Mature Rams Research Articles

Reproductive Management of Rams and Ram Lambs during the Pre-Breeding Season in US Sheep Farms.

Simple SummaryPre-breeding management of rams and their ram lambs is critical for viable, sustainable and profitable farms. A further understanding of the management and selection criteria of the males during pre-breeding enables producers to efficiently use animal resources to maximize the reproductive potential of the animals. The reproductive management of mature rams and their lambs is complex, varying across breeds, farms, and regions of the world. It involves different aspects of animal husbandry, such as genetics, health, nutrition, behavior, economy and physiological and anatomical changes during the non-breeding season. Sound flock management must include an integrative and complete management plan for males and females that provides adequate conditions for the sheep to express their genetic potential and production level. This review article examines some of the key aspects to consider when managing mature rams and ram lambs during the pre-breeding season to ensure proper condition of the males for optimal function during the breeding season.In sheep farms, achieving economic and productive efficiency and sustainability goals is directly related with the reproductive management of the animals. Genetically, the male contribution to the offspring is 50%, but in practical terms, there is a greater potential impact of the ram on reproductive results, because one male has the potential to affect a large group of females and therefore greatly affects the entire flock. Unfortunately, the selection of males for breeding in the US sheep industry has been traditionally conducted based on phenotypical traits, without a genetic/reproductive evaluation, and/or health assessment or records. Therefore, it is important to establish integrative management practices to select the rams and ram lambs to be used in the breeding season. Among these practices are genomic testing, a comprehensive breeding soundness evaluation and assessment of health status and records of the males before the breeding season, to detect and correct potential issues.

Morphofunctional changes in the thyroid gland and pituitary tyrotropes in rams of the Russian long-haired breed in different seasons of the year

In mature rams, the signs of high functional activity of the thyroid gland are observed in the autumn period. An increase in the diameter of the thyroid follicles (109.1±0.58 microns) is marked, the height of the epithelium (9.6±0.11 microns) and the area of the thyrocyte nuclei (32.8±0.38 μm2) increase statistically significant (P<0.001). In the pituitary gland of rams in the autumn period, there is an increase in the number of tyrotropes. The cytoplasm of tyrotropes is filled with secretory granules, which reflects the high level of their functional activity.

Variations in haematological and serum biochemical indices among White Fulani bulls, Ouda rams and West African Dwarf bucks

Variations in haematological and serum biochemical indices among White Fulani bulls, Ouda rams and West African Dwarf (WAD) bucks were studied. Ten each of mature bulls, rams and bucks were used for the experiment. Blood was sampled from all the animals and analysed for haematology and serum was separated for serum biochemical analysis. The result showed that species had effect on some haematological and serum biochemical indices of White Fulani bulls, Ouda rams and WAD bucks. Packed cell volume, haemoglobin, white blood cells, red blood cells, monocytes and eosinophils were not significantly different among the species, while platelets, lymphocytes, and neutrophils counts were significantly influenced by specie differences. Platelets was significantly (p<0.05) lower in rams (93.20×103 /µL) than in bulls (136.00×103 /µL) and bucks (141.90×103 /µL). Lymphocytes and neutrophils count was significantly (p<0.05) influenced by species differences. Serum biochemical parameters showed that there was no significant difference in the mean values for albumin, glucose, cholesterol, urea and Aspartate amino transferase, while the values obtained for total protein, creatinine and Alanine amino transferase (ALT) were significantly (p<0.05) different among the animal species. Total protein (7.21±0.52 g/dL) and creatinine (1.21±0.19 mg/dL) were significantly (p<0.05) higher in bucks than other species. The ALT was also higher (p<0.05) in bucks (20.83 iu/L) than in rams (7.59 iu/L) and bulls (6.27 iu/L). This study suggests that the effect of specie of an animal influences blood indices. The values obtained in this study can be used as references for haematological and serum biochemical assessment of indigenous male cattle, sheep and goat in Nigeria.

Effect of breed, chilling duration and processed product on the quality characteristics of mutton

An experiment was conducted to evaluate the effect of breed, chilling duration and processed product on the quality characteristics of mutton. A total of nine (9) mature rams of 12 months of age (25 Kg) managed on the same system were used. The animals were kept for 24 hours where only water was provided to clear the gut content before slaughter. The experiment was carried out in a factorial arrangement (3 x 3 x 3) of a completely randomized design consisting of three breeds of sheep (Balami, Uda and Yankasa), three chilling durations (0, 24 and 48 hours) and three processed products (Balangu, Tsire and Tukunya). The result revealed that there was no significant (P>0.05) effect of breed on proximate composition of fresh mutton. There was significant (P<0.05) effect of processed product on the proximate composition of mutton. Moisture content was higher in Balangu (54.93 %), followed by Tukunya (51.74 %) and lower in Tsire (41.00 %). Crude protein content was higher in Balangu (33.83 %), followed by Tukunya (29.63 %) which was at par wih Tsire (29.51 %). Ash content was higher in Tsire (6.61 %), followed by Balangu (5.71 %) and lower in Tukunya (3.69 %). Significant (P<0.05) chilling duration effect was obtained for bacteria count which was higher at 0 hours (2.25 x 103 cfu/g) chilling, followed by 24 hours (1.86 x 103 cfu/g) chilling. The same trend was observed for coliform count in which higher value was obtained at 0 hours (4.49 x 102 cfu/g) chilling, followed by 24 hours (3.04 x 102 cfu/g) chilling and 48 hours (2.93 x 102 cfu/g) chilling. Sensory properties of mutton from different breed differed significantly (P<0.05) among processed products. The overall accepatability indicates that Tsire (7.60) product was more acceptable, followed by Tukunya (7.20) product while Balangu (6.86) product was less acceptable. The microbial count obtained from the study was within the acceptable range (< 3.5 log HACCP 2002). It can be concluded that processed meat products (Tsire, Balangu and Tukunya) obtained from different breeds of Nigerian sheep (Balami, Uda and Yankasa) were not homogenous in their proximate composition. It is therefore recommended that fresh mutton should be chilled for 24 to 48 hours with little or no bacteria while fresh meat from the three breed of sheep (Balami, Uda and Yankasa) can be chilled for 24 to 48 hours with little or no bacteria and can be processed into different products (Tsire, Balangu and Tukunya).

Effect of Toxoplasma gondii on Ram Sperm Quality After Experimental Infection.

The aim of this study was to investigate the effect of experimental Toxoplasma gondii infection on ram sperm quality. Five months old, pre-pubertal, rams were divided into four groups (n = 8 per group). Group A was the control group; the remaining animals received per os (p.o.) 5000 oocysts per ram. Group B did not receive treatment post-infection (p.i.). Group C received sulphadimidine (intermuscular injection (i.m.) 33 mg/kg for eight days; every 48 h) two months p.i. and Group D received the same drug twice (24 h p.i. and two months later). Blood samples were collected every 15 days to detect serum immunoglobulin G (IgG). Epididymal sperm samples were analyzed for concentration, kinetics, morphology/viability, functional membrane integrity, DNA integrity, and the presence of parasite DNA. Histopathological examination was performed on the testes. The IgG titres in infected groups raised two weeks p.i. and remained high for four months. Higher values were noticed in viability and functional membrane integrity in positive spermatozoa in the control group compared to other groups, level of significance p < 0.05. Abnormal sperm was higher in groups C and D vs. A and C vs. B (p < 0.05). T. gondii DNA was detected in three sperm samples of the infected rams (12.5%). Histopathology revealed similar findings with little variation among all infected groups, characterized mostly by increased interstitial connective tissue, non-purulent inflammation, and presence of seminiferous tubules with spermatogenic cell depletion, which increased gradually from D to C and B groups. In conclusion Toxoplasmosis in pre-pubertal age negatively affected mature ram sperm quality, while sulphadimidine administration failed to alter this.

Effect of Different Dietary Electrolyte Balance Levels on Physiological Responses and Metabolic Rate of Rams Exposed to Heat Stress Conditions

This study was conducted to evaluate the effects of supplementation of different dietary electrolyte balance (DEB, as the equation of Na+K-Cl milliequivalents (meq) /kg of dry matter) levels on physiological responses and metabolic rate of rams exposed to heat stress and to determine which DEB level is the optimum. A total of 20 Farafra mature rams were used in this trail. These animals were divided into Four equal homogenized groups (5 each) as control (received basal diet only and its DEB was 98 meq/kg of feed DM), T1: DEB 200 meq/kg DM, T2: DEB 300 meq/kg DM and T3: DEB 400 meq/kg DM. Different DEB content of the three treatments was achieved by adding sodium bicarbonate by a rate of 0.74%, 1.48% and 2.22% of kg DM in T1, T2 and T3, respectively. Thermal response parameters, blood constituents, and respiratory activities were determined during the experimental period before (11-12 am) solar exposure and after 3 hours of solar exposure (3-4 pm). The results revealed that supplementation of different DEB levels reduced rectal and skin temperatures and respiration rate before and after solar exposure. However, gas volume per minute (GV) and tidal volume (TV) increased significantly in all treated groups. Volume of oxygen consumption (VO2) and metabolic rate tended to increase by treatment. Also, serum DEB level (Na+K-Cl) increased significantly in all treatments. In conclusion, supplementation of different DEB levels had beneficial effects on the thermal responses, respiratory activities and gas exchange parameters of heat exposed rams and the optimum DEB level is 300 meq/kg of DM.

Vasectomy and Photoperiodic Regimen Modify the Protein Profile, Hormonal Content and Antioxidant Enzymes Activity of Ram Seminal Plasma.

This work aimed to determine the contribution of the testis and epididymis and the effect of the photoperiodic regimen on ram seminal plasma (SP). Semen was collected from 15 mature rams located in an equatorial (Colombian Creole and Romney Marsh, eight intact and two vasectomized) or a temperate climate (Rasa Aragonesa, three intact and two vasectomized). SP proteins were analyzed by Bradford, SDS-PAGE and difference gel electrophoresis (DIGE). Melatonin and testosterone concentrations were quantified by ELISA, and activity of glutathione peroxidase (GPx), glutathione reductase (GRD), and catalase by enzymatic assays. Vasectomy increased protein concentration and the intensity of high molecular weight bands (p < 0.001), with no differences between breeds. DIGE revealed the absence of six proteins in vasectomized rams: angiotensin-converting enzyme, lactotransferrin, phosphoglycerate kinase, sorbitol dehydrogenase, epididymal secretory glutathione peroxidase and epididymal secretory protein E1. Vasectomy also decreased melatonin concentrations in seasonal rams, and testosterone in all of them (p < 0.001), but did not affect antioxidant enzyme activity. Equatorial rams showed lower melatonin and testosterone concentration (p < 0.01) and catalase, but higher GPx activity (p < 0.05). In conclusion, vasectomy modifies the protein profile and hormonal content of ram seminal plasma, whereas the exposure to a constant photoperiod affects hormonal concentration and antioxidant enzymes activity.

Immunolocalization of androgen and vitamin D receptors in the epididymis of mature ram (Ovis aries).

This study illustrated the immunohistochemical distribution of androgen and vitamin D receptors of epididymis in 20 sexually mature ram (Rahmani breed) with average age ranged from (2_4) years and average weight ranged from (50_65kg). Androgen receptor was localized in the cytoplasm of both ciliated and non ciliated cells of efferent ductules, besides the principal cells via the entire epididymal duct. The principal cells of both corpus and proximal cauda epididymis showed the highest immunoreactivity to androgen receptors. Furthermore, vitamin D receptor was localized in the cytoplasm of all epithelium of the efferent ductules besides principal cells of all epididymal regions, however the immunoreaction was significantly higher in the efferent ductules, distal caput and distal cauda epididymis. In conclusion, these results suggest that the function of ram epididymis is regulated by both androgen and Vitamin D.

Decreasing glycerol content by co-supplementation of trehalose and taxifolin hydrate in ram semen extender: Microscopic, oxidative stress, and gene expression analyses

This study aimed to evaluate the comparative effects of taxifolin hydrate and trehalose on the quality of frozen-thawed ram spermatozoa for the first time. Ejaculates collected from six mature rams were pooled, and divided to eight equal aliquots to extend them with different concentrations of glycerol (%5 and %3), taxifolin hydrate (10, 100, and 500 μM), and trehalose (60 mM) as eight groups (G5T0, G5T10, G5T100, G5T500, G3T0, G3T10, G3T100, and G3T500). After freeze-thawing process of cryopreservation, microscopic and oxidative stress parameters, and gene expression levels were investigated for understanding of possible impacts of taxifolin hydrate and trehalose. The study showed that G3T10 resulted in the highest post-thawed viability and mitochondrial activity. Moreover, all extenders with taxifolin hydrate reduced DNA fragmentation in comparison to G5T0, but DNA damage was prevented at the highest rate in presence of G5T10. The level of LPO significantly decreased in the groups G5T500 and G3T100, and the expression levels of NQO1, GCLC, and GSTP1 genes significantly increased in the groups G5T100, G5T500, G3T10, and G3T100 compared to the group G5T0. Finally, co-supplementation of tris-based extender having 3% glycerol with 60 mM trehalose and 10 μM taxifolin hydrate in cryopreservation extender may be recommended to improve the quality of post-thawed ram spermatozoa. However, further in vivo and in vitro studies are suggested to evaluate fertility rates of frozen-thawed ram spermatozoa co-supplemented with trehalose and taxifolin hydrate.

Seasonal variation in testicular blood flow dynamics and their relation to systemic and testicular oxidant/antioxidant biomarkers and androgens in rams.

The environmental temperature increased during summer and decreased during winter to the limits that might negatively affect animal and human reproduction. The responses of Egyptian rams to either hot or cold climatic conditions were studied in six mature rams subjected to weekly testicular Doppler ultrasonographic examination, blood sampling, seminal plasma collection and semen evaluation. The maximum environmental temperature and the relative humidity were used to classify the climatic condition according to the heat stress equation of sheep into hot months where temperature-humidity index (THI) was >26 (31.67±0.54), and cold months where THI was <22 (18.39±0.41). Testosterone, estradiol, superoxide dismutase (SOD), glutathione peroxidase (GPX) and lipid peroxide product (malondialdehyde, MDA) were measured in both blood and seminal plasma, while catalase (CAT) and reduced glutathione (GSH) were measured in blood and seminal plasma, respectively. Results revealed that, during the hot months, rams displayed significantly decreased testicular blood flow, increased seminal plasma MDA, decreased seminal plasma (SOD, GPx and GSH) and blood CAT antioxidant enzymes. The present study evidenced two novel findings: (a) the marked decrease in testicular blood flow volume, that is remarkable increase in both resistive index (RI) and pulsatility index (PI) values, during hot months could be negatively affected both seminal plasma enzymatic activities and seminal attributes, and (b) the SOD and GPx activities in seminal plasma of such animals were suitable predictive markers for seminal attribute evaluation.

Effect of environmental heat stress on Kıvırcık ram sperm parameters

The relationship between environmental conditions and reproduction has been in sight of research. Therefore, there has been a growing interest in effect of climate change, global warming and subsequently environmental heat stress on gametes in last decades. Thus, the present study was designed to investigate the effect of environmental heat stress on Kıvırcık ram sperm parameters. In this study, semen samples (n=72) were collected from six mature rams during a 12-month study period. The temperature and relative humidity of animal box were controlled daily. The mean monthly temperature humidity index (THI) values were calculated to determine heat stress and control periods. According to the mean monthly THI values, the 36 of 72 ejaculates, which were collected between May and October, were classified as heat stress period samples. The others (n=36), which were collected between November and April, were considered as control period samples. The heat stress period sperm samples had lower sperm concentration, motility, viability, membrane integrity and higher abnormal sperm rate compared to control period sperm samples (P&lt; 0.05). Semen volume, sperm DNA integrity and the ability of sperm to undergo acrosome reaction were detected similar between the heat stress and control periods. In conclusion, environmental heat stress was found deleterious for some sperm parameters in Kıvırcık rams.

Evaluación de los niveles de cortisol y testosterona durante el proceso de colecta de semen mediante electroeyaculador en carneros con y sin tranquilizante.

Las técnicas más utilizadas para la recolección se semen ya sea con fines de conservación de material génico o reproductivos son: la vagina artificial y el electro eyaculador. Ha existido controversia por el uso del electroeyaculador por la comunidad científica debido al estrés que causa este método y se consideraría atentar al bienestar animal. El objetivo de este estudio fue valorar los niveles de estrés causados por el uso del electro eyaculador en carneros tratados con tranquilizantes y sin tranquilizante. Se midió los niveles de cortisol y testosterona en carneros maduros sexualmente de la raza Corriedale los mismos que estaban en un promedio de 2,5 años ± 0.5 años, con un peso promedio de 75 kg ± 15 kg de los semovientes. El número de colectas que se realizaron a los carneros fueron de 8, administrándose a las 4 primeras colectas Xilacina en concentración al 2% mediante IV a dosis de 0.05 mg/kg, 10 minutos antes de realizar el procedimiento de colecta, las 4 últimas colectas no se realizaron la aplicación tranquilizante. Para la determinación de los niveles hormonales de cortisol y testosterona se produjo a extraer muestras de sangre 20 minutos después del uso del electro eyaculador, los niveles hormonales se midieron mediante la prueba de ELISA. Para el análisis de resultados se tomó como referencia las tablas de Kolmogorov-Smirnov y Shapiro-Wilk para los análisis hormonales con y sin Xilacina, así mismo se utilizó como base las pruebas paramétricas de Mann-Whitney Las pruebas estadísticas no mostraron diferencia significativa en el uso de los 2 tratamientos, dando como resultado niveles similares de cortisol y testosterona en los tratamientos.

Oestrus synchronization efficiency in ewes and ram maturity effect on fertility during summer season

The purpose of this study was to investigate oestrus synchronization efficiency and ram maturity effect on fertility of ewes of MIS sheep population during summer season. Research was performed on the experimental sheep farm of the Institute for Animal Husbandry in Belgrade, Serbia. The study included 70 crossbred ewes of MIS sheep population (Pirot Pramenka, Merinolandschaf and Ile de France breed) and 3 Ile de France rams (2 young, sexually unexperienced rams and 1 mature ram). Oestrus was synchronized in all 70 ewes using progestagen impregnated vaginal sponges (30 mg fluorogestone acetate) in combination with 500 IU PMSG. Ewes were mated with rams 48 h later. Obtained fertility and productivity results were as follows: lambing rate 57.14% (40/70), gestation length 147.11, litter size 1.82, stillborn rate 15.07%, birth weight of lambs 4.29 kg and body weight of lambs at 30 days of age 13.07 kg on average. Based on the results obtained in this study it was concluded that presented oestrus synchronization and mating protocol yielded lower than expected lambing rate. The effect of ram maturity on lambing rate was significant (P&lt;0.05), as ewes mated to mature ram had higher lambing rate compared to those mated to two young unexperienced rams. Mature ram also had bigger litter size and higher stillborn rate, as well as lower birth weight of lambs.

PSX-42 Characterization of the effects of high selenium feed on spermatogenesis in rams

Abstract Selenium (Se) is an essential element that is required by animals to maximize health and production. Some western rangelands contain alkaline soils that are naturally high in Se while others have been contaminated with elevated concentrations of bioavailable Se. Anecdotal evidence of poor reproductive efficiency has been reported on some seleniferous ranges. In order to determine the effects of high Se feeds on spermatogenesis, mature rams were fed alfalfa pellets containing 0.1, 7.5, 15, or 25 ppm Se. Desired Se concentrations were achieved by mixing western aster containing approximately 3,000 ppm Se with alfalfa. Pellets were fed at 3% of body weight for twelve weeks during the breeding season. Semen and blood samples were collected weekly and semen viability, motility, and morphology were evaluated. After twelve weeks of being fed high Se pellets, one testicle from each ram was surgically removed for morphometric and histological evaluation. The rams were then fed a control alfalfa pellet during an eight week recovery period while monitoring and collection of samples continued. At the conclusion of the recovery period the second testicle was surgically removed for analysis. None of the rams demonstrated any visible clinical signs of chronic Se poisoning during the study. Rams fed the high Se-containing alfalfa pellet had a decrease in sperm motility and an increase in the percentage of abnormal sperm. Within several weeks of beginning the recovery period, the negative side effects were reversed. Initial histological surveys suggest minimal histologic changes. This is supported by the rapid recovery of spermatic motility which suggests a maturation defect and not a change in spermatogenesis. These findings indicate that in sheep, subclinical Se intoxication does cause significant male reproductive damage. More work is needed to better characterize this damage and to determine its effect on fertility and production.

Morphological Changes in the Dental Pulp of Experimental Animals in the Treatment of Acute Partial Pulpitis using Modern Materials

Aim.To study the morphological changes in the tooth pulp of experimental animals when modelling acute partial pulpitis using calcium silicate modified with light-cured resin and calcium hydroxide.Materials and methods.An experimental model of acute partial pulpitis was applied including the formation of a cavity on the lingual surface of the tooth, which corresponded to advanced caries in terms of depth, followed by a slight perforation up to the tooth pulp with a sharp probe. This model of acute partial pulpitis was reproduced for 32 teeth in four sexually mature rams. The teeth were extracted together with the surrounding sockets 15, 30 and 90 days after the modelling of pulpitis, followed by their fi xation in 10% solution of neutral formalin. Decalcification was performed in 25% solution of Trilon B. The material was poured into celloidin; histological sections were stained with hematoxylin and eosin according to Masson’s trichrome procedure.Results.The histological examination of pulp from the main group (calcium silicate modified with light-cured resin) revealed the formation of a biological barrier from secondary dentin in the area of the cavity and perforation up to the pulp chamber on the 90th day after the experiment started. The tooth pulp revealed no signs of an inflammatory process. On the 90th day after the experiment started, no pronounced morphological changes in the main substance and dentinal tubules in the area of the cavity walls were noted in the coronal pulp of experimental animals from the comparison group (calcium hydroxide). A focal chronic inflammatory process was noted in the tooth pulp.Conclusion.It was established that the use of calcium silicate modified with light-cured resin in the experimentally created model of acute partial pulpitis was accompanied by the formation of a biological barrier and a well-developed zone of reparative dentin in the area of the cavity and perforation up to the pulp chamber, as compared to the group where calcium hydroxide was used. Thus, the study results confirmed the efficay of using calcium silicate modified with light-cured resin within the biological method for treating acute partial pulpitis, which shortens the functional recovery of tooth pulp.

Effect of feeding hydroponic barley sprouts to sheep on feed intake, nutrient digestibility, nitrogen retention, rumen fermentation and ruminal enzymes activity

This study was conducted to evaluate the effect of feeding hydroponic barley sprouts to sheep on dry matter intake, nutrient digestibility, nitrogen balance, rumen fermentation parameters and ruminal enzymes activity. The barley sprouts were prepared in a hydroponic sprouting unit under controlled environment. Barley grains were first washed, soaked for one day using tap water, and then covered with a wet towel for another one day for germination. Thereafter, they were spread out in trays and were irrigated three times daily by tap water. The trays contained green fodder were removed after 8 days and the harvested carpets were exposed to air ventilation, then weighed and shredded to small pieces before feeding to the animals. Twenty mature rams (50 ± 1.30 kg bw) were randomly distributed into four groups, each with five rams. The rams in group 1 and 2 were fed on Egyptian clover and hydroponic barley sprouts only, respectively, while the animals in group 3 and 4 were offered the same forage sources used in previous groups but with supplying a concentrate mixture. The experiment lasted for three weeks. It was found that feeding of sprouted barley alone reduced total DM intake by about 61.5% than that of the clover alone, but this effect was ameliorated when fed with the concentrate. However, the digestibility of different nutrients was increased in sprouted barley diet by an average of 10.0% compared to the clover. The nitrogen retention % was similar in rams fed barely sprouts or clover without concentrate. Total volatile fatty acids and propionate production was higher by 18.5% and 8.31%, respectively, in rumen of rams fed the sprouts alone or with concentrate than the clover alone. In addition, feeding of barley sprouts increased the total rumen protozoa count by about 31.3% and most of ruminal enzyme activities (45.0, 9.0 and 23.2% for amylase, cellulose and protease, respectively) compared to the clover. Providing the concentrate with sprouted barley or clover improved the nutrients digestibility (by about 14.0%) and nitrogen retention (by 46.0%) as well as amylase (by 60.0%) and urease (by 15.0%) activity in comparison to feeding of these ingredients alone. In conclusion, feeding of barley sprouts alone to sheep reduced the DM intake, however, it can improve the nutrients digestibility, rumen fermentation and ruminal enzyme activities. Moreover, use of sprouted barley in sheep diets could result in better digestibility and fermentation results than the clover. Feeding of concentrate with sprouted barley increased its positive effect on nutrients digestibility and rumen fermentation and improved the total DM intake. Thus, it can be recommended to feed the hydroponic barley sprouts with the concentrate to obtain an optimal DM intake as well as a high animal performance.

Impact of old age and season on Chios ram semen quality

The present study aimed to provide new and objective information regarding the effect of season and age on the characteristics of Chios ram semen. The semen collection was performed biweekly throughout a year, including both breeding and non-breeding periods. Seven active Chios rams were divided in two age groups: three rams of 2–6 years old (mature) and four rams of 9–13 years old (old). After collection, semen volume and sperm concentration were measured. One hundred sixty-eight (168) semen samples were collected, extended and evaluated. All samples were tested for motility and kinetics (Computer Assisted Sperm Analyzer), viability-membrane integrity (Eosin-Nigrosin), morphology (SpermBlue®), chromatin integrity (Acridine Orange Test) and sperm membrane biochemical functionality (Hypo-osmotic swelling test, HOST). Motility did not differ significantly between periods (p > 0.05) or between age groups (p > 0.05). The percentage of hyperactivated spermatozoa and head abnormalities was higher in the non-breeding compared to the breeding period (p = 0.011 and p = 0.001, respectively). Tail abnormalities were higher in the breeding (p = 0.022) and HOST + spermatozoa were lower in the non-breeding period (p < 0.001). Significantly higher values of semen volume (p = 0.001) and concentration (p < 0.001) were noticed in old compared to mature rams. In conclusion, old rams, up to the age of 13 years, preserve high semen quality, while season affects ram sperm membrane biochemical functionality and head morphology.

Studies of Selenium Deficiency in the Wumeng Semi-Fine Wool Sheep.

Wumeng semi-fine wool sheep are affected by a disease, characterized by emaciation, stiffness and trembling of the limbs, weakness and inability to stand, and sudden death. The objective of the study was to determine possible relationships between the disease and mineral deficiencies. Samples of wool, blood, and liver were collected from affected and healthy sheep. Samples of soil and forage were collected from affected and unaffected areas. The samples were used for hematological and biochemical analyses and mineral nutrient measurements. Results showed that selenium concentrations in forage and soil samples from affected areas were significantly lower than those from unaffected areas (P< 0.01). Meanwhile, selenium concentrations of wool, blood, and liver from the affected sheep were also significantly lower than those from the healthy sheep (P< 0.01). The mean concentration of hemoglobin (Hb), packed cell volume (PCV), and mean corpuscular hemoglobin (MCH) from the affected sheep were significantly lower than those from the healthy sheep (P< 0.01). Serum glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) activity in the affected sheep were significantly lower than those in the healthy sheep (P< 0.01). Serum creatine phosphokinase (CPK), lactate dehydrogenase (LDH), glutamate pyruvate transaminase (GPT), glutamic oxaloacetic transaminase (GOT), alkaline phosphatase (ALP), and malondialdehyde (MDA) values in the affected sheep were significantly higher than those in the healthy sheep (P< 0.01). Serum concentrations of free triiodothyronine (FT3) and triiodothyronine (TT3) in the affected sheep were significantly lower than those in the healthy sheep; serum concentrations of free tetraiodothyronine (FT4) and tetraiodothyronine (TT4) in the affected sheep were significantly higher than those in the healthy sheep (P< 0.01). But the administration of selenium and vitamin E by hypodermic injection prevented and cured the disease. The injection contains 0.1% and 5% of sodium selenite and vitamin E, respectively. A single dose is 6, 6, and 2mL for mature ewe, mature ram, and lamb, respectively, repeated only once 15days later. This study demonstrated that the disorder of Wumeng semi-fine wool sheep was mainly caused by the selenium deficiency in soil and forage.

Nutritional influences on reproduction in mature male sheep and goats

Changes in the nutrition of mature rams and goat bucks lead to profound responses in testicular size and therefore the rate of production of spermatozoa. These effects are largely due to changes in the size of the seminiferous tubules and in the efficiency of spermatogenesis. With the exception of severe undernutrition, the effects on spermatogenic function are not accompanied by similar changes in endocrine function of the testes, as measured by the production of testosterone or inhibin. In rams, moderate changes in nutrition affect gonadotrophin secretion for only a few weeks, whereas testicular growth is affected for several months. In mature male goats during the non-breeding season, nutrition-induced testicular growth does not seem to be associated with a gonadotrophin response. Such observations have led us to develop the hypothesis that nutrition-driven testicular growth is at least partly independent of changes in gonadotrophin secretion. The energetic components of the diet, rather than the protein content, seem to be responsible for affecting gonadotrophin secretion in rams. The volatile fatty acids, and not glucose, are the active factors, although intracerebral insulin may also play a role. Where these substrates act and whether they are also involved in the gonadotrophin-independent pathways requires testing. In conclusion, nutritional signals exert powerful effects on the reproductive system of mature male ruminants, and the responses are partly independent of changes in gonadotrophin secretion. In the gonads, the gametogenic tissue responds rapidly to changes in nutrition, but the endocrine compartments are less affected. Variations in the expression of the nutritional responses among sexes, breeds and species probably reflect variations in the role of this environmental factor as a modulator of reproductive function.

Effects of supplementation of Tris-egg yolk extender with royal jelly on chilled and frozen-thawed ram semen characteristics

This study was conducted to examine the effect of supplementation of Tris-egg yolk extender with lyophilized royal jelly (RJ) on chilled and frozen-thawed ram semen parameters. Ejaculates were collected by artificial vagina from 4 mature rams, twice a week for 4 weeks. Only samples with motility of ≥70% were included, pooled and divided into four equal parts and then diluted in extenders with various concentrations of RJ (0, 1, 3 and 5%, vol/vol) to a final concentration of 200 × 106 sperm/mL and was incubated at 37 °C for 30 min and were subsequently evaluated. After equilibration of extended semen for 2 h at 4 °C, some semen samples were packed in 0.25 mL plastic straws. Then, the straws were frozen in the liquid nitrogen vapor phase for 15 min and stored at −196 °C in liquid nitrogen. The frozen straws were thawed in warm water (37 °C) for 30 s and evaluated; whereas, other semen samples were stored in the refrigerator (4 °C) up to 7 days. The chilled samples were kept in water bath (37 °C) for 5 min and then were evaluated. After dilution, the lowest and highest sperm total abnormality was recorded in 3 and 5% RJ supplemented groups, respectively (P < 0.05). The chilled sperm total motility and membrane integrity were significantly (P < 0.05) higher in 3% than those in 0% and 5% RJ supplemented groups. The chilled sperm progressive motility and viability was significantly (P < 0.05) higher in 1 and 3% than those in 0 and 5% RJ supplemented groups. The frozen-thawed sperm total motility, progressive motility, membrane integrity and viability were significantly higher in 3% RJ supplemented group (P < 0.05). In conclusion, supplementation of Tris-egg yolk extender with 3% lyophilized RJ had a protective effect on chilled and cryopreserved ram spermatozoa.