Sequence of Major Events : Dairy Cattle Reproductive Cycle Calving Not Pregnant 283 d82 d Pregnant Lactation Cycle Calving 305 d lactation 60 d “Dry” Calving Milk lb/day Days Postpartum Lactation Curve Dry
90 lb birth Puberty ( lb) <--- < st Parturition lb < lbs Conception Sequence of Reproductive Events in Dairy Cattle Weaning Sequence to reach calving at 24 months
Parturition Parturition Relaxin causes relaxation of ligaments in pelvic region Cervix relaxes from tightly closed state during pregnancy Expulsion of fetus through vaginal passage
Calving Environment Calving Environment Clean, dry area Pasture environment, if applicable Close to center of activity to allow for observation Ability to milk a cow in calving area Method for lifting animal up
Dystocia Difficulty in calving Incidence is influenced by birth weight of calves, proper presentation of calf, sire of calf Affects risk of calf mortality Incidence in heifers calving for the first time is ~ 8-9% for Holsteins –Use of calving ease sires can reduce incidence in heifers
Postpartum Care of the Calf Ensure the calf is breathing Disinfect the navel with 7% iodine Identify the calf (ear tag, tattoo, other) Remove calf from cow –Minimizes risk of disease transfer –Decreases calf mortality and morbidity
COLOSTRUM First milk secretion produced by cow at calving “colostrum” for 1 d after calving “transition milk” at 2-3 d after calving * High in antibodies that protect young from invading microorganisms
Postpartum care of calf II Provide injections of vitamins as needed Feed Colostrum –2-3 quarts within 30 min – 1 h after birth –Another 2-3 quarts within first 12 h of life
Colostrum and milk composition Holstein Item1 st milking2 nd milkingMilk Total solids Fat Casein Lactose Minerals Immunoglobulins Vitamin A
IMMUNOGLOBULIN ABSORPTION Blood Vessel Gastro Intestinal Tract at Birth ---- Blood Vessel Gastro Intestinal Tract at 24 hours After Birth Globulin cannot pass through the intestinal wall unchanged
Colostrum Source Older Cows –First Lactation ~5.9 % Antibodies –Third Lactation ~ 8.2 % Antibodies Vaccinated Cows Healthy Cows –Johne’s Free –Bovine Leukosis Virus - Free
Feeding Calves Waste Milk vs. Milk Replacer –8 to 10 % of body weight –Depends on housing
Feeding calves Offer Quality Starter starting < 2 wks of age –Stimulate Rumen Development Offer Water Typically will not feed hay or silage until after weaning if complete starter is used
Development of the bovine stomachs Birth3-6 mosMaturity Rumen25%65%80% Reticulum5% Omasum10% 7-8% Abomasum60%20%7-8%
Other management practices Dehorn Remove extra teats Additional Identification –Written file with ID number, DOB, sire, dam, condition at birth Vaccinations
Calf Housing Individual Housing –Hutches –Cold Confinement –Warm barns Draft Free Proper Ventilation Dry Bedding
Immunity to disease Natural at birth –Inherited: species, racial/group, individual –Acquired in vitro Acquired –Natural, disease –Artificial Active – vaccine Passive - colostrum
Calfhood diseases Scours –Characteristics –Causes Bacteria - infectious Nutrition - noninfectious Respiratory diseases –Pneumonia Lung damage, death