ANSC 280Heifer DevelopmentHeifer Development - Allowing a calf to suckle can cause infection in the utters (mastitis)- Rota corona vaccine: given to healthy and pregnant cows to prevent diarrhea in their calves due to rotavirus, coronavirus, and e coli. Drugs aren’t always needed, electrolytes and water can get a calf through anything - Colostrum: milky substance that is produced the first few days after giving birth before the true milk is produced. It contains proteins, carbohydrates, fats, vitamins, minerals, and antibodies that fight disease-causing agents such as bacteria and viruses. True colostrum is rich in the antibodies that protect the calf from diseases in early life, before its own immune system starts working. Colostrum is also important as the first source of nutrients after birth. Antibodies are proteins that identify and destroy disease-causing organisms, or pathogens, in the calf.o A calf should receive the first feeding of colostrum within 1 hour of birth and 10% of its body weight in total colostrum within 10 hours. A calve’s small intestines ability to absorb immunoglobulins declines rapidly in the first few hours of life. - A calf beyond 24 hours of age goes on milk replacement for about 3 months- Once the calf is beginning to be weaned, it needs to be on 2-6 lbs. of grain per day. - At about 3-4 months of age, the calf needs vaccinating because colostrum only lasts about 3 months. A general 7-way vaccine is usually sufficient. Begins protecting against respiratory illness. Calfhood vaccination must be done through a veterinarian*- The animal must be brought to puberty before it is bred.o Puberty is reached by fat weight, not ageo Body condition score. Want them to grow rapidly but not gain too much weighto Jersey cows reach puberty at about 9 monthso Holstein reach puberty at about 12 monthso Allow 1-3 cycles to occur before breeding due to fertility o Gestation for bovine- 280 days-9months o You want them to give birth around 24 months. So they need to be pregnant by 14 months, start trying around 13.5o Heifers are usually fertile and not hard to impregnateCow Development - Lactation causes stress in first lactation heiferso Negative energy balance- when an animal cannot consume enough calories to compensate for the milk they are putting out. It is measured in days of milk (40 DOM- 40days post calving). The negative energy balance should last about 21 days, if it is any longer the nutrition plan is off. Nutrition Basics - **TMR- total mixed ration- Corn silage- entire corn plant chopped up, an anaerobic environment is needed so you cover with plastic and allow it to ferment. Provides energy for milk production. Very few dairies don’t have this, and it is very cheap ($0.01/pound)- Free choice hay, grain is also provided- Some cows will only eat corn silage, and will get acidosis - Some only eat grain, and too much protein will harm the kidneys- Some only eat hay, and they aren’t getting the nutrition they need to produce milk - TMR is the mixture of corn silage, hay, and grain. It must be the perfect mix to get the cow to eat. This now outnumbers computer feeders.- Per cow per day, they eat about 110 lbso 70 lbs. corn silage-32% dry matter, often the wettest componento 24 lbs. of grain – 40% is corn or corn byproducts, and it is expensive. >90% dry mattero 15 lbs. wheat silage – 32% dry mattero 5.5 lbs. dry hay- 95-98% dry matter - The ideal intake of dry matter is 50% per day for optimum milk production. This is extremely difficult to achieve Reproduction - Pregnancy is needed for lactation and therefore makes the dairy industry go around - Lactation curve: peak lactation occurs at 75-95 days of milk - A negative energy balance is desired by 21 days of milk. But if it goes on too long, the cow wont peak - The voluntary waiting period is the amount of time that is waited before AI is done after the cowhas calved. The ideal timing is to wait to breed for 60 days. 42-60 days is moderately successful. - *The estrous cycle of a cow is 21 days- 282 days (gestation) + 60 days (VWP)= 342 days between calving - Dry period: 60 days prior to calving, stop milking the cow. This gives the mammary glands a break, and an opportunity to add fat reserves to the cow if needed. Decreasing the dry period is possible, but you cannot go less than 45 days. - **THREE REPRO technologies that have advanced in the dairy industry:o Artificial Insimination: better semen, genetic advancement, disease control, estrous detection required o Ultra-sound: gives us knowledge about the cycle, also allows us to check sooner for pregnancyo TAI: estrous detection not required, breed from a hormonal standpoint, more efficient than plain AI. Double Ovsynch is a 27 day protocol and is the most