Indigenous cattle and buffalo bulls’ sexual behaviour and its effects on semen production
Manisha Sethi1
1PhD Scholar (Department of Animal Reproduction, Gynaecology & Obstetrics), ICAR-National Dairy Research Institute, Karnal-132001, Haryana (India)
Abstract
The long-term genetic improvement of native buffalo and cattle is often the goal of programmes for their breeding. This requires a generation-long, consistent effort to improve particular traits. The quality of the semen is an important component of this process. Better quality semen makes it possible for breeders to find bulls with desired features and ensure that these traits are consistently passed down to the next generation. The sexual behaviour of bulls varies among different breeds and is influenced by factors such as age, experience, and the estrous phase of the animal. Factors such as breed, age, and collection intervals can affect semen production traits in bulls. Overall, understanding and managing the sexual behaviour of indigenous cattle and buffalo bulls can contribute to improved semen production and reproductive success.
Keywords: Bull, behaviour, libido, semen, quality
Introduction
Worldwide, a significant amount of frozen sperm derived from carefully chosen bulls with traits including disease resistance, flexibility, and productivity are exported (Butler et al.,2020). These desired qualities can only be attained with superior semen. To address the demand for high-quality semen for breeding, accurate indicators are required and understanding sexual behaviour as an indication may assist in meeting this need (Parkinson et al., 2019).
Seasonal variations in testosterone levels are linked to the seasonal variations in bulls’ sexual activity. Surprisingly, these hormone variations also have an impact on the quantity and quality of sperm (Dixit et al., 1985). Equally significant are the environments in which bulls are raised. Stress, crowding, or poor nourishment may cause them to become less active sexually, which will produce lower-quality semen (Valeanu et al., 2015). The general health of bulls is also very important. Healthy bulls often engage in more intense sexual behaviour, which often results in higher-quality semen production. Conversely, a sick or stressed bull may be less inclined to mate, which would lead to lesser fertility.
To sum up, this article analyses the relationship between bull behaviour and semen quality. Gaining insight into this relationship can have a big impact on breeding initiatives, enhance the genetic makeup of cattle, and advance sustainable agriculture.
Sexual behaviour in bulls:
The male reproductive hormone testosterone is shown to have a significant impact on sexual behaviour. Bulls that are still in tact and have greater testosterone levels display more aggressive and sexual activities. Serum testosterone levels and libido are correlated, suggesting a direct relationship between the two. When bulls engage in normal sexual behaviour are sexually excited, their levels of testosterone and nitric oxide rise; this is not the case for bulls who engage in unwanted behaviour.
The sexual behavior of bulls varies among different breeds and is influenced by factors such as age, experience, and the estrous phase of the cows. Bulls of the Tabapuã breed showed varying levels of libido, with some classified as having low, medium, or high libido. Ongole crossbreed bulls exhibited higher sexual behaviors compared to cows during the estrous phase, including oro-nasal contact, flehmen, mounts orientation response, mounts, and services. Guzerat bulls showed a low response to libido tests, but those with more sexual events were more likely to successfully mate. Angus bulls displayed behaviors such as smelling and licking the genitalia, beating using the head or horn, drip of seminal liquid, erection and penis protrusion, and aborted mount, while zebu breeds exhibited prepuce contraction, aborted mount, and complete mount without end force. Deoni bulls showed good sexual behavior throughout the year, with higher libido scores, shorter reaction times, and shorter mounting times during winter
Bulls’ libido, a critical component, is correlated with faster reaction times as well as higher frequency and intensity of sexual behaviour. Buffalo bulls are categorised for selection using indices of their sexual conduct, particularly their capacity for mating. The most accurate of these indices is the sexual behaviour index.
Bulls’ reproductive success and sexual conduct are greatly influenced by pheromones. Bulls are drawn to buffalo urine during estrus because of certain chemicals including 4-methylphenol and 9-octadecenoic acid, which also trigger reproductive activity. When bulls are exposed to compounds containing pheromones, their heart rate increases, which is an indication of their pheromone response. Buffalo bulls’ sexual activity is correlated with the quality of their semen, which includes sperm motility, viability, and abnormalities. Therefore, it is essential to understand and evaluate the sexual behaviour of buffalo bulls in order to choose bulls with high fertility and improve herd reproductive performance.
Sexual Behaviour and Semen Quality:
Sexual behavior has been found to have an effect on semen quality in bulls. Several studies have shown a positive correlation between sexual behavior and semen quality parameters such as libido score, mating ability score, ejaculate volume, and individual sperm motility. Bulls with high libido have been found to have higher sperm motility and viability, while bulls with low libido have higher sperm abnormality. Additionally, there have been correlations observed between sexual behavior and other semen quality parameters such as sperm concentration, mass activity, and live sperm percentage. These findings suggest that the sexual behavior of bulls can be used as an indicator of their semen quality and reproductive performance. Therefore, evaluating and selecting bulls based on their sexual behavior can be beneficial in improving the reproductive performance of the herd .There is a significant correlation between bulls’ sexual conduct and markers of semen quality. Several studies have shown a favourable link between the volume of ejaculate and scores related to libido, mating ability, and sexual behaviour (Chenoweth, 1983). Subsequent sections discuss the factors influencing sexual behaviour and their consequences on semen quality. Herbal treatment, GnRH therapy, and zinc supplementation improved sexual behavior and semen quality in Karan Fries bulls, suggesting a positive relationship between sexual behavior and semen quality. Libido:
A bull’s libido is defined as his “willingness and eagerness” to participate in mounting and service, whereas his mating ability is his capacity to satisfy this trait. Serving capacity evaluates how many services a bull provides under given circumstances, including aspects of both libido and mating ability. Libido, often known as sex-drive, is an instinctive behavioural attribute that can be difficult to evaluate and explain (Blockey, 1981). It has a major effect on farm animal reproduction, livestock sustainability, and profitability. Studies have indicated that bulls with high libido exhibited higher sperm motility and viability, while bulls with low libido had higher sperm abnormalities.
Environmental factors, bull age, and genetic and management factors all affect libido. Bulls that are older are more likely to experience psychological or physical issues that lower libido. The amount of estrus females in the group, the environment, and group size are all factors that influence desire and the ability to mate (Tomaszewska et al., 1981).
Studies have indicated that when compared to bulls with low libido, those with high libido lick the prepucial area for a shorter period of time, have higher sperm motility and viability, and have fewer sperm abnormalities. (Singh et al., 2019). But there’s a complicated relationship between libido and bull semen quality. According to one study, there are no appreciable variations in the volume, concentration, motility, and viability of semen from bulls with high and low libido. Except for the velocity of the average route (VAP), libido was found to have no influence on pre- or post-thaw sperm quality metrics in another investigation. Because this behavioural assessment is so complex, libido alone may not be a valid indicator of bull sperm quality at AI stations.
The application of estrous-specific molecules like acetic acid, 2-butanone, and oleic acid can improve sexual preparation and semen production in bulls with poor libido. Testicular parameters, such as scrotal circumference, length, width, and volume, are important indicators of reproductive ability in male buffaloes. Non-genetic factors, including age at first semen collection, semen production period, and frozen semen doses per bull, also influence semen production traits in Murrah buffalo bulls.
Additionally, penile erection score and penile protrusion score have been positively correlated with ejaculatory thrust score, mating ability score, and sexual behavior score, indicating a relationship between sexual behavior and sperm motility. Furthermore, ejaculate volume has been found to have a positive correlation with initial progressive motility, sperm concentration, and non-eosinophilic spermatozoa count, suggesting that semen volume is related to sperm motility. Sexual aggressiveness and dismounting time have been positively correlated with penile erection score, libido score, and mating ability score. These findings highlight the importance of sexual behavior in predicting the quality and quantity of semen collected from bulls, as well as the need for proper sexual preparation to ensure successful semen collection . Stressors related to sexual behaviour, such as the transportation of animals for mating or confrontations between bulls, can have detrimental effects on semen quality. Elevated levels of stress hormones can disrupt spermatogenesis and impair sperm function, resulting in a decline in semen quality. Heat stress significantly influences the semen quality of bulls, with effects extending beyond the initial heat stress period due to the response of the hypothalamic-hypophyseal-ovarian axis (Cheng et al., 2016). This leads to diminished sperm quality and fertility in males for several weeks following the onset of heat stress. The adrenal-hypothalamic-hypophyseal-gonadal axis may also contribute to this response. Seasonal variations affect sperm characteristics, such as kinematics, viability, acrosome integrity, and reactive oxygen species, with samples collected in spring demonstrating superior sperm quality compared to those collected in winter and summer.
Environment: Bulls’ physiological processes, such as hormone secretion, energy metabolism, and fatty acid oxidation, can be influenced by environmental factors. Temperature, humidity, and seasonal fluctuations are major contributions to the influence of these elements on the sexual behaviour and quality of semen in bulls. Assuring that bulls’ stalls are well-planned and temperature-controlled has a good effect on sperm quality, output, and bull welfare in general. In Friesian bulls, housing methods, especially loose housing, might affect physiological parameters and seminal quality (Schenk, 2018). Type of semen collection floor also has an effect on sexual behavior and semen quality in Sahiwal bulls. False mounting (a form of sexual behavior) in bulls can improve the quality of semen, specifically in terms of concentration and post-thaw motility.
During the dry, hot summer months, mist cooling and fanning help to lessen the negative effects of high ambient temperature on characteristics of sexual activity and semen quality. Bulls should have a positive experience collecting semen, which calls for well planned locations with good footing, safety precautions, and a distraction-free atmosphere.
Health: Bulls that experience physical harm or diseases as a result of sexual interactions may become less sexually active, which might affect the quality of their sperm. A person’s suitability for artificial insemination may be impacted by health problems that result in inadequate semen parameters. Painless semen collection depends on keeping the hooves in top condition. According to Chand et al. (2016), lame bulls might exhibit reluctance to mount for a variety of reasons, including hoof cracks, laminitis, foot rot, sole abscesses, and incorrect hoof trimming.
Nutrition: The nutrition a mother receives during the peri- and post-conception period can affect her postnatal health, gonadal development, gamete quality, and the hormonal status of her offspring. A mother’s diet during this time, particularly in the periconception and first trimester, might affect the development of the male testis and delay the puberty of bulls, which can ultimately lead to a decrease in the amount of sexual expression and behaviour (Sethi et al., 2022).
Welfare and Sperm Quality
Male animals may become more aggressive and endure elevated stress levels during times of sexual activity. Bulls may become injured as a result, either from other animals or from handlers. In order to reduce stress and aggression during mating seasons, proper handling and management techniques are crucial. Within groups, the sexual conduct of buffalo and cattle bulls has the potential to upend established social hierarchies. Bulls in the dominant position could become more hostile and possessive, which could result in fights.
Bulls in a dominant position may exhibit increased aggression and territoriality, which could result in disputes. The welfare of the herd’s other animals, including subordinate bulls, may suffer as a result of these social disturbances. Breeders and livestock managers face a significant difficulty in balancing the needs for high-quality semen production with the wellbeing of native cattle and buffalo bulls. In order to offset the negative effects of harsh weather on the welfare of bulls during mating, it is possible to create this equilibrium by providing optimal nutrition to bulls throughout the mating season and by ensuring pleasant living circumstances with adequate ventilation and access to shade.
Conclusion:
In conclusion, the welfare and quality of the semen produced by native cattle and buffalo bulls are significantly impacted by their sexual conduct. It demands an all-encompassing management strategy that takes into account the behavioural and physiological requirements of these animals while upholding the strict standards necessary for productive breeding operations. In these valued livestock breeds, optimising both sexual behaviour and semen quality requires careful management techniques and a focus on animal welfare. Overall, understanding and managing the sexual behavior of indigenous cattle and buffalo bulls can contribute to improved semen production and reproductive success.
References
Blockey M D B. 1981. Development of a serving capacity test for beef bulls. Applied animal ethology 7(4): 307-319
Butler M L, Bormann J M, Weaber R L, Grieger D M and Rolf M M. 2020. Selection for bull fertility: a review. Translational Animal Science 4(1): 423-441.
Chand N, Sirohi A S, Tyagi S and Sharma A. 2016. Effect of lameness on semen quality in crossbred frieswal bulls. Bhartiya Krishi Anusandhan Patrika 31(4): 281-284.
Cheng Y, Liu S, Zhang Y, Su D, Wang G, Lv C and Zhang J. 2016. The effect of heat stress on bull sperm quality and related HSPs expression. Animal Biology 66(3-4): 321-333.
Chenoweth P J. 1983. Sexual behavior of the bull: a review. Journal of Dairy Science 66(1): 173-179
Dixit N K, Agarwal S P, Agarwal V K and Dwaraknath P K. 1985. Seasonal variation in serum levels of steroid hormones and their relation with seminal quality and libido in buffalo bulls. Theriogenology 24(3): 293-303..
Parkinson T J and Morrell J M. 2019. Advantages and Disadvantages of Artificial Insemination. In Pages 746–777 in Veterinary Reproduction and Obstetrics. WB Saunders Philadelphia, PA.
Tomaszewska M, Kilgour R and Ryan M. 1981. “Libido” in the larger farm animals: a review. Applied Animal Ethology 7(3): 203-238.
Schenk J L. 2018. Review: Principles of maximizing bull semen production at genetic centers. Animal 12(S1), s142–s147.
Sethi M, Shah N, Mohanty T K, Bhakat M and Baithalu R K. 2022. New dimensions on maternal and prepubertal nutritional disruption on bull fertility: a review. Animal Reproduction Science 107151.
Singh K, Kumar A, Honparkhe M and Singh A K. 2019. Quantification of sexual behaviour traits in presence of teaser male in relation to Libido and semen quality in buffalo bulls. Journal of Animal Research 9(1): 143-146.
Valeanu S, Johannisson A, Lundeheim N and Morrell J M. 2015. Seasonal variation in sperm quality parameters in Swedish red dairy bulls used for artificial insemination. Livest Sci 173:111e8.
