of storage and during all seasons (p < 0.05). However, semen collected in summer maintained a better quality after 24 h of storage at 16 °C than semen collected during the other periods (p < 0.05). In conclusion, the storage ability of Beni Arouss bucks’ semen stored at 16 °C was significantly higher during the summer.

Evaluation of different hormonal treatments on oestral and ovarian responses in Moroccan Beni Arouss goats during anoestrus and breeding season

The efficacy of eight combinations of fluorogestone acetate (FGA, 20 or 40 mg as intravaginal device during 11 days), equine chorionic gonadotropin (eCG, 300 or 500 UI injected 48 hr before FGA removal) and prostaglandin F_2α (cloprostenol, 0 or 50 μg injected 48 hr before FGA removal) aiming at induction and synchronization of oestrus and ovulation was evaluated during the anoestrus season in spring and during the breeding season in autumn in adult Beni Arouss goats. Oestrous behaviour was recorded between 12 and 60 hr after FGA removal. Blood samplings allowing to assess onset of the pre-ovulatory LH surge and increase of progesterone as sign of an active corpus luteum were performed, respectively, between 20 and 60 hr and 3, 5, 8 and 15 days after FGA removal. No season-related differences (spring vs. autumn) were observed for oestrous response (95% vs. 93%), pre-ovulatory LH surge (94% vs. 84%) and luteal response after 3-8 and 11-15 days post-treatment (respectively 92% vs. 66% and 92% vs. 98%). The onset of oestrus (21 [13-53] vs. 32 [12-54] hr) and LH surge (26 [20-60] vs. 38 [22-60] hr) occurred significantly later in autumn. FGA (40 vs. 20 mg) in autumn significantly delayed the onset of oestrus (36 [16-54] vs. 23 [12-47] hr) and LH surge (44 [26-58] vs. 33 [22-60] hr). Significant treatment-related differences were recorded for onset of LH surge (earliest for 20 mg FGA, 300 IU eCG, 50 μg PGF_2α ) and onset of luteal phase (latest for 40 mg FGA, 300 IU eCG, 50 μg PGF_2α ). In conclusion, the hormone combinations tested appeared equally effective in terms of oestrous and ovulation rates. Season has influenced significantly the onset of oestrus and LH surge, and the high dose regimen of FGA delayed the ovarian response in autumn.

Use Of Hormonal and Ultrasonographic Examinations to Determine the Fetal Number in Bulgarian Local Goats

The purpose of the present study was to determine the fetal number in goats by using hormonal and ultrasonographic examinations. The experiments were conducted with 106 clinically healthy Bulgarian local goats, 1.5 to 7 years of age, weighing 35-52 kg. Hormonal examinations were performed on 24 goats. Serum progesterone concentrations were measured during a 7 days interval, between 21-63 day of pregnancy, and during a 14 days interval until the 133rd day of pregnancy. Ultrasound examinations were performed on 82 goats with a multi-frequency linear transducer (5.0-12.0 MHz). All animals were studied once during an interval of 7 days transrectally (21-28 day, 29-35 day, 36-42 day) and transabdominally (43-49 day, 50-56 day, 57-63 day), respectively. The accuracy of determining the number of singleton and multiple pregnancies by hormonal analysis were 51%, 58%, 69% and 47%, 52%, 62%, respectively. The accuracy of ultrasonography to determine the number of fetuses is highest in singletons 76.18%, followed by twins 72.56% and the lowest in triplets and more fetuses 21.43%. Highest accuracy, sensitivity and positive predictive diagnosis were established in the period 43-49 day of pregnancy (P<0.05). The obtained results show that the most appropriate period is between 42 and 49 day of pregnancy for determination of the fetal number in Bulgarian local goats using ultrasonography.

Effect of season on sexual behavior, testicular measurements and seminal characteristics in "Beni arouss" North Moroccan bucks

Changes in anatomical, behavioural and seminal characteristics were measured throughout the year in seven Beni Arouss bucks maintained at a latitude of 35 °N. Testicular size varied significantly. There were the greatest values during the summer and autumn for scrotal circumference and least in the winter for testicular length. Values for most variables related to sexual behavior were not affected by season except the number of mounts before first ejaculation which was least in the summer. No differences were detected between seasons in terms of semen volume. The sperm concentration, viability and percentage of normal sperm, however, were less during the winter period. The size of sperm heads was larger in the autumn and motility of spermatozoa was greater in the summer and autumn. Results from the correlation analysis indicated that the majority of conventional seminal characteristics were correlated with testis measurements (P <  0.05; r < 0.5). Values for conventional and CASA motility variables indicated there were positive correlations between viability and progressive motility (r = 0.4; P <  0.05) and between the percentage of normal sperm and straight line and average path velocity (r = 0.4; P <  0.05). A global reproduction performance score was established for each buck, which allowed for assessment of magnitude of seasonal changes for each individual. These global score values indicated there was a greater reproductive performance for all bucks during summer and autumn. This study described for the first time seasonal variations of reproductive characteristics of Beni Arouss bucks and results indicate that even though there is a maximal capacity for reproductive performance during the summer and autumn, breeding should be possible throughout the year.

Characterizing neutral genomic diversity and selection signatures in indigenous populations of Moroccan goats (Capra hircus) using WGS data

Since the time of their domestication, goats (Capra hircus) have evolved in a large variety of locally adapted populations in response to different human and environmental pressures. In the present era, many indigenous populations are threatened with extinction due to their substitution by cosmopolitan breeds, while they might represent highly valuable genomic resources. It is thus crucial to characterize the neutral and adaptive genetic diversity of indigenous populations. A fine characterization of whole genome variation in farm animals is now possible by using new sequencing technologies. We sequenced the complete genome at 12× coverage of 44 goats geographically representative of the three phenotypically distinct indigenous populations in Morocco. The study of mitochondrial genomes showed a high diversity exclusively restricted to the haplogroup A. The 44 nuclear genomes showed a very high diversity (24 million variants) associated with low linkage disequilibrium. The overall genetic diversity was weakly structured according to geography and phenotypes. When looking for signals of positive selection in each population we identified many candidate genes, several of which gave insights into the metabolic pathways or biological processes involved in the adaptation to local conditions (e.g., panting in warm/desert conditions). This study highlights the interest of WGS data to characterize livestock genomic diversity. It illustrates the valuable genetic richness present in indigenous populations that have to be sustainably managed and may represent valuable genetic resources for the long-term preservation of the species.