Lactation

1. Lactation Dr. N. Matthew Ellinwood, D.V.M., Ph.D. February 3, 2014 Iowa State University College of Agriculture and Life Sciences

2. Final Exam • Format • Essay/short answer component • 3 at 15 points each • Answer one of the two following questions . . . • 45 multiple choice/T or F question • To encompass material through: • Thursday Feb 6, 2013

3. Lactation • Defining characteristic of mammals • Warm blooded vertebrates • Haired skin • Bearing of live young (usually) • Nursing young http://farm1.static.flickr.com/172/432172524_2941869cde.jpg?v=0

4. Anatomy • Multiple paired teats • Dog – 10 • Cat – 8 • Variation (can have 8-12) • Blood and lymphatic supply • Can affect spread of disease • Mastitis and cancer • Mastitis- rare, but serious cases occur • Cancer- common and preventable www.acvs.org

5. Anatomy continued • Parenchyma of the mammary gland • Secretory, ductal, and connective tissue • Teat sinus • Smaller than in cattle • Teat canal • Less than half the length of the teat • Teat openings • Multiple openings per teat • Dog ~ 10 • Cat ~ 5 http://en.wikibooks.org/wiki/Anatomy_and_Physiology_of_Animals/Reproductive_System

6. Mammary Gland Development • No significant mammary tissue during anestrus • Second half of pregnancy (and late pseudopregnancy) sees the development mammary glands to support nursing young • Endocrine dynamics peak at parturition to support lactogenesis • Declining progesterone • Increasing estrogen, prolactin, growth hormone, and glucocorticoids

7. Maintenance of Lactation:Galactopoesis • Balancing act • Hormonal support • Prolactin and other hormones • Physical emptying

8. Milk Ejection • Milk let down versus milk secretion • Smooth muscle cells versus secretory epithelia • Neuroendocrine reflex arc • Stimulation of the nursing pup sends afferent nerve impulses to the hypothalamus • Oxytocin secreting neurons in hypothalamus • Axonal release of oxytocin in pituitary • Posterior pitutary/neurohypophesis • Oxytocin transport through blood stream • Smooth muscle contractions lead to milk ejection

9. Colostrum • First milk • On average higher concentration of protein, minerals (not all), vitamins, and fats • Immunoglobulins (antibodies) • No transplacental transfer of maternal antibodies • Pups and kittens absorb across gut wall in the first 24 hours. • Gut wall closure- A continual process after birth • Influence of environment • Cold body temperature speeds closure • Feline isoerytholysis

10. Feline Neonatal Isoerythrolysis • AB blood group in cats • Types A, B, or AB • A dominant inheritance to B • AB type inherited separately • Alloantibodies • B cats have strong anti-A antibodies • A cats have week anti-B antibodies • AB cats have no alloantibodies • B queens bred to A toms • A kittens will absorb strong anti-A antibodies • Leads to life threatening complications • Remove kittens for first 48 hours and return to queen http://www.fabcats.org/owners/blood_groups/info.html

11. http://www.fabcats.org/owners/blood_groups/info.html

12. Pseudopregnancy Associated Galactorrhea in the Bitch • Abnormal milk production • Later stages of overt pseudopregnancy • Primarily a nuisance issue • Will reoccur in predisposed bitches • Poor management can lead to persistence • Proper management can limit • Anti-prolactin pharmacological therapy

13. Agalactia • Failure in mammary development during pregnancy • Mammaries of the bitch (usually, but also queen) appear grossly underdeveloped • Fostering pups or hand rearing

14. Failure of milk letdown • Hours to a few days until lactation commences • Tincture of time • Drug therapy

15. Milk Composition • Higher protein and fat content than other domestic species (2-3 x higher) • Lower sugar content • Queen slightly higher than bitch in fat and protein • Fat • 9.5-10.8% versus 3.7- 8.3% (cow and sow) • Protein • 7.5 – 10.6% versus 3.2 - 5.6% (cow and sow) • Sugar • 3.8 – 3.7% versus 4.6 – 5.0% (cow and sow)

16. Peak Lactation • 2-3 weeks post-partum • Greatest metabolic demand seen in dogs • Pups are growing by ~ 50% week during this period • Greater than adequate palatable food designed for growth and lactation • Small breeds particularly at risk during this period • Canine eclampsia

17. Eclampsia • Hypocalcemia or Puerperal Tetany • Life threatening decline in blood calcium levels • Small breeds, large litters, peak lactation and metabolic demands • Veterinary Emergency • Seizures and tremors may occur, resulting in a dangerously high temperature • Treatments • IV catheter to slowly and carefully deliver calcium and dextrose • Prevention • High quality growth and lactation diet

18. Mastitis • Infected mammary gland • Severity can vary from mild to life threatening • Adopt good standards of husbandry • Daily examination of each mammary and assessment of milk quality http://www.familyvet.com/Dogs/622.JPG http://www.dogbreedinfo.com/images19/MastitisCOMOXSassy285.jpg

19. Weaning • Weaning period is 6 – 8 weeks • Spontaneous versus induced • Variability in maternal behavior • Can be assisted by • Limiting food and water (carefully) • Limiting frequency of nursing • Limiting number of pups • Excluding access to pups http://www.laurdankennels.com/images/puppies_feeder.jpg

20. Review • Health and management issues during lactation • Periparturient period/late pseudopregnancy • Neonatal Isoerythrolysis • Agalactia • Galactorrhea • Peak lactation • Eclampsia • Entire lactation period • Mastitis