Module 3 Management Of Ruminant Breeding Stock Flashcards
is probably the single most important factor affecting the economics and profitability of beef cattle breeding operations.
Reproduction
what is reproduction for bulls?
is all about the capacity and ability to sire a large number of viable offspring in each mating year.
What is reproduction for cow?
reproduction is all about the capacity to conceive and rear a calf to weaning each year
following puberty.
forms the basis of livestock improvement as it allows the transfer of genetic material from one generation to the next and can greatly influence genetic gain.
Reproduction
after successful mating it follows whereby the egg is fertilized by sperm
conception
conception is followed by what? Whereby the fetus grows inside the uterus until birth/calving.
Pregnancy or gestation period
calving intervals of cow
365 days
The basic production cycle for cattle
9 months gestation period
Birth on grass
Calf stays with cow until weaning
Being put with peers to grow until reaching finishing weight
At weaning calves are giving what?
Given injection
Tags
Castrated
Branded
Most of this cow will have a calf every year until they are culled for low performance
Brood cows
Many factors influence and can impact on reproductive performance
Improved management of reproduction
Nutrition
Genetic selection strategies to improve profitability
Focusing selection on the economically important criteria and traits related to fertility
Percent of improvements in weaning rates that are possible through improving nutrition
5-10%
Reproductive function can be improved by what?
focusing selection on the economically important criteria and traits related to fertility.
Is influence by a number of independent traits
Reproduction performance
Reproductive Measures for the bulls include:
Physical and structural soundness
Scrotal size and sperm production capacity
Semen quality, including morphology
Serving ability/ serving capacity
Reproductive Measures for the cow include:
• weight and age at first estrous cycle
• the inter-calving interval
• lactation status at subsequent pregnancy diagnosis
Reproductive Measures for the breeder herd include:
• branding and/or weaning rates
• kilograms of calf weaned per 100 kg of cow mated.
• conception rates determined by pregnancy diagnosis (PD)
Limitation of reproductive measures
• fertility cannot be assessed directly for bulls.
• pregnancy status for cows requires skills in pregnancy diagnosis, which should be coupled with an assessment of lactation status.
• branding and weaning rates (in isolation) do not provide indications of when or where reproductive losses may be occurring.
• unless birth dates are known and a restricted joining period used, a slight ‘creep’ in inter-calving interval can often be overlooked.
• it is important to consider that these rates must be calculated for a standard or specific period of time (e.g., 12 months) to allow accurate analysis and comparison
Should be coupled with an assessment of lactation status.
Skills in pregnancy diagnosis
Why it is important to consider that these rates must be calculated for a standard or specific period of time (e.g., 12 months)?
Allow accurate analysis and comparison
it requires a satisfactory physical examination and minimum values for scrotal circumference, motility and morphology.
Satisfactory potential breeder
any bull not meeting minimums is classified either as?
Unsatisfactory potential breeder
Classification deferred
minimum recommended morphology of a sperm
70% normal cells
primary sperm abnormalities
• underdeveloped
• double forms
• acrosome defect
• narrow heads
• crater/ diadem defect acrosomal
• pear-shaped defect
• abnormal contour
• small abnormal head
• free abnormal head
secondary sperm abnormalities
• small normal heads
• giant and short broad acrosome
• free normal head
• detached, folded, loose membranes
• abaxial implantation
• distal droplet
• simple bent tail
• terminally coiled tail
were identified as most important culling criteria for beef bulls.
Physical unsoundness
Infertility
it is the most important trait of a bull
bull’s fertility
is an integral part of bull’s fertility. The bull’s ability to remain fertile is dependent on this
physical or structural soundness
. the way it grows often indicates structural problems higher up the legs.
Claws of the feet
may indicate too much or not enough pastern angle, causing both claws of the
hoof to grow or wear excessively
it affects the mobility and performance of the animals
overgrown claw
the feet structure should avoid this
overgrown, scissor or curved claws
overgrown, uneven claws are usually indication of what?
Poor limb structure or early sign of hip arthritis
The degree of the angle in the leg joint is less than ideal
sickle hocked
when the hocks are rotated inwards and the hooves rotated outwards
cow hocked
it should be trim and close to the body
sheath
is housed within the prepuce and sheath
penis
is the inner lining of the sheath and is pink mucosa, seen at the end of the sheath.
Prepuce
major factors influencing scrotal size
genotype
age
liveweight
nutrition
timing of nutritional stress
Common conditions that interfere with fertility and can be diagnosed by palpation of include:
unequal size of testicles
hardness of one or both testicles
thickened scrotal skin.
softness and flabbiness of testicles and tail of epididymis
Bull wastage can be due to factors that includes:
Structural defects resulting in lameness; inability to serve
Degenerative conditions limiting serving ability
Age structure in the bull team
Reproductive abnormalities
Infertility due to testicular degeneration
Infertility due to disease effect
Traumatic injuries due to fighting
Veterinarians should carry this examination
• Checking the bulls overall structure including legs, feet and external reproductive organ are free from defects
• Assessing the sheath, scrotum and testicle
• Measuring and recording scrotal circumference to ensure it is within the acceptable limit
• Palpating of the testicle to check for normal tone, size and function
• Collecting a semen sample and do microscopic examination
Sign of estrous
Behavioral changes
Swelling of vulva and vagina
Vaginal mucus discharge adhering to tail and legs
Abrasion of skin
Ruffling of tail hair
Increased tone in the uterus and cervix on palpation
The length of estrus is affected by:
Breed
Nutrition
Temperature stress
Age
Transport stress
Ovarian abnormalities
Uterine infection
Average duration of estrus
6-18 hours
The embryo leaves the fallopian tubes and enters the uterus at about how many days.
Six or seven days
Duration of pregnancy in cattle ranges from what?
270 to 290 days
Four major categories of breeder
Wet and pregnant
Wet and empty
Dry and pregnant
Dry and empty
It tends to conceive early in the season as they are in better body condition and the lactating cows conceive
Dry cows
Reproductive cycle is prolonged longer than 35-45 days after calving
Post-partum anestrus
Is the most important non-genetic factor influencing conception in beef cows.
Nutrition
Are the key determination on age at first joining
Growth rates
Five point scale for condition scoring
Emaciated
Thin
Moderate
Good
Fat
2 practical techniques in reducing energy requirement
To reduce the nutritional trough by the use of supplement
Weaning
Will be needed to sustain the young weaner so it feed the weaner so it suffer no disadvantages from having its milk supply terminated
Bypass protein
Why genetic of the herd is worthwhile
Cheap
Permanent
Cumulative
In inter-calving interval it is often be over-looked
.
Creep
Most Disease carried by bull
Vibriosis
Trichomoniasis
Rhinotracheitis
Puberty in bulls
18-24 months
Calf output
Number of mounts
Mounts plus serves
Libido score
Is the most important semen characteristic of a bull going into natural mating, and is an accurate forecast of his paddock fertility
Percentage normal sperm
Is the most important criterion in assessing bull fertility
Scrotal size
Integral part of bull’s fertility
Physical soundness
This means bulls may not contribute significantly to the herd productive rate , and thus do not pass on their desirable growth or carcass traits
Sub-fertility
In tropical beef it is the major factor influencing puberty
.
nutrition
Desired weight of cattle
280-300kg
Ovulation occurs in what hour after the end of estrous
10-15 hrs
Behavioral estrus may recommence at what day?
.
35-45 day
Duration of pregnancy in cattle?
.
270-290
Tend to conceive early in the season as they are in better body condition
Dry cows
. Ater calving the reproductive tract and ovaries of a cow should return to normal and reproductive cycle commerce
Post calving
Prolonged cycling after parturition
Post-partum anestrus
The single most important determining factor in reproductive management and getting cow back in calf.
Condition score
Will reduce the energy requirement of the dam by almost half
Weaning of calf
Involves mating period by removing the bulls from the breeding herd
Seasonal or Controlled mating
Culling emphasis on what?
Fertility and functionality
Occurs when one member of a gene pair masks the effect of the other member of the gene pair.
Complete dominance
When there is intermediate outcome between the two effect
Partial dominance
Difference of individual within a population
Variation
. Is defined as proportion of superiority in a trait that is transmitted to the offspring
Heritability
. Difference between the mean of those selected to be parents and the mean of all potential parents.
Selection differential
This is the average age of the parents when offspring are born or in simple terms, the time interval between the same age in the life cycle of two successive generation.
Generation interval
Means that large portion of young animals are introduced each year, leading to large culling of older animals
Short generation interval
. Measures of genetic differences between animals, expressed as the unit for each trait in positive and negative term.
.
Estimated breeding values
Dedicated software to find the best fit for all pieces of information, for all traits in question and all the animals in the analysis simultaneously
blup
. Not closely related, within same breed.
Outbreeding
Mating of the animals belonging to two different breed
.
Cross breeding
Mating of unrelated pure breed animal
Out crossing
. Is the system of breeding mostly used for genetic improvement of cattle?
Cross breeding
Is the method used for genetic improvement of buffaloes
.
Grading up
Is implanted into the ear.
.
Growth stimulating implant
Feed additive often use on cow-calf operation
Antibiotics
Is approved for treatment of bovine respiratory disease complex and prevention of anaplasmosis.
.
Chlortetracycline
Are special type of medical feed additives called ionophores
Monensin
Lasalocid
Its mode of action is to change the microbial population of the rumen. Selective against certain bacteria and protozoa.
Ionophores
Commonly found in feedlots
Monensin
Commonly used in cow-calf and stocker operation
Lasalosid
Dewormers available as top-dresser
Anthelmintics
As feed additive to suppress horn flies
Larvacides
Stops the normal hormone production sequence that produces estrus
Melengestrol acetate
. New to feedlot cattle increase lean disposition and weight gain
Beta-agonist
Sustaining a higher ruminal PH under concentrate feeding to prevent sub-acute acidosis,
.
Direct fed microbial
Are structures that are moderately heritable
.
Leg and foot
Why is it that scrotal size is a useful criterion for assessing bull fertility
It is easily measured and is repeatable,
It is related to a bull’s own fertility,
Finally, it is genetically correlated
It is examined under a microscope to assess factors such as volume, color, density and motility.
Crush side
Is the sexual desire of male to serve a receptive female.
Libido
Part of the breeding soundness examination enables farmers to first identify bulls that are able to serve while reducing the risk of bull failure in single sire mating. It is also a measure of the sex drive
.
Serving capacity test
Puberty in bulls is achieved in how many months
14-18 months
Factors influencing when bulls reach puberty include:
.
Genetics effects
Nutritional influences
Often have fat deposits in the neck of the scrotum
.
Bulls fed on grain diets
Those having surplus protein and energy
Can produce swelling of the joint capsule of the hocks in some bulls.
Grain diets
Reproductive in females is hormonally driven and influence by what?
Nutrition
Genetics
Management factor
Puberty in female define as what
As the age at first estrous when ovulation also occurs/onset of sexual maturity
115
116.
. Average duration of estrus
6-18 hrs
The exact timing of different breeding activities will depend on what?
Location
Seasonal condition
Management system
At peak lactation a cow will need up to how many energy and protein ?
Twice energy she does as a dry cow and up to three times the protein
This can place the lactating cow under such stress that she has difficulty in maintaining nutrient supply for reproductive function with a consequent reduction in fertility. In some cases the cow may even die as hormonal regulation
Nutritional demand and nutritional availability
Are naturally correlated with pasture quality and availability In younger cattle
Growth rate
The best practical assessment of nutritional needs of reproducing beef cows
Assessing changes in body condition score
. Options to achieve good body condition score
Supplementation
Grazing management and adjustment of stock rate
Paddock rotation
Weaning to reduce nutritional demand for the breeder
Are the most economical means available supplements
Protein supplement especially non-protein nitrogen supplement such as urea-based mixes
Is the most practical form of supplementation of the breeder cow
Weaning
Are the most difficult breeders to get back in calf as they are still growing as well as producing milk
First-calf heifers
Maiden heifer with additional protein in the later stages of their pregnancy will improve conception rates after they calves.
Spike -feeding
. This is the difference between the mean of those selected to be parents and the mean of all potential parents.
Selection differential
- Is the average age of parents when their offspring are born or in simple terms, the time interval between the same age in the life cycle of two successive generation.
.
Generation interval
This process has limited use in achieving improvement in most production traits and it has minimal value in selecting for cascass traits. It can also used to asses phenotype and this also happens in isolation from knowledge of the environment effects that the animals has undergone
Visual selection
- The solution provides the best estimate of the genetic merit of the animals
Best linear unbiased prediction
- This program that provides a genetic description of cattle for a range of traits in the major are of growth, carcass performance, and fertility. It is where common sire linkages occur with other groups, comparison can be made across groups.
Breed plan
- Allows comparison of animals across herd-most reported EBV
GROUP BREED PLAN
Have proved a good guide to the performance of animals in a commercial herd enterprise.
Breed plan EBV’s
Describe the profitability of animals based on the summation of their individual traits or EBVs.
markers
Index selection results
. Can be used to customized a selection index for the producer’s particular situation
.
Breed Object
Is an amalgamation of all available EBVs using appropriate weighting calculated for individual beef producers in different environment, targeting different market .
Index selection
They give the industry the potential to identify and select animals for specific traits at an early age.
Gene marking
It lowered production in terms of milk yield and fat %, increased susceptibility to disease resulting in more mortality.
Inbreeding
Breeding the farm animals which are not closely related withing the same breed . Most popular in breeding the dairy herds.
Out breeding
Mating of the unrelated pure breed animals within the same breed.
Out crossing
Mating of the animals belonging to two different breeds.
Cross breeding
- Offers maximum individual heterosis and maternal heterosis
.
Triple crossing
Are often used for very temporary identification
Paint brands and stick on tags
Is widely used by breed registry association and cowherd performance testing program as a method of a permanent identification
Ear tattoo
Is second in use to the ear tattoo as a permanent means of individual animal identification usually applied with a hot iron
Number brand
Most widely used method of temporary identification
Soft-type plastic ear tags
Bloodless methods of castration
Emasculating or clamping
Elastration
Is the practice of providing supplemental feed, usually grain, to nursing calves in a facility that prohibits the brood cow from having access to the feed.
Creed feeding
