Does Size Matter? Testicular Volume and Its Predictive Ability of Sperm Production in Rams.

Over the years, testicular volume has been used to evaluate the reproductive capacity of rams and the effects of different factors related to reproductive performance. The aim of this study was to determine the most suitable tool and formula to calculate testicular volume under field conditions to guarantee a more accurate determination of sperm production. First, testicles from 25 rams (n = 50) were measured in vivo and postmortem using calipers and ultrasonography during the breeding season (BS). The accurate testicular volume (ATV) was calculated through water displacement. In addition, the sexual status of donor rams was evaluated during a period of four years in a reproduction center, and the three most crucial groups in terms of genetic value and seminal collections were studied in the second part of this experiment: ER-NBS (Elite rams during the non-breeding season), ER-BS-S (Elite rams with a standard frequency of seminal collection), and ER-BS-O (Elite rams with a high frequency of seminal collection). The total testicular volume (TTV), testosterone (T), and total spermatozoa obtained from two consecutive ejaculates in the same day (SPERM) were measured, and the relationship between SPERM and TTV and T was analyzed to predict SPERM. Although all published formulas revealed statistically significant differences (p ≤ 0.05) from the ATV, our proposed formula (ItraULE) (Testicular volume = L × W × D × 0.61) did not show significant differences. In the second part of the study, in the ER as a model donor ram for its high genetic value and high demand from farmers, TTV and T showed strong positive correlations with SPERM (r = 0.587, p = 0.007 NBS; r = 0.684, p = 0.001 BS-S; r = 0.773, p < 0.0001 BS-O). Moreover, formulas were established to predict SPERM in these practical scenarios. In conclusion, the use of ultrasonography and a new formula adapted to rams could improve the prediction of SPERM considering crucial factors such as season and semen collection frequency.

Lesions of the prepuce and penis in rams: A retrospective study.

In the ovine reproductive management, a thorough breeding soundness evaluation including specific inspection of the male genital tract represents a valuable tool for assessing the reproductive potential of a selected subject and for diagnosing genital disorders. During examination, accurate inspection on penis and prepuce is necessary, since conditions affecting these structures may hamper regular coitus. Records from 1270 males undergoing breeding soundness evaluation (n = 1232) or admitted for genital disorders to the Section of Obstetrics and Gynaecology (n = 38) of the Department of Veterinary Medicine, were collected, and lesions of penis and prepuce were therefore classified. The data collected revealed that 47/1270 rams examined presented lesions of the penis and prepuce. The most frequent condition was urolithiasis accounting for over 2% of the cases, followed by lack of the urethral process (0.39% incidence), lack of the glans penis and hypospadias (0.23% cases). Moreover, most of the conditions (40%) were observed in animals less than 2 years old, suggesting the importance of a careful breeding soundness evaluation in animals at young age.

Satisfactory breeding potential is transiently eliminated in beef bulls with clinical anaplasmosis.

BACKGROUND: Natural service breeding is common in U.S. cow-calf operations. Diseases impacting bull reproductive performance have significant economic consequences for producers. Anaplasmosis may be an underappreciated cause of poor reproductive performance in bulls. The primary systemic effects of bovine anaplasmosis including anemia, fever, and weight loss, can all result in unsatisfactory reproductive performance. The objective of this pilot study was to evaluate breeding soundness examination (BSE) outcomes and clinical changes in bulls during and upon resolution of clinical anaplasmosis. Anaplasma marginale-challenged bulls were observed for clinical disease and infection progression and changes in breeding soundness compared to uninfected control bulls for 16 weeks. RESULTS: All Anaplasma marginale-challenged bulls were PCR-positive, seropositive, and showed clinical signs by 3-, 17-, and 24-days post-challenge, respectively. Clinical signs of anaplasmosis included pallor, icterus, fever (≥ 40.2 °C), and weight loss. Acute anemia was observed in all challenged bulls with PCV nadirs ≤ 18% and peak percent parasitized erythrocyte ≥ 50%. Decreased scrotal circumference and poor semen quality (e.g., increased percentage of abnormal spermatozoa, decreased progressively motile sperm), were initially observed within days after onset of clinical anaplasmosis signs and continued weeks beyond disease resolution. Control bulls remained negative for A. marginale. CONCLUSION: This pilot study demonstrates that clinical anaplasmosis reduces breeding soundness in beef bulls. Anaplasmosis should be considered as a differential for bulls with decreased semen quality, especially within endemic areas. A 90 day or greater retest window is recommended for bulls of unsatisfactory breeding potential recently recovered from clinical anaplasmosis.

Breeding soundness examination (BSE): a decision-making tool that requires a particular guideline for male goats.

Breeding soundness examination (BSE) is a common evaluation to predict the reproductive ability of male livestock. The generated guideline for BSE is specified for each animal species to enhance the performance of BSE. However, there is no particular BSE guideline for bucks yet; then, the BSE guidelines for ram and bull are commonly used for bucks. This investigation was conducted to determine the main BSE characteristics and the appropriate age range for assessment in Boer goats. For this purpose, semen was collected using electro-ejaculation, and seminogram variables (semen-BSE traits) were evaluated using conventional methods. The association between common testicular biometric variables (TBVs) and semen-BSE traits were assessed using Pearson's correlation coefficients and multiple linear regression. Logistic regression was used to test the validity of TBVs for the BSE of Boer goats. In this study, a strange appearance of the head of sperm, known as "rod-in-head" (RIH), was observed. The results showed that the appropriate age range for performing BSE in bucks is 12-30 months. Moreover, scrotal length in the range of 10-15.9 cm was the eligible TBV to be used as a predictor for semen-BSE traits. It was suggested that developing a BSE guideline for bucks is necessary for unbiased selection in performing BSE.

Effects from aging on semen quality of fresh and cryopreserved semen in Labrador Retrievers.

Characteristics of frozen sperm associated with fertility and aging have not been fully determined in dogs. The aim of this study was to determine the relationship between fresh and post-thaw sperm quality, age, among the factors of motility, viability, morphology and oxidative stress in a group of fertile stud dogs with extensive breeding records and in dogs with reported subfertility problems. Sperm parameters from 39 fertile dogs were measured in fresh semen and frozen thawed semen. Additionally, frozen semen from 9 subfertile dogs was thawed and analyzed. Subfertile dogs were defined by referring veterinarians solely on the basis of owner history; breeding records were not available to this study. Evaluation included total motility (TM) and progressive motility (PM), average path velocity (VAP), viability, morphology and presence of sperm reactive oxygen species (ROS). Fertile males' ages ranged from 1 to 10 years, subfertile males' ages ranged from 4 to 14 years. All dogs were assigned to age groups according to age as young (1-3 years) middle (4-6 years) and senior (>7 years). The effect of sperm state (fresh vs. frozen-thawed), age, and fertility history (fertile vs. subfertile) on the measured endpoints were determined using a mixed effects model. TM showed a negative correlation with age in the frozen-thawed semen. Additionally, TM in fresh semen was higher in all age groups compared to post thaw semen (P < 0.05). PM was higher in all age dogs of fresh semen compared to frozen-thawed semen (P < 0.05). As such, TM and PM in post thaw semen statistically decreased compared to fresh semen regardless of age of stud male (P < 0.05). Differences in VAP were only observed between young and senior age groups in fresh semen (P < 0.05) while young and middle age dogs from fresh semen were different in all age groups for frozen-thawed semen (P < 0.05). ROS was higher in the young frozen-thawed semen compared to the young fresh semen (P < 0.05). When comparing TM, PM and VAP of fertile vs. subfertile dogs, middle aged fertile dogs are different from middle aged and senior subfertile dogs (P < 0.05). No differences were found in measures of ROS between fertile and subfertile. For sperm viability and morphology, differences were observed between all age groups of fertile dogs in comparison to all ages of subfertile dogs (P < 0.05). Sperm motility appeared to be the most affected parameter by freezing damage than any other parameter measured in this study, while we were not able to determine a significant association between ROS production and fertility status.

Equine sperm-bound antisperm antibodies are associated with poor semen quality.

Antisperm antibodies (ASAs) have been associated with infertility in stallions. The objectives of this study were to investigate the frequency of ASA-positive semen samples in satisfactory and non-satisfactory breeder stallions, the association between ASA binding and semen quality, and factors that may affect the diagnosis. Breeding soundness examinations were performed in 21 stallions and the percentage of IgG- and IgA-bound spermatozoa was evaluated using flow cytometry. Median IgG and IgA binding did not differ between the first and second ejaculates. The percentage of IgA-bound spermatozoa was higher in non-satisfactory (n = 10) than satisfactory breeder stallions (n = 11). However, IgG binding or frequency of IgG-positive ejaculates did not differ with stallion classification. The IgG-positive stallions had significantly lower total sperm motility, concentration and total numbers than IgG-negative stallions in the first ejaculate, and lower sperm concentration in the second ejaculate. The IgA-positive stallions had lower total sperm motility, normal spermatozoa and total numbers than IgA-negative stallions in the first ejaculate, and lower total sperm motility, normal spermatozoa and total numbers in the second ejaculate. While IgG binding did not differ with season, IgA binding was higher in the non-breeding season (n = 6 stallions) than the breeding season (n = 15 stallions) in the first ejaculate. Stallion age did not differ with ASA classification. In conclusion, IgG binding was highly prevalent in both groups of stallions, while IgA binding was higher and more prevalent in non-satisfactory breeders. Both isotypes were associated with poor semen quality. Season and sexual rest had an effect on IgA but not IgG binding.

Ultrassonografia no auxílio do diagnóstico de vesiculite seminal em touros de corte / Ultrasonography in the diagnosis of seminal vesiculites in beef bulls

A vesiculite é um processo inflamatório das glândulas vesiculares, podendo ser unilateral ou bilateral, que acomete reprodutores. O objetivo do presente trabalho foi avaliar a utilização da ultrassonografia como meio de diagnóstico precoce das alterações das vesículas seminais em touros. O presente trabalho foi realizado no município de Videira, Santa Catarina. Analisou-se um total 42 reprodutores, com média de idade de 15 meses, das raças Aberdeen Angus e Polled Hereford em semi-confinamento. Foi realizado exame clinico do estado geral dos animais e exame andrológico dos reprodutores. As amostras de sêmen para a realização do exame das características físicas do ejaculado foram obtidas por eletroejaculação. Através da palpação retal, realizou-se a avaliação das glândulas vesiculares por ultrassonografia. A análise estatística dos dados foi realizada por meio de análise de variância (ANOVA) para comparação entre médias com nível de significância de 5%. A presença de vesiculite foi observada em 31 animais (73,8%) dos 42 analisados. Dos 31 animais portadores 11 animais (35,5%) apresentaram vesiculite bilateral e 20 apresentaram vesiculite unilateral (64,5%; P<0,05). Animais com perímetro escrotal maior tendem a desenvolver vesiculite unilateral, tal fato pode ser explicado pela precocidade sexual agravado pela sodomia entre os animais. O uso do ultrassom auxilia de forma preventiva a detecção de animais portadores de vesiculite em reprodutores.(AU)

The vesiculite is an inflammatory process of the vesicular glands, unilateral or bilateral, that affects bulls. The purpose of this study was to evaluate the use of ultrasound as a complementary method for early detection of changes in seminal vesicles in bulls. This study was conducted in the municipality of Videira, Santa Catarina. We evaluated 42 bulls, with an average age of 15 months, Aberdeen Angus and Polled Hereford breeds and in semi-confinement. Clinical animal examination and andrological exam were performed in all animals. Semen samples were obtained by electroejaculation and physical characteristics of the ejaculate were performed. Rectal palpation was performed by ultrasonography to evaluate vesicular glands changes. Statistical analysis of the data was performed using analysis of variance (ANOVA) for comparison between means with significance level of 5%. The presence of vesiculitis was observed in 31 (73.8%) from the 42 analyzed bulls. Of the 31 animals, 11 animals (35.5%) presented bilateral vesiculitis and 20 showed unilateral vesiculitis (64.5%; P<0.05). Animals with a larger scrotal perimeter tend to develop unilateral vesiculitis, which can be explained by the sexual precocity observed by sodomy among animals. In this way, the use of ultrasound helps preventively to detect animals with vesiculitis in breeding animals.(AU)

Testicular volumetry and prediction of daily sperm output in stallions by orchidometry and two- and three-dimensional sonography.

Accurate determination of the testes volume and prediction of the daily sperm output (DSO) is valuable information for reproductive management of a stallion. The aim of this study was to compare different methods for measuring the testes volume, including caliper, 2D and 3D ultrasound. Special emphasis was on feasibility of 3D volume analysis. First, 22 castrated testes were measured and derived volumes were compared with volumes determined via volume displacement in a graded cylinder with saline solution. Then, during the breeding season, testes sizes of 52 stallions were measured in vivo and analyzed. With the derived volumes, predicted DSO (pDSO) values were calculated which were compared with actual values (aDSO) determined from semen evaluation. Analyses of castrated testes revealed a discrepancy between volume assessments via the caliper and ultrasound methods and actual volumes as found via volume displacement. The smallest difference was found for 3D volume analysis, followed by caliper and 2D ultrasound. Testicular volumes of breeding stallions were highest if determined via 3D ultrasound, followed by measurements using 2D ultrasound and caliper. Correlation between the total testicular volume (TTV) and aDSO was high with volume assessment via ultrasound (2D: r = 0.639, p < 0.001, and 3D: r = 0.604, p < 0.001), and moderate for using caliper (r = 0.46, p < 0.01). Linear regression analyses of TTV and aDSO values revealed that changes in aDSO in part could be explained by differences in testes volume: 32% and 27% in case of 3D and 2D ultrasound, and 12% with caliper. pDSO values that were predicted from testicular measurements correlated best with aDSO values from semen collection protocols in case of using 3D ultrasound (r = 0.56, p < 0.001), followed by 2D ultrasound (r = 0.52; p < 0.001) and caliper (r = 0.34, p = 0.01). In conclusion, 3D ultrasound can be performed on equine testes for more accurate volume predictions, which in turn may increase precision when determining the breeding potential of a stallion.

Yearling Bull Breeding Soundness Examination: Special Considerations.

Accurate assessment of yearling bulls is important for the bottom line of all interested parties: the buyer, the seller, and the veterinarian performing the BSE. Special considerations and current research are highlighted and their application to the evaluation of yearling bulls is discussed.

Reproductive Systems for North American Beef Cattle Herds.

A systems approach to beef cattle reproduction facilitates evaluating the flow of cattle through the herd population based on temporal changes in reproductive and production state. The previous years' timing of calving has either a positive or negative effect on the present year's reproductive success. In order to create and maintain high reproductive success, one must focus on: developing heifers to become pregnant early in the breeding season, ensuring bull breeding soundness, aligning the calving period with optimal resource availability, managing forage and supplementation to ensure good cow body condition going into calving, and minimizing reproductive losses due to disease.

Evaluating Information Obtained from Diagnosis of Pregnancy Status of Beef Herds.

Good reproductive efficiency is critical for economic sustainability of beef herds. Standard measurements of reproductive success are the percentage of cows exposed to bulls at the start of the breeding season that are pregnant at midgestation and the percentage of pregnant cows that give birth to a live calf. Converting fetal age data to a reproductive profile displaying pregnancy percentages by 21-day periods provides information for the diagnosis of suboptimal reproductive efficiency and guides intervention strategies. The value can be amplified by evaluating reproductive profiles by animal age or management group.

Bulls grazing Kentucky 31 tall fescue exhibit impaired growth, semen quality, and decreased semen freezing potential.

Serum prolactin (PRL) and testosterone concentrations, body weight, body composition, semen quality, and semen freezing potential for bulls grazing the toxic tall fescue (Lolium arundinaceum [Schreb.] Darbysh. = Schedonorous arundinaceum [Schreb.] Dumort.) cultivar Kentucky 31 (E+) compared with a novel endophyte cultivar lacking ergot alkaloids (E-) were evaluated. Angus bulls were allotted to treatment (Day 0) and grazed E+ or E- for 155 days. Treatment-by-day interaction was significant (P < 0.05) for serum PRL concentrations with E+treated bulls exhibiting reduced PRL values compared with E- control bulls, but no differences were observed for serum testosterone concentrations (P > 0.05). Further, bulls on the E+ treatment exhibited decreased total gain, average daily gain, and body weight by Day 140 (P < 0.05) compared with the E- bulls. Rump muscle depth was lower because the treatment in bulls grazing E+ compared with E- (P < 0.05) and intramuscular fat in the E- bulls compared with the E+ group was higher by Day 155 (P < 0.05). Analysis of ejaculates showed significant treatment × day effects for sperm concentration with lower values observed for bulls on the E+ treatment (P < 0.05). The percent normal morphology was reduced in ejaculates from E+ bulls compared with E- bulls (P < 0.05), and the difference was due to an increase in abnormal sperm present in the E+ ejaculates from Day 84 to 140 (P < 0.05). In addition, spermatozoa motility and progressive motility were decreased on thawing in semen samples from E+ bulls compared with E- bulls (P < 0.05).

Exposure of prepubertal beef bulls to cycling females does not enhance sexual development.

The objective of this study was to determine whether continuous, long-term, fenceline exposure of prepubertal beef bulls to cycling beef females reduced age at puberty and influenced the percentage of bulls that passed an initial breeding soundness examination (BSE). Bulls (Angus, n = 37; Simmental, n = 22; Hereford, n = 10; Simmental × Angus, n = 8) at an average age of 202 ± 21.5 days were given either continuous fenceline and visual exposure to cycling females (exposed, n = 41) or no exposure (control, n = 36). Estrus was induced in cycling beef females so at least three females were in standing estrus each week during the 182 days of exposure to bulls. Scrotal circumference (SC), body weight, and blood samples were collected every 28 days. When bulls had SC of 26 cm or more, semen samples were obtained monthly via electroejaculation until puberty was achieved (≥50 × 10(6) sperm/mL with at least 10% progressive motility). Behavioral observations were conducted twice monthly: once when females were in estrus and once during diestrus. Homosexual mounting, flehmen responses, and number of times near penned females were recorded for each observation period. Breeding soundness examinations were conducted when the average age of bulls was 364 ± 21.5 days. Normal sperm morphology of at least 70% and sperm motility of at least 30% were required to pass the BSE. Age, body weight, and SC at puberty did not differ between exposed and control bulls (320 ± 28 and 311 ± 29 days; 466.2 ± 12.2 and 437.7 ± 13.5 kg; and 34.4 ± 2.5 and 34.9 ± 2.5 cm, respectively). Percentage of bulls passing their initial BSE did not differ between treatments (exposed, 87.8%; control, 75.0%). Treatment, month, and female estrous stage interacted (P = 0.05) to affect the number of mount attempts and flehmen responses. Exposed bulls entered the cow area more times (P < 0.001) during estrus than diestrus in Months 1, 2, and 3. We concluded that bulls given continuous, long-term, fenceline exposure to cycling beef females do not have enhanced sexual development.