Cow Main Points - Dr. May Flashcards
Dr. May's NB for the Final
1
Q
Basics of Bovine reproductive physiology?
A
- Polyestrous
- Puberty ⇒ 10 m. (avg.)
- Estrous cycle ⇒ 21 d. (avg)
- 2-3 follicular waves of 7-10 d. duration each
2
Q
What 2 hormones peak during the Follicular Phase of the Bovine estrous cycle?
A
- LH (highest)
- E2
3
Q
Which hormone peaks during the Luteal phase of the Bovine estrous cycle?
A
Progesterone
(P4)
4
Q
Which cells, in the Bovine, become Large Luteal Cells?
A
Granulosa cells
5
Q
Which cells, in the bovine, become Small Luteal Cells?
A
Theca cells
6
Q
What is the size of the bovine follicle at ovulation?
A
2 - 2.5 cm
7
Q
Describe the uterus of a cow in Estrus.
A
- Marked uterine tone
- Thick mucosal discharge
- Vulval edema
8
Q
What is the duration of Estrus in the Bovine?
A
8-12 hrs.
(Max = 24 hrs)
9
Q
When does ovulation occurs in the Bovine?
A
12 hrs after the END of Estrus
10
Q
What two parts of the Estrous cycle make up the Follicular Phase in the Cow?
What is their duration?
A
- Estrus ⇒ + 24 hrs.
- Proestrus ⇒ + 2-3 d.
11
Q
List the durations of the 4 phases of the Bovine Estrous Cycle.
A
- Estrus ⇒ d. 0 -1
- Metestrus ⇒ d. 1-4
- Diestrus ⇒ d. 4-18
- Proestrus ⇒ d. 18-21
12
Q
What 2 parts make up the Luteal Phase of the Bovine Estrous Cycle?
A
Metestrus & Diestrus
13
Q
What is the primary goal of reproductive management in cattle?
A
Improved economics
14
Q
What is the ideal dairy management scheme?
A
- Ideal calving interval ⇒ 1 calf per yr.
- Days in Milk (DIM) ⇒ 305 d.
- “Dried off “ & rebred = 60 d.
15
Q
What is the most important management aspect of “Dry” cows going through the transition period?
A
Nutritional management ⇒ critical to prevent ketosis or hypocalemia
16
Q
What is the Voluntary Waiting Period (VWP)?
How long does it typically last?
A
- period the farmer waits after calving before
rebreeding his cows - Usually 45-60 d.
- Uterine involution takes 45 d.
- Will be delayed if any calving complications occured
- Uterine involution takes 45 d.
17
Q
Define “Days open” (a.k.a Calving to Conception Interval).
Why do we care?
A
- Period from which the cow calved to when she is confirmed pregnant.
- Peak lactation occurs ~ 45-90 d. post parturition
18
Q
What is the primary cause of poor reproductive performance on dairies?
A
Poor heat detection!
19
Q
When do you perform the post-partum evaluation?
A
25-30 days after calving
20
Q
When do you perform the pregnancy exam?
A
5-6 wks. post breeding
21
Q
What is the target calving interval?
A
12-13 months
22
Q
What is the target number of “Days open”?
A
90-100 days
23
Q
What is the target # of services per conception?
A
2 - 2.5 services per conception
24
Q
What is the target # of days to 1st service?
A
70-75 days
25
Why do we perform estrous synchronization in cattle?
* To synchronize estrus for A.I.
* reduce the work load on the staff
* To synchronize estrus for Embryo transfer
26
**Describe the Ov-synch program for Estrus synchronization.**
* Most commonly used protocol in the U.S. dairy herds
* Goal is to manipulate the CL
* GnRH ⇒ any point in the cycle
* Ovulation of dominant follicle _OR_
* New follicular wave
* PGF2a ⇒ 7 d. after GnRH
* Luetolysis
* 2nd injection of GnRH ⇒ 48 hrs. after PGF2a
* Ovulation of the Dominant follicle
* A.I. 24-33 hrs. later
27
When will 1 injection of PGF2a cause luteolysis of the CL?
\> D. 5-6
CL has to be old enough to display PGF2a receptors
28
When will a cow come into Estrus if given PGF2a after d. 5-6?
W/in 1-7 d.
(depends on the type of the follicles present: dominant vs. earlier ones)
29
How many days apart do you give PGF2a if you are using 2 shots to synch your herd?
Why do we prefer this method?
* 2 injections of PGF2a 11-14 days apart
* All cows will come into heat 5-7
days after the 2nd injection
* Better synchrony ⇒ 60% will respond to the 1st injection
30
Describe how the CIDR Estrus synch protocol works.
* CIDR ⇒ Progestrone
* Placed intra-vaginally for 7 d.
* Give a shot of PGF2a on d. 6
* Remove the CIDR on d. 7 ⇒ cows should come into estrus 1-3 d. after the CIDR is removed
31
Where does conception (fertilization) occur in?
Uterine Tube
| (Fallopian tube; Salpinx; Oviduct)
32
When is it appropriate to use the term "Embryo"?
* Used to describe the early non-distinguishable stage
* from fertilization ⇒ d. 42 of parturition
33
When is it appropriate to use the term "Fetus"?
* W/in the uterus, but the species is recognizable
* d. 42 ⇒ term
34
What is the specific pregancy protein produced by Bovine & Ovine embryos?
Interferon-T
| (INF-T)
35
What type of placentation do cows have?
* Synepithelial-chorial
* Cotyledonary
36
What is the main P4 source during bovine pregnancy?
CL
| (d. 5 - 150)
37
When is the placenta capable of producing enough P4?
What does this mean pracitcally (in regards to abortion)?
* d. 150 - d. 265
* During this period, you must use PGF2a & Corticosteroids to successfully terminate a pregnancy
38
When is appropriate to use the term EED?
(Early Embryonic Death)
If death occurs BEFORE d. 42 of gestation
39
What are the consequences of EED?
* BEFORE maternal recognition of pregancy ⇒ NO extension of the luteal phase
* AFTER maternal recognition of pregnancy ⇒ increased interestrus interval
40
What is the condition Arthrogryposis?
When the joints are permenantly flexed
41
What is the condition Schistosomus Reflexus?
* Failure of the body wall to close properly
* Abdominal organs are on the outside (calf is "inside-out")
42
Describe the condition of Hydro**allantois**.
(85-95% of cases)
* Due to abnormal placentation
* Excessive development of allantois fluid over 7-14 d. ⇒ rapid!!!
* \> 15 L & can be as high as 150 L
* **_C.S._**: Bilateral abdominal distention, dyspnea,
anorexia, dehydration, constipation,
rumen atony, recumbency & small fetus
* **_Prognosis_**: Poor ⇒ slaughter cow
43
Describe the condition of Hydro**amnios**.
| (5-15% of cases)
* Excessive amniotic fluid (\>5 L)
* Malformed fetus ⇒ doesn't swallow amnion
* **_C.S_**: slow accumulation of fluid
* **_Complications_**: RFM & metritis
* **_Prognosis_**: Good ⇒ don't use the same bull (fetal problem)
44
TX of hydro**allantois**?
Slaugther the dam
45
TX of Hydro**amnois**?
* Induction of parturition
* Draining/Modified C-section
* Fluid manangement & TX shock
46
List the possible complications of Hydro**allantois**.
* RFM
* Metritis
* Pre-pubic tendon rupture
* Shock
* Hernia
* Coxo-femoral dislocation
47
What is Fetal mummification?
* Fetal death w/ a _CLOSED_ cervix & a persistent CL
* fetus remains trapped *in utero* & get completely dehydrated
* Viral etiology
* Often occurs in the 2nd trimester
* Lack of O2
48
DX & TX for Fetal mummification?
* DX:
* Anestrus or prolonged gestation
* "Woody" fetus felt on rectal palpation
* TX: PGF2a
* Good prognosis; cow is not systemically ill
49
What is Fetal maceration?
* Regression of the CL ⇒ _OPEN_ cervix ⇒ Bacteria gain excess & attack fetus
* Foul smelling vaginal discharge
50
DX & TX for Fetal maceration?
* **DX**:
* Foul vaginal discharge
* Crepitant, bones felt on rectal palpation
* **TX**:
* Ineffective ⇒ Cull
51
Why are Vaginal Prolapses a problem?
TX?
* Are hereditary & often recur
* Cull the dam after calving
52
Vaginal prolapses always occur _______ calving & uterine prolapses always occur _______ calving.
* VP ⇒ before calving
* UP ⇒ after calving
53
List the possible causes of Prepubic Tendon Rupture.
What are the C.S.?
* **Etiology:**
* Multiple feti
* Hydrops (esp. hydroallantois
* **C.S**.:
* Loss of udder definition
* Saw horse stance
54
Why would you want to induce abortion &/or parturition?
* Unwanted pregnancy ⇒ heifer
* Avoid calf overgrowth (Belgian Blue)
* Prevent excessive udder edema
* Optimize pasture use
* Availablity of labor
* Terminal dz. in the dam
55
What hormone can you use to induce labor up to 150 d. of paturition?
PGF2a
56
What drugs do you use to induced labor in a cow that is between 150 - 250 d. of gestation?
Long-acting corticosteroid _+_ PGF2a
57
How do you induce parturition in a cow that is between 250-270 d. of gestation?
Long acting steroid followed 8 d. later by a short acting steroid or PGF2a
58
How do you induce labor in a dam that is _\>_ 275 d. of gestation?
_Any of the following_:
* PGF2a
* Short acting steroid
* Medium acting steroid
59
What are some disadvantages of inducing labor in cattle?
* Low birth weight
* RFM
* Poor colostrum production ⇒ calf is immunocompromised
60
List some ABNORMAL caliving related disorders.
* Uterine prolapse
* RFM
* Post-partum metritis
* Milk fever
* Mastitis
61
Describe a Uterine Prolapse.
* Invagination of the gravid horn through the vulva w/in 15 hrs. of calving
* TX as an emergency
* Usually doesn't recur
* Often associated w/ subclinical *hypo*calcemia
62
How do you TX a Uterine Prolapse?
* Wash it up ⇒ check it for tears ⇒ replace
* Epidural anesthesia to control pain while replacing
* Clenbuterol (Beta-2) ⇒ relaxes the uterus
* Sugar or oxytocin ⇒ helps reduce the size of the uterus
* Ca2+ borogluconate (for milk fever)
63
Define Retained Fetal Membrane (RFM).
Failure to expel fetal membranes by 12 hrs. post-partum
64
How do you TX RFM?
* wait 4 days (can be left up to 10 d.)
* ABXs ⇒ only if cow is ill
* Monitor TPR & milk production
* **Extend VWP 90 days.**
## Footnote
**(Forced removal is contraindicated)**
65
C/S & TX of Endometritis?
* Often are "repeat breeders" w/ insidious infertility
* generally difficult to DX b/c ususally is sub-clinical
* Will see milky ("Whites") vaginal discharge
* TX is controversial ⇒ Cephapirin (Metricure) or PGF2a if a CL is present
66
Definition of a Pyometra?
Purulent material w/in the uterus + CL + closed cervix
67
C/S of a Pyometra.
How do you TX it?
* **NO systemic illness**
* **Rectal palpation:**
* Large, thick-walled uterus
* CL present
* Fluid filled uterine horn
* **U/S:** fluid filled uterus
* **TX** = PGF2a (repeat)
68
What is Clinical Puerperal Metritis?
| (Toxic metritis)
* Occurs w/in 21 d. of calving
* Involves ALL layer of the uterus
* Systemic illness ⇒ decr. milk yield & signs of toxemia
* Fetid watery, red-brown uterine discharge
* _+_ Fever
* Enlarged thin-walled uterus
* _+_ RFM
69
Give examples of "At-risk" cows.
* Assisted/induced calvings
* RFM
* Metabolic diseases (i.e. Milk fever)
* Vaginal discharge
70
What is the only licensed IU product in Canada/EU/Australia?
Metricure
| (active ingredient is Cephapirin)
71
What is the best option for TXing uterine infections?
Prostaglandins + Metricure!
72
Which nerve is damaged in Maternal Obstetrical Paralysis?
How do you TX?
* Obturator nerve
* TX:
* Dexmethasone ***_OR_*** NSAIDs
* Hobbles
* Deep, soft bedding
* Nursing care
73
When has Failure of Passive Transfer occured in a calf?
Little to no colostrum is consumed in the first 24 hrs. of life
(Calf's GIT track can no longer absord immunoglobulins by _+_ 12-24 hrs)
74
What are the 4 **definitive** signs of Pregnancy?
_On rectal palpation, you feel_:
1. Fetus
2. Amnoitic vesicle
3. Fetal membrane slip
4. Placentomes (cotyledons/caruncles)
75
Which other signs are **suggestive** of pregnancy?
_On rectal palaption, you note_:
* Asymmetry
* Failure to retract the uterus
* Presence of a CL
* Fremitus (hypertrophy of middle uterine a.)
76
When can you palpate the amniotic vessicle?
d. 35- 60 of gestation
77
When can you feel the Fetal Membrane Slip?
_\>_ d. 34 of gestation
78
What are some indirect methods for determining if a cow is pregnant?
* P4 in milk or blood ⇒ 21-24 d.
* Pregnancy specific proteins ⇒ 24 d.
* Estrone sulphate ⇒ 105 d.
79
When is gender determination possible in bovines?
best at ~ 8 wks.
| (d. 55 - 90)
80
Why is Embryo Transfer used?
* Incr. # of progency from genetically superior dams
* International trade
* Freezing of embryos
* Continue breeding from infertile dams
* Dz. control
* Polo clubs & mare breeding
81
What is the criteria used for selecting donor cows for ET?
1. Regular heat cycles commencing at a young age
2. HX of no more than 2 breedings to conception
3. Previous calves were born @ ~ 365 d. intervals
4. No parturition difficultues or reproductive irregularities
5. No conformational or detectable genetic defects
82
Can cattle super-ovulate?
How many ovulations can they have?
* Yes
* Use FSH or eCG
* _\>_ 10 viable eggs per ovulation
* avgerage is 5 transferable embryos
83
When are bovine embryos recovered for E.T.?
5-7 d. after breeding ⇒ morula, blastocyst stage
84
How many cells are in a morula?
8-16 cell stage
85
Where must the donor & recipient be in their cycle for successful ET?
Donor & Recipient must be w/in 12-24 hrs of each other in their respective estrous cycle
86
What is used to remove viruses in ET?
Trypsin TX
87
How can semen be sexed in the cattle industry?
* Fluorescent staining ⇒ more DNA in X chromosomes
* Flow cytometry ⇒ sort based on weight difference
88
What is main problem with IVP derived calves?
Large calf syndrome
89
Which hormones are involved in bovine parturition?
* fetal corticoids ⇒ incre. 10-15 d. pre-partum
* P4 ⇒ Estrogen
90
Estrogen is produced by _______ & results in what?
* By cotyledons
* Luteolytic
* Oxytocin receptors
* Softening of the cervix
91
Where does Relaxin come from?
What does it do?
* CL/placenta
* softens cervix & relaxation of pelvic ligaments
92
Define abortion.
Expulsion of non-viable or dead fetus btwn d. 152-270 of gestation ***_OR_***
the fetus survives \< 24 hrs.
93
Do veneral dz's (Trich & Campy) typically cause EED or Abortion?
EED
94
How do bacteria typically cause abortion?
Due to placentitis ⇒ causes abortion
95
How do viruses typically cause abortion?
* Generally infect the fetus directly:
* Abortion
* Teratogenic
* Placenta is usually unaffected
96
What samples would you need to collect if working up an abortion case in cattle?
* Milk
* Blood from dam
* Fetal blood
* Fetal stomach contents
* Fetal organs
* Placenta (if available)
(Be careful ⇒ Lots are zoonotic)
97
List the top 5 commonly isolated organisms responsible for abortion.
1. *Trueperella pyogenes*
2. Bacillus spp.
3. Listeriosis
4. *E. coli*
5. Lepotspirosis
98
What is the major complaint of Campylobacteriosis?
Dramatic decreased in herd conception rates
99
How is *Brucella abortus* transmitted?
* Ingestion of aborted material or fetal membranes
* Uterine discharge from affected dam
* Milk
* Conjunctiva
100
When do abortions typically occur due to *B. abortus*?
\> 5 months of gestation
101
How do you DX Brucellosis?
* Direct culture
* IMH
102
*B. abortus* causes _____________ lesions on the placenta.
Morocan leather lesions
103
Which Brucellosis vax will not interact w/ serologic tests?
RB51 vaccine
104
Which Lepto species is the biggest problem in the U.S?
Which animal spreads it?
* *L. pomona*
* From pigs
105
When does abortion due to Lepto occur?
typically 7-9 months of gestation
| (can be at any stage)
106
When do abortions occur due to Listeriosis?
What does the placenta look like?
* Last trimester
* Yellow, gray necrotic foci on the cotyledons & fetus's liver
107
When does abortion due to IBR/IPV (BHV-1) occur?
\> 4 months of gestation
108
When will BVD cause EED?
Dam is infected \< 100 d. of gestation
109
When does BVD cause mummification, congenital defects _+_ abortion & **PI calves**?
Damn becomes infected **betwn d. 100- 150** of gestation
110
When will infection w/ BVD lead to no significant disease?
Dam is infected \> 150 d. of gestation
111
How is Trichomoniasis spread?
Venereal transmission
112
What is a mycotic cause of abortion?
Aspergillus
113
What will the placenta look like if mycotic abortion occured?
Gross leathery appearance
114
What are the 2 main reasons cows are culled?
Mastitis & subfertility
