Teats/Mastitis

Question 1

No of glands/teats and streak canals in cows, sheep/goats, horses, SACs, camels

Answer 1

Cows - 4 glands, 4 teats, 1 streak canal per teat. All 4 quarters separated, no internal communication.

Mares - 2(4?) glands, 2 teats, 2 streak canals per teat

Sheep/goats - 2 glands, 2 teats, 1 streak canal per teat

SACs - 4 teats, 2 streak canals each

Camels - 4 teats, 3 streak canals each

Question 2

What is the main blood supply to the mammary gland

Answer 2

Comes primarily from EXTERNAL PUDENDAL

Branches of the external iliac (aortic bifurcation) - femoral aa & pudendoepigastric trunk = ext pudendal& caudal deep & superficial epigastric vv. Ext pudendal runs through inguinal canal & gives rise to cranial & caudal mammary branches.

Smaller contribution from mammary branch of ventral perineal aa (branch of internal pudendal from internal iliac)

Question 3

Surgical treatment options for chronic mastitis

Answer 3

1. Hemi-mastectomy or radical mastectomy (more commonly small ruminants) - elliptical skin incision, preserve skin for closure. Dissect down to abdominal wall and & remove ligating vv as encountered.
2. Chemical destruction - of the affected quarted when suspensory apparatus (suspensory lgament) still intact. Can use 100ml 10% formaldehyde in 500ml saline, 50-100ml 3% silver nitrate, 20ml 5% copper sulphate, 60ml CHx
3. Ext pudendal ligation - susp apparatus intact. Better in small rums (larger supply from ventral perineal vv in cows) - inguinal incision, ext pudendal vv are the only ones coursing thorough inguinal canals. Combine with teat amputation for drainage. Will eventually slough.

Question 4

Layers of the teat wall (from in to out)

Answer 4

• Internal - teat sinus
• 2 layer cuboidal epithelium
• submucosa
• connective tissue layer
• smooth muscle
• outer stratified squamous epithelium (skin)

Question 5

Where is the Rosette of Fursenberg?

Answer 5

Junction between the stratified squamous epithelium lining the streak canal & the 2 layer cuboidal epithelium lining the remainder of the teat. ie represents the proximal extent of the teat canal/streak canal

Question 6

What separates the teat sinus from the gland sinus in cattle?

Answer 6

Annular ring.

Question 7

Methods of local anaesthesia for teat surgery

Answer 7

1. 5ml lidocaine instilled into streak canal
2. 20ml lido injected circumferentially around base of the teat in region of anular ring, avoiding vv & teat & gland sinus

Question 8

Methods of supernumary teat removal

Answer 8

1. At 3-6mo old; cut off from cranial to caudal w scissors
2. >6mo - remove w emasculator (more profuse haem)
3. During gestation/lactation - elliptical incision around junction of prox/middle 1/3 of teat, transect teat wall more proximally. Can have clamp at bast to limit haem. Ligate any vv then oversew with clamp on. Then close subm & m & skin.
4. Conjoined teats - supernumart teats attached to side of 1ary teat & have accessory glands of varying volumes. Dissect elliptically parallel to the long axis of the teat. Dissect to its annular ring & transect at junct w teat & gland sinus. Close in 3 layers - subm, intermediate layer (smooth mm & CT), & skin. Use 4-0 PDS not penetrating mucosa.

Question 9

List of pathologies affecting milk flow

Answer 9

• Partial agenesis of streak canal -
• Tight streak canal - usually 2ary to trauma. Teat passively drained w canula 7-10. If this fails can cut sphincter with Hihgs teat knife, introduced straight & pulled out at 30-45° to spare streak canal, cutting Rosette area. Can repeat at 90-180° until get a fine passive stream of milk for >30secs after cut (indicates adequate flow)
• Obstruction of Rosette of Furstenberg - most common. Self inflicted or milk machine trauma. US for tissue flaps which can be resected blind (not recommended) or visualised w theloscopy. Can cut Rosette area as above also
• Milk stones - dx on palpation or US. Small stones can be ejected w hand milking. Otherwise crushed with small alligator forceps in teat cistern
• Obstructions in region of teat cistern or annular ring: Type 1 = <30% teat sinus mucosa involved, type 2 = >30%, type 3 = between teat & gland sinus, type 4 = extend from teat sinus to gland sinus. Need US to differentiate. Can tx w thelotomy or theloscopy

Question 10

Procedure for thelotomy

Answer 10

3-4cm longitudinal incision on lateral aspect of teat w prob inserted to prevent damage to medial wall. Remove any obstructing tissue at Rosett of Furstenburg. 2 layer closure - subm & intermediate layer w 3-0/4-0 monofilament. Then skin

Most (73%) will need streak canal cut within 1 week

68% return to normal lactation yield

Question 11

Indications & procedure for theloscopy

Answer 11

Main indication is removal of obstructive tissue within teat canal.

Only 15% require streak canal cut PO (vs 75% after thelotomy).

• Teat cannula through streak canal to insufflate with air w clamp at teat base
• lateral stab incision 10mm distal to teat clamp
• Introduce scope & use blunt probe through streak canal as instrument. Or can have separate instrument portal cranial or caudal for triangulation & removl of tissue w scissors.
• Portal closure in 2 layers - intermediate layer then skin
• 65% return to normal flow & 76% remain normal at next lactation
• Can return to milk machine milking 4d PO (vs 10d for thelotomy)