BAP 1 DAIRY CATTLE EXAM
How is milk fever treated?
Calcium barogluconate injections over time.
What are two types of milk proteins?
Casein and Whey
When talking about pregnancy diagnosis, what is a "recheck"?
Check 60 to 80 days after AI to see if pregnancy has been maintained.
What is the difference between clinical and subclinical mastitis?
Clinical mastitis has visible signs while subclinical does not.
What is colostrogenesis? Are milk and colostrum the same? How do they differ?
Colostrogenesis is formation of colostrum. Colostrum is composed of immunoglobulins, vitamins, growth factors, and cytokines. Components transferred in blood. Milk is composed of casein, whey proteins, lactose, and fat.
What is the difference between contagious and environmental mastitis pathogens?
Contagious pathogens can be spread during milking from one cow to another. Environmental pathogens can be contracted from the environment.
What are convention versus accelerate growth programs?
Conventional: Maximize starter grain intake. Accelerated: Maximize milk and milk replacer intake.
How are SNP used in genomic testing to predict future production?
Convey favorability of nucleotide and trait.
What are the main ingredients in dairy cow diets?
Corn silage. Alfalfa. Grain. Protein Supplement.
Know the parts of the 80-day placenta.
Cotyledons (fetal placenta attachment points). Amnion (fluid surrounding calf) Chorioallantois (fluid filled space farther from fetus)
study diagram of estrous cycle
DO IT
study the "life cycle of a dairy cow" diagram
DO IT
When does the fertilized embryo enter the uterus?
Day 5
Be able to describe the hormone and receptor cascade that leads to calving.
Decrease in progesterone, increase in estradiol causes oxytocin receptor expression in muscle of uterus. Uterus contracts and expels calf.
Be able to explain where the building blocks for milk (amino acids, glucose, fatty acids, glycerol) come from during digestion.
Diagram. Basically either breakdown of food product or through chemical processes.
How do you prevent fatty liver postpartum?
Do not let cows get fat during the dry period.
What are the growth rates for heifers before 2 years of age (approximate numbers)
Double weight before weaning. Add 2 pounds a day after that until 2 years old.
What five criteria are used in semen evaluation
Ejaculate Volume, Sperm Concentration, Total Sperm per Ejaculate, Progressive Motility, Morphology
When is colostrum formed and what two hormones are responsible?
Estrogen and Progesterone
What role does FSH play in recruitment, selection, and dominance?
FSH stimulates recruitment process.
What would be a typical incidence of fatty liver, milk fever, ketosis, and mastitis on farm?
Fatty Liver: None Milk Fever: None Ketosis: Less than 10% Mastitis: Less than 2% per month
What are some common symptoms of ketosis?
Few days to few weeks after calving. Low blood glucose. Excess ketone bodies in blood and urine. Lack of appetite. Either lethargy or excitability. Weight Loss. Depressed Milk Production.
What are genetic markers and SNP?
Genetic Markers: DNA sequence that can be used to assess phenotypic variability. SNP: Single Nucleotide Polymorphism. A variation at a single position or nucleotide in a DNA sequence.
Where does glucose come from (what process) in the cow?
Gluconeogenesis in the liver
What two things can be sampled from a cow for genomic testing?
Hair or blood
Define homogenization and pasteurization.
Homogenization: Mechanical mixing so that the milk fat globules are reduced in size and distributed evenly. Pasteurization: Heat to 145 degrees F for 30 minutes to kill bacteria.
What is milk let down? Describe the neuroendocrine loop that leads to milk letdown
How milk gets out of the gland. Nursing/washing causes oxytocin release via brain and blood.
What is hCG? Is a similar test available for cows?
Human chorionic gonadotropin. Human pregnancy test of urine; no
What is milk fever?
Hypocalcemia. Extremely low blood calcium at calving.
Understand: Hypothalamus, Pituitary, gonadotroph, portal blood system, GnRH neuron.
Hypothalamus: Brain region releasing hormones. Pituitary: Gland under hypothalamus. Gonadotroph: Cells that make LH and FSH and secrete into blood. Portal Blood System: Transfers hormones from hypothalamus to pituitary. GnRH neuron: release GnRH as directed by hypothalamus.
What hormones are produced by the hypothalamus and pituitary?
Hypothalamus: GnRH, CRH Pituitary Anterior: LH, FSH, ACTH, GH, PRL, TSH Posterior Pituitary: Oxytocin
Be able to describe hormone changes during late pregnancy that explain the initiation of lactation (lactogenesis).
Increase in glucocorticoids, GH, prolactin, PGF2-alpha, estradiol. Decrease in progesterone.
What is lactogenesis?
Initiation of milk synthesis and secretion.
What is estrous synchronization?
Injecting cows with PGF2-alpha so that they all come into heat on the same day.
Why would you milk 3x versus 2x daily?
It increases milk yield but requires additional management and resources.
What is the DeLaval Herd Navigator System and what does it do?
It monitors progesterone in milk and keeps the data for the herd.
Know the basis for progesterone testing and PAG testing for diagnosis of pregnant and open cows.
Low progesterone is good indicator of not pregnant. Multiple progesterone tests is better. PAG's appear in blood and milk 24 days after breeding. Increase over time.
What are the three functions of oxytocin?
Mammary gland: milk let down. Uterus: Contraction Brain: Maternal and neonatal behavior.
Where do the antibodies in the colostrum come from?
Maternal serum to mammary gland
How do you treat metritis? How do you treat endometritis?
Metritis is treated with antibiotics. There is not treatment for endometritis.
What is milk somatic cell count and what does it tell you about mammary infections?
Milk somatic cell count is the number of somatic cells, mostly neutrophils, in the milk. High SCC indicates mammary infection.
How does starch digestion differ for ruminants and monogastric?
No glucose leaves the rumen of the cow and must be produced.
What is the interval to first ovulation postpartum?
Number of days from calving to first ovulation postpartum. 14 to 28 days.
What is "sire conception rate"?
Number of pregnancies divided by number of breeding with a bull/bull's semen
What's the best way to prevent antibiotic resistance on dairy farms?
Only use antibiotics when there are no other treatment options and only on the quarters infected.
Where does fertilization occur in the female repro tract?
Oviduct
Describe or diagram a parallel parlor, herringbone parlor, and rotary parlor.
Parallel: Cows stand in two parallel rows. Rapid Exit. Milk from back. Herringbone: Diagonal arrangement. All exit from front. Milk from side. Rotary: Cows step on moving circular conveyor. Exit once rotation is complete. Milk between legs.
Why is it important that seasonal calving cows calving in the springtime and get pregnant approximately 80 days after calving?
Peak grass needs to coincide with peak lactation.
What are timed AI (presynch ovsynch) programs?
Programs that assist in synchronization and getting cows pregnant.
What hormones terminate colostrogenesis?
Prolactin and glucocorticoids
How do you treat a cow with ketosis?
Propylene Glycerol via mouth
How do you define puberty in a bull and when does it occur?
Puberty in a bull occurs at about one year and occurs when he produces functional semen.
How do follicles grow at first ovulation (puberty)?
Pulses of LH stimulate dominant follicle. Once enough estradiol accumulates, the follicle grows as this occurs. At puberty, estradiol stimulates LH surge and produces egg in ovulation and follicle becomes corpus luteum = estrus
What are recruitment, selection, and dominance?
Recruitment is the appearance of many follicles. Selection is the determination of the superior follicle. Dominance is the growth of that ovulatory follicle.
Name the diseases that affect the postpartum uterus.
Retained Placenta. Metritis.
What is "gender selected semen"?
Semen sorted to produce female offspring.
What is the standard lactation length? When does peak lactation occur? What is persistency?
Standard lactation length: 305 days. Peak Lactation: 2 months Persistency: Decrease in yield from peak to dry off.
What is the difference between stroma and parenchyma in the mammary gland?
Stroma is supportive connective tissue. Parenchyma is glandular secretory (milk producing) tissue.
What are your options for testing a cow for ketosis?
Test urine or blood and milk BHB testing.
Understand how a milking machine works
The claw or cluster holds milking cups for teat. In milking phase, inflations (soft rubber in machine) is relaxed due to vacuum application to both tank and teat and milk is sucked out. In rest phase, vacuum causes inflation to collapse and milk refills in gland cistern.
What are the two worst days in a cow's life?
The day she calves and the day you dry her off.
What is a follicular wave?
The process by which we go from many follicles to one ovulatory follicles
Why is Vitamin D added to milk?
To increase calcium absorption and prevent the childhood disease rickets.
Be able to explain why cows get fatty liver postpartum.
Too much weight loss postpartum leads to fatty liver. NEFA's accumulate in liver and cannot be processed.
What are triglycerides, glycerol, and NEFA?
Triglycerides are lipids. Glycerol and NEFA are what triglycerides break down into. NEFA is nonesterified fatty acids
What is lactose?
Two molecules of glucose are used in the production of one molecule of lactose.
what are the highest exports for US, Ireland, NZ?
US: cheese Ireland: butter NZ: milk powder
What is the "Dairy Matrix"?
Unique combination of nutrients and bioactive factors which interact with each other to produce the overall effect on health.
What is uterine involution? How long does it take for the uterus to completely restore normal fertility?
Uterine Involution: Process that the uterus undergoes to shrink back to normal size and repair itself after calving. The process takes about 60 days.
Where is semen placed in the repro tract when a cow or heifer is AI?
Uterine body
Be able to define or explain VWP, days open, and calving interval.
VWP: Voluntary Waiting Period. Around 60 days after calving where the cow is not bred. Days open: Days cow is not pregnant. Calving Interval: 13 to 14 months. Time from one calving to another.
What are the four major components of milk?
Water. Fat. Protein. Lactose. (Ash)
What are the symptoms of milk fever?
Weak to down cow, close to or after calving. Cold extremities. Normal to low temperature. Bladder is often full and manure often dry.
Why is ketosis (elevated BHB) associated with low blood glucose postpartum?
With low blood glucose, more Acetyl CoA accumulates in the liver causing ketosis. Low blood glucose could be indicative of a lack of propionate used to form glucose and use Acetyl CoA for citrate production.
what is automatic feeders? mob feeders?
automatic: measures out correct amount of food and drink for individual in group housing mob: nipples around central barrel for water and available food
what are the three largest dairy states? what is the fastest growing state?
california, Wisconsin, New York. texas
what is "dairy beed" and why do you breed dairy cows to beef bulls?
dairy beef is a black beef cross cow. holstein cross beef sire.
What hormone must reach a threshold concentration to cause first ovulation (puberty)?
estradiol
what are the major qualities of the 2 major breeds?
holstein: high milk volume jersey: high percent fat and protein
what are the components of selection index in the USA?
milk production (40%), reproduction (30%), health (30%)
what is stress versus strain for dairy cows?
stress: how much milk is produced strain: sickness/death/damage (high stress, low strain is what we want)
Know the stages of early embryonic development from one cell to tubular embryo.
1 cell, 2 cell, 4 cell, 8 cell, 16 cell, morula, blastocyst, hatched blastocyst, spherical embryo, tubular embryo
How long does it take to milk a cow?
10 minutes
How many sperm cells does a bull produce each second?
1000 per/sec
what is the average milk production per lactation per cow in the USA?
10522 kg/23197 lbs
when does first breeding occur in a dairy heifer? first calving?
13-15 months 22-24 months
Be able to describe the hormones and structures involved in mammogenesis ( development of mammary gland).
1: Ductal growth and branching. Involves estradiol and progesterone. 2: Development of alveoli. Involves prolactin.
What are three important things to know about PGF2α treatment for estrous synchronization?
1: It will not regress the CL during the first 5 days of the estrous cycle. 2: Heifers in heat 2 to 3 days after treatment. 3: Cows in heat 3 to 5 days after treatment.
What are the three steps to dry off a cow?
1: Milk the cow. 2: Selective dry cow treatment with antibiotics. 3: Orbeseal (seal teat cistern)
how many days in estrous cycle?
21 days
When (day of pregnancy) can you test for PAG and where do you look for them?
24 in blood. 28 better in blood and milk.
How much glucose does a typical cow synthesis in the liver daily?
3.6 kg of glucose
what is a "replacement rate" for dairy?
30%
How do you manage a cow for second insemination?
32 days after first AI, give the cow GnRH. 7 days later, do a pregnancy diagnosis and if not pregnant give PGF2-alpha. 3 days later give GnRH and AI for second time.
When do you do pregnancy diagnosis postpartum?
39 days after first AI
What % of a group of heifers should be in heat on one day?
5%
How many SNP are used in a typical genomic test?
50,000
How many daughters did Toy Story have?
500,000
What are growth targets for heifers at first breeding and first calving?
55% of mature weight at first breeding. 85% of mature weight at first calving.
how many dairy cows are in the US?
9.4 million
What is interferon tau and how does it act to maintain the CL?
A hormone that blocks PGF2-alpha release and rescues the CL to maintain progesterone and pregnancy.
What is a "negative DCAD diet" and how does a negative DCAD diet prevent milk fever?
A negative DCAD diet is a diet that contains more anions than cations. It increases parathyroid hormone receptors which leads to greater intestinal and bone calcium absorption.
What is negative energy balance? What three things are used to calculate energy balance?
A negative energy balance occurs when milk production exceeds dry matter intake and cows lose weight. Energy balance equals feed minus milk requirement minus maintenance requirement.
When (relative to estrus and ovulation) do we AI heifers and cows? Why?
AI 12 to 16 hours after entering heat. Want sperm to mature and move to oviduct before ovulation at 30 hours.
What's in a semen extender and what are the functions of the various components?
Allows semen to be stored for later use. Milk or egg yolk base (protect during cooling). Salt (isotonic). Buffer. Glucose or fructose (energy source). Antibiotic (prevent bacterial growth). Glycerol (Protect sperm during freezing)
What is follicular atresia?
Arrested (stop developing) follicles that die and do not ovulate.
Where are the hypothalamus and the pituitary located?
At the base of the brain.
Be able to describe the aveoli including important cell types.
Aveoli are milk secreting epithelial cells. Duct system transports milk. Lobules and lobes are clusters of alveolar tissue supported by connective tissue.
What is BCS (1 to 5 scale)? What are the expectations for BCS loss and gain during lactation?
BCS is Body Condition Score in dairy used to determine appropriate condition and maintenance changes. Cows should lose some BCS from calving and early lactation (3.25-3.50 to 2.75-3.00) and gain BCS after peak milk (2.75-3.00 to 3.25 to 3.50).
What role do bacteria, protozoa, and fungi play inside the rumen?
Bacteria digest fiber, simple sugars, and proteins. Protozoa consume and digest bacteria and digest starch, sugars, and proteins. Fungi breakdown cell walls.
Define blastocoel, inner cell mass and trophoblast.
Blastocoel: Fluid-filled cavity in blastocyst. Inner Cell Mass: Mass of cells that will become the fetus. Trophoblast: Tissue on outside of blastocyst.
What is lipolysis?
Breakdown or loss of fat.
