1. Lactation Physiology Mammary Gland

2. Prevention
Healthy cows with good immune systems will be able to fight off mastitis infections. Many mastitis pathogens are eliminated by the cow's own defense system.
Assure that the diets are balanced for Vitamin E and Selenium.
Immunization with J5 vaccine will not prevent infection but will decrease the severity of clinical signs.

3. The mammary gland nourishes the neonate
Exocrine gland; common to all mammals
Function: nourish the neonate
Food source: fat, protein, sugar (CHO), vitamins, minerals, water
Protection: immunoglobulins (first Ab protection; absorbed via intestinal tract)

4. The mammary gland is part the reproductive system
The mammary gland is loosely considered part of the reproductive system:
Serves a “reproductive function”; nourishment of the neonate = survival of species.
Relies on same endocrine (hormonal) support for development and function.
Example: gonadal steroids, prolactin, etc.

5. Endocrine Glands Affect Mammary Function

6. Mammary Gland Structure
Udder consists of four separate glands
A teat hangs from each quarter
Bottom of teat closed by sphincter muscle known as streak canal
Can have extra nonfunctional teats
Called supernumerary teats
Removed when calf is young

7. Mammary Gland Structure
Conformation of teats
Vary in shape from cylindrical to conical
Rear teats are usually shorter
Each teat has one streak canal
Teats should be moderately sized and located centrally on each quarter
Sphincter in each teat should be tight enough to prevent leakage
Teats are hairless

8. Mammary Gland Structure
Support system = Stroma (connective tissue)
Glandular; secreting tissue = Parenchyma
Alveoli- secreting epithelial cells
Duct system- lined by epithelial cells
Lobules & lobes- clusters of alveolar tissue supported by connective tissue

9. Separate Mammary Glands-Quarters
40%
60%
Front quarter is smaller

10. Mammary Gland Structure/Suspension
Intermammary groove separates left and right halves of the udder
Udder can weigh anywhere from 7 to 165 pounds
May support up to 80 pounds of milk
Rear quarters secrete 60% of the milk
Udder continues to grow in size until cow is 6 years of age
Well attached udder fits snugly against the abdominal wall in front and on the sides
Extends high between thighs in rear
3 major supporting structures
Skin
Median suspensory ligament
Lateral suspensory ligament

11. Mammary Gland Suspension
Skin
Minor role in support
Median suspensory ligament
Separates right and left halves of udder
Connects udder to abdominal wall
Lamellae
Elastic tissue which responds to weight of milk in udder
Lateral suspensory ligament
Inflexible
Surround the outer wall of udder
Attached to prepubic and subpubic tendons
Intermammary groove formed where lateral suspensory ligament and median suspensory ligament meets

13. Fig An illustrated view of the ligaments that permit udder suspension (Courtesy of Iowa State University)

14. Mammary Gland Support
Medial suspensory
ligament

15. Internal Anatomy Streak canal Teat cistern Gland cistern
Functions to keep milk in udder and bacteria out of udder
Teat cistern
Duct in teat with capacity of milliliters
Separated from streak canal by folds of tissue called Furstenberg’s rosettes
Gland cistern
Separated from teat cistern by the cricoid fold
Holds up to 400 milliliters of milk
Collecting area for the mammary ducts
From this branches the mammary ducts

16. Fig A dissected mammary gland showing the gland cistern, teat cistern and streak canal (Courtesy of Mark Kirkpatrick)

17. Alveoli and Duct System
Alveoli is the basic milk producing unit
Small bulb-shaped structure with hollow center
Lined with epithelial cells that secrete milk
Each cubic inch of udder tissue contains 1 million alveoli
Each alveoli surrounded by network of capillaries and myoepithelial cell
Contraction of myoepithelial cell stimulates milk ejection
Groups of alveoli empty into a duct forming a unit called a lobule
Several lobules create a lobe
Ducts of lobe empty into a galatophore, which empties into the gland cistern
Ducts provide storage area for milk and a means for transporting it outside
Lined by two layers of epithelium

18. Alveoli and Duct System

19. Alveolar Products Alveolus:
basic secretory unit; lined by epithelial cells which synthesize and/or secrete:
lipid - triglycerides & free fatty acids (FFA)
protein - caseins
lactose - disaccharide; osmoreactive molecule (draws water)
minerals & vitamins - Ca, P, K; Vits. A, B, C, D
water

21. Circulation
One gallon of milk requires 400 gallons of blood being passed through udder
Ratio may increase in low producing cows
Blood enters the udder through external pudic arteries
Blood exiting udder from veins at the base of udder blood can travel through two routes
Via external pudic veins
Via subcutaneous abdominal veins

22. Fig Blood flow to and from the mammary gland determines milk producing capability of the cow (Courtesy of Iowa State University)

23. Mammary Venous Circle
Cranial Mammary
Vein

24. Mammary Vessels

26. Mammary gland defense system
Smooth muscle sphincter surrounding the teat canal inhibits bacterial closure. Because the teat canal lumen remains dilated for up to 2 hours after milking, feed cows after milking to keep them on their feet.
Keratin, a waxy substance derived from the teat canal lining partially occludes the lumen of the teat canal and inhibits bacterial penetration. Only infuse the tip of intramammary infusion cannulas into the teat canal.
Somatic Cells are the most important natural defense mechanism to infection. Leukocytes (mostly PMN, polymorphonuclear neutrophils) function by phagocytosing and killing bacteria. They may reach in the millions.
Antibodies and other soluble factors in milk. They coat bacteria and enhance PMN engulfment. They also interfere with bacterial adhesion to tissues, reducing multiplication and neutralizing toxins.

27. Lymphatic System
Helps regulate proper fluid balance within udder and combat infection
Fluid drained from tissue only travels away from udder
Blood capillary pressure
Contraction of muscles surrounding the lymph vessels
Valves that prevent backflow of lymph
Mechanical action of breathing
Lymph travels from udder to the thoracic duct and empties into blood system
Flow rates of lymph depend on physiological status of the cow

28. Lymphatic System
Fluid enters the lymph system through open-ended vessels called lacteals

29. Function of the Lymphatic System

30. Lymphatic System- Edema
low pressure, passive system fed by a high pressure vascular system!
this situation results in pooling of interstitial fluid if evacuation of lymph is impaired
Example: tissue trauma; increased mammary blood flow at parturition

31. Alleviating Mammary Edema
Preparturient milking may be helpful
store colostrum from healthy cows to feed calves
Frequent milkout to reduce mammary pressure
Diuretics, corticoids to reduce swelling
Mammary massage, icing
work fluid towards supramammary lymph nodes
Reduce salt intake
Don’t feed too much, too early before calving

32. Foul smell and necrotic odor
Arcanobacterium pyogenes
(another)anaerobe
Watery milk, swollen udder
Coliforms
Watery and red, sick cow
Staph aureus: poor prognosis
Subclinical mastitis: contagious organisms:Staphylococcus aureus,
Streptococcus agalactia, Mycoplasma bovis
Clinical mastitis:
Environmental organisms: Strep. nonag. Group:50%
Coliform organisms (Eschericia coli, Klebsiella, Enterobacter sp., etc.)
90% of the time

33. Cow’s Reproductive Cycle
Follicles and
New Corpus
Luteum
Reproductive
Tract
Mature Corpus
Luteum

35. Uterus

36. Reproductive hormones
Estrogen: positive feedback
Progesterone:: negative feedback

37. Reproductive Physiology

38. Day 0 is considered to be estrus.
Days 1-5 are metestrus.
Days 6-17 are diestrus.
Days are proestrus.

39. Metestrus

42. Ovaries

43. Insemination Timeline

44. KaMar/ Bovine Beacon

45. Tail Paint

46. Tail Paint

47. Heat Watch ~1/2 mile range Receiver )))))))))))))))))))))))))))))))))
1. Transmitter with pressure
sensitive button on top
)))))))))))))))))))))))))))))))))
2. Mounted onto cow’s rump
using a patch and adhesive
3. The receiver accepts the mounting
activity signal from the transmitter
Receiver
4. Information is transferred to
computer for processing by
HeatWatch software.
~1/2 mile range

48. Ovsynch Ovsynch uses two hormones PGF2α and GnRH
Ovsynch occurs in three stages
Day 0 - Stage 1: GnRH injection to create a new follicle
Day 7 - Stage 2: PGF2α injection to end the currnet estrus cycle and regress the corpus luteum
Day 9 – Stage 3: Second GnRH injection to cause the new follicle to ovulate and release the egg
All cows will ovulate hours after the second GnRH injection
Day 10 – Insemination

49. CIDR - Source: ansci.wisc.edu
CIDRs (Controlled Internal Drug Release) are an intravaginal progesterone insert used in the beef cattle, dairy cattle, goat and sheep industries.
The progesterone is released at a controlled rate into the bloodstream after insertion.
In all species, CIDRs are used for the synchronization of estrus.
This can be highly beneficial in large herds because with the synchronization of estrus, groups of cows and heifers can be bred at the same time in a narrow window.  

51. Lutalyse Lutalyse is a veterinary pharmaceutical brand name
Lutalyse is a PGF2α therapy treatment
If an animal is known to be open (i.e. her ovulated egg was not inseminated), a shot of Lutalyse will end the cycle and start a new one.
Lutalyse/ PGF2α will cause the death of the corpus luteum, resulting in reduced progesterone production.
Pregnant women SHOULD NOT administer shots of Lutalyse; it can cause their bodies to terminate the pregnancy!

52. Rectal Pregnancy US: 40 day pregnancy Easiest, fastest, cheapest
status days post breeding
US: 12 days (18 days in small ruminants)
Radiograph: 90 days
Positive signs of pregnancy
Fetus
cotyledons/caruncles
amniotic vesicle
fetal membrane slip
Suggestive signs
Ipsilateral corpus luteum
Ipsilateral middle uterine artery in the broad ligament
US: 40 day pregnancy

53. Fetal Membrane Slip (be gentle, as you can damage a pregnancy by rough palpation) 32 days thread 1 horn 45 small string 1horn 60 string 2 horns >70 large string

54. Pregnancy Placentomes cotyledon/caruncle unit)
You must rule out that you a not palpating an ovary by feeling at least 3.
The fetus descends out of reach from 3-7 months. You can first feel the fetus at days To estimate an aborted fetus they are: 2 months mouse 3 months rat 4 months small cat 5 months large cat 6 months beagle dog
75 days pea size 100 dime 115 nickel 125 quarter 150 half dollar > 150 variable

55. Gestation: Avg. 283 days
1 – 2 days before parturition: elevated tail head
Stage I: Preparatory stage
~ 6 hours
Inappetance, restlessness, kicking belly
Stage II: Delivery
30 min – 4 hours (Avg. 75 minutes)
Heifers take longer
Head diving posture
Stage III
Expel placenta
4 – 12 hours
KNOW pg 375: normal PE calf

56. Calf care Oxygen Temperature Umbilical cord and umbilicus Nutrition
fetal membranes and fluids
1st breath ~ 30 secs; 90 – 110 breaths/min
Temperature
Draft free, deep bedding, heat source
100 – 102 degrees F
Umbilical cord and umbilicus
Usually naturally or rupture
3% provodine iodine or chlorehexidine (1:4)
Nutrition
Stand: 1 – 4 hrs
Bond
Pass meconium: 1st feces in 24 hrs.
Colostrum: IgG, dairy 4L and beef 1-2 L
10 – 15% BW in first 12 – 24 hours, After 24 hrs IV plasma
Milk replacer: 5 – 6% BW . BID
PE: Table 17 -1

57. Dystocia Common cattle and sheep 1st time (primiparous) mums
1st calf heifer, fat, torsion,
milk fever (no contractions)
3 approaches
Mutation and traction
Obstetrical chains, calf jacks
Fetotomy: in cattle
C – section
Fetus too large, small pelvis, cervix does not dilate, vaginal prolapse, dead fetus, malformed fetus

58. Post partum problems Retained placenta
Prolapse vagina or uterus; "cast her wethers" and "lost her calf bed

59. References Slides courtesy of Dr. H.D. Tyler, Iowa State University
References: Dr. M. A. Barnes, Virginia Tech and Dairy Cattle Science. 4th Ed