ADSC 2010 Lecture 30Outline of Last Lecture I. Artificial InseminationA. Time for Breedinga. Cowb. Ewec. Sowd. MareII. Embryo TransferA. BenefitsB. LimitationsC. ProcessIII. Pregnancy DetectionA. CowB. EweC. SowD. MareOutline of Current Lecture I. The Dairy IndustryII. Feedstuffs UtilizedA. Roughages1. Pasture2. HayB. ConcentratesIII. Milk/Dairy ProductionA. Mammary Glanda. Functionb. Udder Supportc. Udder Structures1. Alveoli2. Lobules3. Lobes4. Milk Ducts5. Gland Cistern6. Teat Cistern7. Streak Canal8. Teat SphincterIV. Milk Production/RegulationA. Mammary DevelopmentB. Hormonal control of LactationC. Milk Letdowna. Oxytocinb. Milking Ratec. AdrenalineV. Milk Production CycleA. ParturitionB. Colostrum ProductionCurrent Lecture: I. The Dairy Industry- High Efficiency of “Nutrient” Utilization- Energy 17-25%- Protein 28-36%- High Investment Cost / Animal Unit- Cow cost- Feed cost- Facilities- Milking Parlor- Waste / Environment Management- High Income / Animal Unit- GA:o 16,500 # / cow / year x $.20 / # = $3,630 / cow / year- UGA:o 20,550 # / cow / year x $.20 / # = $4,521 / cow/ year- Chart: Profit in the Dairy Industry by Operation Size, 2011II. Feedstuffs UtilizedA. Roughages: about 4.5 tons / cow / year1. Pasture: silage (corn, sorghum, grass)2. Hay: cottonseed hullsB. Concentrates1. Corn2. Soy hulls3. Soybean meal4. Whole cottonseed5. By-Products:o Brewers graino Corn gluten feedo Animal proteino Citrus/beet pulpo Salad wasteIII. Milk/Dairy Production- Production / cow = increasing - Total pounds of milk:- 1950-1970: flat- 1970-now: increasingA. Mammary Glanda. Function: synthesize, store, secrete milk Cow has four functional glands (quarters) with no interchange of milk Rear quarters produce about 60% Fore quarters produce about 40%b. Udder Support1. Median suspensory ligament2. Lateral suspensory ligament3. Connective tissue** Inner mammary grove: between uddersc. Udder Structures1. Alveoli (basic secretory unit)o Millions of hollow, grape-like structures that produce and secrete milko Epithelial cells: milk producing cellso Myoepithelial Cells: smooth muscle cells that contract and cause milk secretion into the lumen of the alveolus o As the lumen fills with milk and expands, milk is forced intothe duct system of the mammary gland2. Lobules: groups of alveoli surrounded by a thin fibrous membrane3. Lobes: groups of lobules that drain into a single duct system4. Milk Ducts: ducts that drain lobes (about 30/duct)5. Gland Cistern (one / quarter):o Pocket formed at the openings of the milk ductso Short-term storage site6. Teat Cistern: cavity within teat7. Streak Canal: opening of teat to environment8. Teat Sphincter: smooth muscle closure around streak canalIV. Milk Production/RegulationA. Mammary Developmento Begins at pubertyo Estrogen involved in duct developmento Progesterone needed for alveolar-lobule developmentB. Hormonal control of Lactationo Prolactin stimulates/maintains milk secretiono Thyroxin, GH, and Adrenal Steroids are involved in maintenance of milk secretionC. Milk Letdowno Sensory stimulus (tactile, sight, sound, smell) produces nerve impulse to brain which causes oxytocin to releasea. Oxytocino Reaches udder 45-60 seconds following stimulationo Contraction of Myoepithelial cellso Pushes milk out/down into milk ductso Effect maintained about eight minutesb. Milking Rate : average cow about 5 minutesc. Adrenaline blocks oxytocin effectso Any factor prolonging milking reduces oxytocin effects and results in incomplete milk outo Incomplete milk out results in rapid decline in milk productionV. Milk Production CycleA. Parturition (Day 0)o Cow lactates in response to calvingB. Colostrum Production (Day 0-3)o First milk post-partumo High in immunoglobulin (proteins) that provide disease resistanceo Calf can absorb that protein about 24 hourso Calf removed after receiving colostrumo Calf survival rate 50-70% lower without colostrumo By 3-5 days post-partum, milk is acceptable for human
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