Outline :
•Introduction to breeding bull
•Objective of breeding bull
•Points to considered while selecting a breeding bull
•Necessities of care and management of breeding bull
•Procedure of care and management
•Obstacles in care and management of breeding bull and solutions
•Health and disease
Introduction :-
Proper management and nutrition of bulls is essential to ensure cow producers maximize efficiency and genetic improvement of the calf crop. In addition, the herd bull influences overall herd fertility more than any other single animal, and loss of fertility by a bull can cause substantial loss to a potential calf crop. Each cow produces one calf per year; however, bulls should contribute to the calf crop by 25 to 60 times via siring 25 to 60 calves. Additionally, bulls influence their daughters’ production in the cow herd. Therefore, bull selection can be the most powerful method of genetic improvement in the herd, but bulls with low fertility, structural problems and low libido reduce the percent calf crop weaned. The number of cows bred during the breeding season plays the largest role in percent calf crop weaned, and percent calf crop weaned is the single most important factor influencing profitability in beef operations. The weaning weight is influenced by the bull selection. Since greater than 90% of the beef cows in the United States are bred by natural service, it is important that bulls be managed to optimize breeding performance. Producers spend the necessary time to find quality bulls based on EPD’s, but how is the bull managed from purchase to breeding or between breeding seasons can affect the longevity of a bull? Has the nutrient requirements of the bull(s) been met during these periods or are the bulls placed into a pasture to be forgotten about until the next breeding season? There are several factors that influence bull fertility. First, a bull must be developed properly and have reached puberty to be fertile. Second, physical characteristics, such as scrotal circumference, mating ability, and semen quality play a role in a bull’s fertility. Third, libido and social dominance influence a bull’s ability and desire to service cows. This paper will start with nutrition.
•Breeding bull means a male animal of dairy or beef bovine genus used for breeding purposes
•It is the selected mating of individuals to produce a calf that is desirable or of scientific interest
•A bull also known as a sire, is a mature male bovine that is atleast two years old used for breeding purposes
Objective of breeding bull
• A breeding Bull of cattle and buffalo offspring received 50% inheritance character
• Bulls provide the biggest proportion of calf genetics, so it is important to select a herd sire that can produce desired offspring.
•A bull of good quality gene can produce calf of highly improved genetics and helps in the increment of good generation .
•A bull can detect and ensure the heating period of female bovine
Culling :culling is process of removing or segregating animal from a breeding stock based on specific trait .
Reason for culling the breeding bulls is as :
➢Low pedigree record
➢Poor semen quality
➢Lack of sexual libido
➢Disease
➢Old Age
POINT TO BE CONSIDERED WHILE SELETION A BREEDING BULL :
1.Selection of bull
➢It’s depend on age ,breed ,type , and according to pedigree record help condition and daily conformation .
➢Bull should be true to type of breed character . ➢It should be healthy , masculine and vigorous .
➢It should be free from physical deformities and defect
➢Examine the quality and quantity of bull semen ,very often to ensure its effective potency .
➢Acclimation to the environment .
Selection :-
▪The breeding bulls should be selected from good pedigree
▪The bull should be sound in structure and must have good performance record
▪The bull must have a good genetics
Breeding soundness Evaluation (BSE)
Theriogenology developed minimum guidelines for a bull to pass a BSE.
• It includes :
1.Physical examination
The American Society for Theriogenology developed minimum guidelines for a bull to pass a BSE. A BSE includes a physical examination, measurement of scrotal circumference, and evaluation of semen quality. To successfully complete a breeding soundness evaluation, a bull must have at least 30% sperm motility, 70% normal sperm morphology, and a minimum scrotal circumference based on age (Table 1; Chenoweth et al., 1992). Bulls should be tested approximately six weeks to one month prior to the breeding season by a veterinarian. This allows for time to retest bulls where unsatisfactory results are obtained or time to find a replacement herd bull. Table 1. Minimum scrotal circumference requirements for bulls to successfully pass a BSE based on the age of bulls (Chenoweth et al., 1992). Minimum scrotal circumference requirements based on age Age in months 15 > 15 18 > 18 21 > 21 24 24 Scrotal circumference (cm) 30 31 32 33 34 Mating Ability The purpose of the physical examination portion of a BSE is to determine a bull's mating ability. Mating ability can be described as the physical capabilities needed to successfully breed a cow. A bull must be able to see, smell, eat, and move normally to successfully breed cows. The physical examination closely scrutinizes a bull’s eyes, teeth, feet, legs, and nutritional level (evaluated by body condition score). Any disease or injury that affects.
2. scrotal circumference
Minimum of 30 cm in 1 year old bull
Minimum of 33 cm in 2 year old bull
As scrotal circumference increases, so does the daily production of high-quality sperm. There is a positive genetic correlation between a sire’s scrotal circumference, the scrotal circumference of his sons, and the pregnancy rate of his daughters. Furthermore, a negative genetic correlation exists between a sire’s scrotal circumference and age of puberty in his daughters. This indicates that bulls with a larger scrotal circumference will likely sire sons with larger scrotal circumference. Furthermore, daughters should reach puberty at younger ages. There are two commonly used methods for measuring scrotal circumference, a scrotal measuring tape or the Coulter scrotal measuring tape. Scrotal circumference is measured by placing a measuring tape around the scrotum at the widest point and measuring the circumference of the scrotum. A scrotal circumference measurement is an indirect estimate of the mass of testicular tissue; moreover, amount of testicular tissue is directly related to sperm quantity and quality. Studies on 1,944 bulls of various breeds and ages indicated that as scrotal size increased, the probability of a bull passing a BSE also increased (Cates, 1975). Additionally, bulls with small scrotal circumference at a year of age tended to have small scrotal circumference at two years of age.
Semen Quality
Semen quality includes ejaculate volume, sperm cell motility, and sperm cell morphology. It is important to remember that substandard nutrition, extreme environmental temperatures, and disease can reduce semen quality, and that the quality of semen from a single bull may change over time. Sperm motility is calculated by evaluating the percentage of spermatozoa in a sample ejaculate that have progressive (headfirst) movement under a microscope. Sperm morphology is calculated by evaluating the percentage normal spermatozoa in a sample ejaculate compared to sperm with primary and secondary abnormalities. Primary abnormalities originate in the testis during spermatogenesis. Secondary abnormalities originate in the epididymis, during sperm transport, or with handling of the sperm. Primary and secondary abnormalities refer to the origin of the defect and not to the severity of the defect. Therefore, both primary and secondary abnormalities are equally important when evaluating sperm quality.To successfully complete a breeding soundness evaluation, a bull must have at least 30% sperm motility, 70% normal sperm morphology .
Necessities of care and management of breeding bull
•Breeding bull have a major effect on herd fertility
•To optimize the breeding performance of bulls
•It can help in genetic improvement of calf
•It can increase the profitability and sustainability of the farm
•It helps in maintenances of good quality semen
Feeding :-
▪The properly balanced ration should be given which contains adequate energy ,protein , minerals and vitamins
▪Mature bull should be fed adequately to keep it on good flesh but not over fat
▪Sufficient amount of green feed , 1kg of good quality hay (DM) and 1.5 kg of concentrates per 100 kg of body weight per day will keep in good breeding condition
▪For a 400kg breeding bull , 7.5 kg of dry feed , 250gm Dicalciumphosphate (DCP) , 4.2 kg total digestive nutrient (TDN), 15.4 Mcal metabolizable energy (ME) , 18gm calcium , 13gm phosphorus, 40mg carotene. This
helps to improve the semen quality of bull
•When berseem/lucerne/cowpea are available they can be fed along with the straw or other good quality roughages like oats without any concentrate. However, when straws form the basal ration, concentrate are to be fed.
•When non-leguminous green fodders, like oat, maize, sorghum, good grazing etc, form the basal roughage there is no need to feed concentrate mixture.
Management :
Ringing of bull :
•For convince handling and protection from a viscous bull a nose ring of convenient size of about 2.5 “diameter should be fixed at the age of year .
•Nose ring should be made from nonrusting metal of uniform thickness ,copper ring are better.
Training of bull :
•For leading of bull , bull –leader or bull holder should be used.
•In case it is regularly tied in the pen a strong halter may be used .
•Bull should be trained at an early age ,so that they can safely handled and easily teachable at this age .
Disbudding of a bull calf :
•For a safe handling the bull may be kept without horns a bull is dangerous under most circumstances but less if it is dehorned .
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Pen housing :
▪This system is best system for breeding bull .
▪It provide ample space of 12 x 12 or area 14 x 15 sqft .
▪It should have ample shed to protect from intensive sunlight and good to protect from cold and rain .
▪The stall should open into strongly fenced paddock into which the bull has access and movement
▪The pen should have stanchion to which the bull can be tied during cleaning time
▪The feeding and watering arrangement should be made in the pen and paddock
Housing pen for breeding bull :-
Exercise :
▪ Moderate daily Exercise is needed to keep active , normal appetite, retain breeding power and good health
▪ Bull Exercise done in exercise ring .
▪Bull may be tied to his chain which allows to walk up to the length of chain .
▪Males which received plenty of exercise produce larger ejaculation containing more sperms of higher activity ▪Teasing of bull should be avoided .
▪Paddock should be cleaned daily to avoid slipperiness .
▪Routing vaccination and deworming schedule should be followed.
Exercise ring :
Care in handling of viscous bull :
•Give sufficient exercise
•Avoid solitary confinement •Regular feed supply Miscellaneous :
➢Brushing and grooming is advisable in morning hours
➢The bull should be handled by different person so that it will not have habit of handling by one person ➢The bull washed frequently .
Disposal of bull :
➢Bull can be used to service up to 12 year of age
➢After this day become uncertain breeders , therefor older bull should be culled or sold . Services:-
▪An experienced bull (greater than 2 years of age) that passes breeding soundness exam should easily service 30 females in 60 -70 days and inexperienced bulls( less than 2 years of age) 15-20 female in 60-70 days in breeding season
Health and disease :
•Maintaining the health of breeding bulls is crucial to ensure successful reproduction and healthy offspring.
•Common health issues in breeding bulls include
❖respiratory infections
❖ foot rot
❖ reproductive disorders
•It is important to monitor the health of breeding bulls closely and seek veterinary care at the first sign of illness.
Prevention measures :
•Regular vaccinations
•proper nutrition
• good hygiene practices
•Vaccinations can protect against common diseases such as pneumonia and foot-and-mouth disease.
• Good hygiene practices, such as keeping living areas clean and dry, can also help prevent the spread of disease.