MATERI 10 LAKTASI DAN PUERPUREUM MK. ILMU REPRODUKSI Lab. Reproduksi Ternak Fapet UB 1
SUB POKOK BAHASAN Proses laktasi (Mekanisme Let down susu) Peranan Laktasi bagi Reproduksi Proses Pengembalian organ reproduksi post partum Peran hormon prolaktin pada pembentukan susu dan pengaruhnya terhadap an estrus serta pengaruh oxytosin terharap letdown susu Lab. Reproduksi Ternak Fapet UB 2
Anatomy of the Mammary Gland Lobule which contains Alveoli COW Lobe Alveoli Synthesis of Milk Primary and Secondary Ducts (Non-secretory) Cow: 4 Glands 1 gland/teat Ewe & Doe: 2 Glands 1 gland/teat Teat Cistern Gland Cistern Storage area 100-400 g of Milk Redrawn from Bearden, H.J. and Fuquay, J.W. (1997) Applied Animal Reproduction Teat Meatus Opening
Suspension of the Mammary Gland Lateral Suspensory Ligament Medial Suspensory Ligament From Swett et al. 1942. J. Agric Res. 65:19-42
Anatomy of the Mammary Gland COW Alveolia Gland Cistern Teat Cistern From Swett et al. 1942. J. Agric Res. 65:19-42
Mammary Gland of Sow and Mare Teat Cistern Streak Canal Gland Cistern Sow: 10-14 teats 2 glands/teat Mare: 2 teats 2 glands/teat
Alveoli Bloodflow is very important Brings substrates for milk production 500 liters of blood needed to produce 1 liter of milk Arteriole Venuole Myoepithelium Capillary Duct Lumen Epithelial Cells Synthesize milk Oxytocin stimulates contraction Redrawn from Bearden, H.J. and Fuquay, J.W. (1997) Applied Animal Reproduction Passage of milk to gland cistern
Comparison of Colostrum to True Milk Approximate composition of colostrum and normal Holstein milk First-Milk 2nd and 3rd Day Colostrum Colostrum Milk Constituent (percent) (percent) (percent) Fat 6.0 3.5 3.5 Nonfat solids 22.3 Decrease 12.5 8.8 Protein with 18.8 time 7.5 3.25 Immune globulins 13.1 1.0 0.09 Decrease Lactose with 2.5 time 4.0 4.60
Calf can absorb immunoglobulins with decreasing efficiency up to 24 hours after birth Antibodies - absorption in gut decreases with time especially after gut is stimulated. Example: Milk given without colostrum will stimulate gut closure for absorption of immunglobulins Immunoglobins in calf are as high as dam within a few hours Calf's immune system not functional until 1-2 months postpartum Colostrum provides passive immunity Need to give newborn calf at 5% of body wt in colostrum Foal may also need extra colostrum - Check IgG in blood 18-36 hrs from foaling Test IgG Blood Levels Failure of immune transfer < 400 mg/dl Partial transfer 400-800 mg/dl Normal > 800 mg/dl Treatment if deficient: Colostrum from other mares Infuse serum or plasma IgG i.v.
True Milk Production: 500-1000 liters of blood pass through gland to produce 1 liter of milk. Blood precursors of the milk constituents in the ruminant Milk constituent Blood Precursor Water Water Lactose Glucose Protein Casein Amino Acids ß-Lactoglobulin Amino Acids -lactalbumin Amino Acids Milk serum albumin Blood serum albumin Immune globulins Immune globulins Fat Fatty acids Acetate, ß-hydroxybutyrate, blood lipids Glycerol Glucose, Glycerol from triglycerides Minerals Minerals Vitamins Vitamins Unique to milk
Maintenance of Milk Production: Metabolic hormones involved Thyroxine & Triiodothyroine (Thyroid) Nutrition is also important Insulin and Insulin-like Growth Factor IGF-I Corticosteroids Growth hormone Note: Prolactin is important for first secretion of milk but may play only a minor role after the start of lactation Can utilize Bovine Somatotropin (BST) - Trade-name Posilac to increase milk production (5-15 lb/day). Growth Hormone stimulates IGF-I from liver which affects milk production. It increases metabolism of body fat stores and bloodflow to mammary gland. Dairy cows start at 63 days of lactation (9th week of lactation)
Need suckling stimulus + removal of milk oxytocin - milk let down Stimulates myoepithelial cells of alveolus As gland fills, pressure shuts off milk secretion Example: Milk a cow 2x vs. 3x/Day, Get a 15-20% in milk Fills usually within 6 hours production Problems with milk-let down: Fear or Stress Causes adrenalin which inhibits oxytocin release Response of myoepithelial cells to oxytocin Vasoconstricts - oxytocin supply to gland Milk 305 days - 60 days dry-off period. Allows time for tissue to regenerate itself. When wean calf gland fills stopping secretion by epithelium which degenerate and are absorbed. New cells develop under prolactin stimulation in late pregnancy