ADSC 2010 1st Edition Lecture 31 Outline of Last Lecture I The Dairy Industry II Feedstuffs Utilized A Roughages 1 Pasture 2 Hay B Concentrates III Milk Dairy Production A Mammary Gland a Function b Udder Support c Udder Structures 1 Alveoli 2 Lobules 3 Lobes 4 Milk Ducts 5 Gland Cistern 6 Teat Cistern 7 Streak Canal 8 Teat Sphincter IV Milk Production Regulation A Mammary Development B Hormonal control of Lactation C Milk Letdown a Oxytocin b Milking Rate c Adrenaline V Milk Production Cycle A Parturition B Colostrum Production Outline of Current Lecture I Milk Production Cycle II III IV V A Milk Production B Rebreeding C End of Lactation D Dry Period Milk Composition Factors Affecting Milk Production A Breed B Size C Age D Length of Dry Period E Nutrition F Body Condition G Milking Frequency H Season I Disease J Management Mastitis Calf Management A Uses of Dairy Calves B Calf Management Current Lecture I Milk Production Cycle A Milk Production After parturition milk yield increases rapidly to a peak about 45 90days Dairy cows generally lactate 10 12 months Persistency degree of maintenance of lactation This month s production last month s production x 100 Normal persistency is about 85 90 Peak production in Holstein is about 70 80 lbs day 8 10 gallons Milk production of a cow Total number of milk produced in lactation adjusted to 305 days B Rebreeding Want to keep production cycle at one year avg in US is 13 13 5 months Average cow in US is rebred at 90 D post partum Can rebreed at 45 60D if uterus has involuted and is healthy C End of Lactation II III Usually around 305D D Dry Period 40 60D Need time in dry period or subsequent lactations will be less productive Need time to rest and repair mammary gland Need time for cow to replenish body tissues Milk Composition Colostrum Transitional Whole Item 1D 3D 5D Total Solids 23 9 14 1 13 6 Proteins 14 0 5 1 4 1 Casein 4 8 3 8 2 9 Immunoglobins 6 0 2 4 0 1 Fat 6 7 3 9 4 3 Lactose 2 7 4 4 4 7 Minerals 1 11 0 87 0 81 Factors Affecting Milk Production A Breed Holstein about 85 of US Dairy cattle B Size Larger cows make more milk ROT 10 x cow s weight C Age Heifers should be bred at 15 months to calve at 24 months Peak production 6 8 years Mature cows produce about 25 more milk than two year olds Average production life of Holstein 5 6 years D Length of Dry Period Production cycle should be kept on a 12 month interval E Nutrition Need concentrates to meet high energy requirements for milk production At peak production up to 60 of diet is concentrate 16 18 protein Roughage needed for milk fat Acetate milk fat F Body Condition During parturition a cow will secrete more calories into her milk than she consumes G Milking Frequency IV V Most common 2X 3X yield 15 2X 4X yield 5 3X H Season Milk production is slower in summer months due to intake and temperature I Disease J Management Milking procedure Complete milk out Use of bovine somatrotropin Rumensin Proper Sanitation Mastitis inflammation of udder Caused by microbial infection Streptococcus agalactiae Staphylococcus aureus Invasion through streak canal Impairs alveolar function Reduces milk yield Increases white cell count Can be horizontally transmitted through improper milking procedures sanitation Losses from mastitis in the billions of dollars Calf Management A Uses of Dairy Calves Replacement heifers Need to replace to 1 3 per year Breeding bulls Veal production Three months of age or 300 lbs Beef production B Calf Management Weight 80 100 lbs Allow calf to nurse for 12 24 hours colostrum Esophageal groove Calf converted to milk replaces up to 8 weeks 8 10 body weight Overfeeding results in scours number one cause of calf mortality 1 2 weeks old calf starter and high quality hay 16 20 protein Hay starts rumen functioning Wean at 2 3 months Feed calf starter 1 lb day Hay free choice Overfeeding can result in low milk production Fat in udder 10 months heifers can be on high quality forage alone Breed heifers at 15 months 750 900 lbs Calve and into production
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