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