Evaluation of sexual behavior of hair sheep rams in a tropical environment

Testicular Ultrasound Analysis as a Predictive Tool of Ram Sperm Quality

Simple Summary

In animal production, the prediction of male fertility is vital for the success of specific techniques such as artificial insemination. Thus, testicular ultrasound, a non-invasive diagnostic procedure, could be a useful tool. Moreover, recent ultrasound-video analysis and software developments allow the visualization of tissue at the microscopic level. The objective of this work was to establish a possible correlation between testicular ultrasonography and semen quality in rams. For this purpose, the testicles of nine rams were evaluated and the semen was analyzed for one year. The results revealed that the number of white and grey pixels correlated with sperm parameters indicating poor seminal quality. On the other hand, the increase in the seminiferous-tubule density or the lumen area of these tubules was related to a rise in seminal quality. Therefore, ultrasound-video analysis could be a good tool for evaluating the fertility of rams, either for artificial insemination or on the farm.

Abstract

Testicular ultrasound is a non-invasive technique that could be very useful for predicting ram seminal quality. Recent software developments allow macroscopic and microscopic evaluation of testicular parenchyma. Thus, the aim of this study was to evaluate the testicular echotexture using ultrasound-video analysis and investigate its possible correlation with semen quality. Nine rams were evaluated for one year using a portable ultrasound scanner and the echotexture was analyzed with ECOTEXT^® software. The number of black (Ec1), white (Ec2), and grey pixels (Ec3), tubular density (TD), lumen area (LA), and lumen diameter (LD) were analyzed. Semen was collected by an artificial vagina the same day and the sperm concentration, morphology, motility, viability, phosphatidylserine (PS) translocation, reactive-oxygen-species (ROS) levels, DNA damage and capacitation state were evaluated. Ec2 and Ec3 correlated positively with “bad quality” sperm parameters (the percentage of spermatozoa with high ROS levels, with PS translocation and proximal cytoplasmic droplets), and negatively with motility. In contrast, TD and LA showed a positive correlation with “good quality” parameters (motility or normal morphology) and a negative correlation with spermatozoa with high ROS levels, with DNA fragmentation, and proximal or distal cytoplasmic droplets. Thus, echotexture analysis by ultrasound-video analysis could be a valuable tool for assessing ram fertility.

Evaluation of morphological traits and physiological variables of several Chinese goat breeds and their crosses

The current study was undertaken to evaluate some morphological traits of the goat breeds raised in Southwest China. The field experimentation and data collection were from 434 animals presenting seven breeds of the Dazu black goat (DBG; n = 203), Saanen milk goat (SMG; n = 50), Black Boer × Dazu black goat (BXC; n = 28), Hechuan white goat (HWG; n = 49), Inner Mongolia Cashmere goat (IMCG; n = 25), IMCG × DBG (F₁; n = 57) and F₁ × F₁ (F₂; n = 22). All studied animals were adult and selected to be at the same age (36.50 ± 0.75 months). After editing, more than 20 morphological and production traits like body condition score (BCS), testicle measurements, coat colour, fibre traits, skin colour, horn colour, horn shape, horn orientation, wattles, front hair, beard, ear shape, ear size, rump angle, hind leg angulation and physiological variables were analysed. BXC and DBG had dark coat colour, whilst SMG, HWG and IMCG had light colour, whilst F₁ and F₂ ranged from light to dark coat colour. Concerning BCS, the breeds BXC and DBG were characterized as fat goats, whilst SMG, HWG, F₁ and F₂ were average, whilst IMCG was thin. The maximum values for testis measurements were recorded for BXC, SMG and DBG. For fibre traits, IMCG, F₁ and F₂ were the most superior. BXC and DBG males have good fertility parameters. The highest values for rectal temperature, skin temperature and breath rate were recorded for SMG. These findings revealed the presence of a wide range of morphological differences among studied goat breeds. Such diversity in the performance of goat breeds raised in Southwest China is crucial to implement reliable selection strategies for breeding goats in this area.

Polymorphisms of the melatonin receptor 1A (MTNR1A) gene influence the age at first mating in autumn-born ram-lambs and sexual activity of adult rams in spring

The aim of this study was to determine whether polymorphisms of the melatonin receptor 1A (MTNR1A) gene influence the age at first mating in autumn-born ram-lambs and influence the out-of-season sexual activity of adult rams. In experiment 1, 24 Rasa Aragonesa ram-lambs born in September were genotyped for their RsaI and MnlI allelic variants of the MTNR1A gene, and the date of their first mounting with ejaculation after a period of semen collection training was documented. In experiment 2, the reproductive behavior, testicle size, and plasma testosterone concentrations of 18 adult rams (6 rams for each RsaI genotype) were recorded at the beginning (March) and end (May) of the seasonal anestrus. The number of days of training to achieve the first mating with ejaculation in T/T (C/C: 85.17 ± 12.08 C/T: 86.60 ± 18.87; T/T; 26.50 ± 24.50 d; P < 0.05), and G/G ram-lambs (G/G: 51.57 ± 14.99; A/G: 95.58 ± 10.95 d; P < 0.05) was significantly fewer than it was in the other genotypes. Likewise, for the RsaI genotype, 55% of the vulva-sniffing (P < 0.001), 48% of the approaches (P < 0.01), 48% of the mountings (P < 0.05) and 49% total activities (P < 0.001) were performed by T/T rams in March, and 50% of the sexual events in May (P < 0.001). For the Mnll variant, G/G rams performed a significantly (P < 0.001) larger proportion of the vulva-sniffing (41%), approaches (46%) and total activities (40%) in March, and 52% of the vulva-sniffing (P < 0.001), 43%, of the approaches (P < 0.001), 46% of the mountings (P < 0.05), and 47% of the total activities (P < 0.001) in May. Scrotal circumference, testicular volume, and plasma testosterone concentrations did not differ significantly among genotypes. Results confirmed that the polymorphisms of the MTNR1A gene sequence can influence reproductive performance in young and adult rams. Autumn-born ram-lambs that carried the T/T or G/G genotype had an advanced ability to reproduce, and T/T or G/G adult rams exhibited the most intense reproductive behavior. Genotyping might be a useful procedure for identifying the correct and rational use of rams in modern sheep farming.

Dominance rank and the presence of sexually receptive females predict feces-measured body temperature in male chimpanzees

Quantifying the costs of mating is key for understanding life-history trade-offs. As a reflection of metabolic rate, body temperature is one metric for assaying these costs. However, conventional methods for measuring body temperature are invasive and unsuitable for the study of free-living populations of endangered species, including great apes. A promising proxy for body temperature is fecal temperature, the internal temperature of fecal deposits shortly following defecation. We validated this method with humans, finding that maximum fecal temperature is a reliable proxy for rectal temperature. We then applied this method to wild chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda. We collected and analyzed 101 fecal temperature measurements from 43 adult chimpanzees (male: N = 28; female: N = 15). Chimpanzee fecal temperature ranged from 33.4 to 38.9 °C, with a mean of 35.8 °C. Although fecal temperature was not predicted by sex, age, or ambient temperature, male fecal temperature was 1.1 °C higher on days when sexually receptive females were present and was positively correlated with male dominance rank. Post hoc analyses showed that overall copulation rates, but not aggression rates, were positively correlated with fecal temperature, suggesting that sexual physiology and behavior best explain mating-related temperature variation. Together, these results indicate fecal temperature is a reliable proxy for core body temperature in large-bodied mammals, captures metabolic costs associated with male mating behavior, and represents a valuable noninvasive tool for biological field research.

Reproductive behavior in hair sheep rams under tropical conditions

The reproductive efficiency of sheep herds depends to a great extent on the ram. Male reproductive evaluation allows to select for the best and eliminate those with reproductive problems. The objective was to evaluate the effect of breed and age group on the reproductive behavior of hair sheep rams in the tropics of Mexico. Pelibuey (n = 42), Blackbelly (n = 30), Dorper (n = 44), and Katahdin (n = 30) rams of two age groups: young (n = 74, 1-1.5 years old) and adult (n = 72, 2-4 years old) were evaluated. Serving capacity (10-min duration) and breeding soundness evaluation (BSE) tests were carried out in each ram. In the first test, rams were classified as suitable and unsuitable, and in the BSE test, they were classified as satisfactory, questionable, or unsatisfactory. The response variables were analyzed using chi-square test or analyses of variance (ANOVA). ANOVA included the fixed effects of breed, age group, and their interaction. In the serving capacity test, 79.5% of the rams were considered suitable, with no breed differences (P > 0.05). Adult rams (90.3%) had the highest proportion of suitable rams (P < 0.05). In the BSE test, 80.2% of the rams were satisfactory; only breed being significant (P < 0.05). Pelibuey breed had the highest proportion of satisfactory rams (91.4%). Breed × age interaction was no significant for any trait. After serving capacity and BSE tests, a high proportion of rams was found not suitable for reproduction (36.3%), which is expected to cause low fertility in the flock.

Barbados Blackbelly: the Caribbean ovine genetic resource

Ovine production is one of the most important activities in animal production in tropical regions. The Barbados Blackbelly, a very interesting genetic resource, particularly well adapted to a harsh home environment in the humid tropics of the Caribbean. This review concerns this breed. It comprises aspects related to the breed history and standards and most importantly its reproductive and productive performances and gastrointestinal parasite tolerance in the Caribbean, North America and Central America and their introduction and use in crossbred trials in other regions of the tropics.

Developmental changes in testicular interstitium in the Najdi Ram Lambs

This experiment was designed to study the relationship between growth rate and sexual development in Najdi ram lambs. Forty-five Najdi ram lambs were used in nine age groups (1-9th month age), keeping 5 lambs in each group. Results show that mean testis size and scrotal circumference increased at a constant rate, reaching a maximum value of 392.00 ± 2.00 g and 25.00 ± 0.32 cm respectively, at the age of 9 months. A similar trend of growth was observed for the mean body weight, reaching a maximum value of 40.2 ± 0.20 kg at the age of 9 months. There was a positive correlation between the increasing rates of body weight and size of the testis. There were significant differences (P < 0.05) in testis size, scrotal circumference and body weight of lambs between all ages (1-9 months). The histological section of testis showed that a small number of mature sperms appeared in the eighth month of age and their numbers increased in the ninth month. In conclusion, the current findings indicated that puberty in Najdi rams occurs between the 8th and 9th months of age.

Sexual behaviour of yearling Awassi, Charollais x Awassi and Romanov x Awassi rams exposed to oestrous Awassi ewes

This study was conducted to evaluate the sexual performance of 10-month-old, ram lambs of different breed groups. Eight ram lambs each of Awassi (A), F1 CharollaisxAwassi (CA) and F1 RomanovxAwassi (RA) breed types were subjected to sexual performance tests by being individually exposed to two oestrous Awassi ewe lambs for four 20-min periods. Bouts of leg kicking and anogenital sniffing were similar among breed groups. Mounting frequency was greater (p<0.05) in RA than in A and CA ram lambs. Tail-raising was greater (p<0.05) and mating rate tended to be greater (p<0.10) in A than in RA and CA ram lambs. The number of mounts per tail-raising (efficiency) was influenced by breed group and test day (p<0.05). Awassi ram lambs maintained the best efficiency throughout the experiment. Efficiency in RA and CA ram lambs improved with each test day. Results of the present study indicate that RA ram lambs have greater mounting frequency than A and CA, while Awassi are more capable of mating with fat-tailed females than the CA and RA ram lambs.