PURDUE UNIVERSITY COOPERATIVE EXTENSION SERVICE WEST LAFAYETTE INDIANA 47907
Reproduction of Dairy Cattle: Normal Postpartum Physiology
M.E. Lech and R.D. Allrich, Department of Animal Sciences L.A. Horstman and C.J. Callahan, Department of Veterinary Clinical Sciences
The reproductive performance of the postpartum cow plays a large role in determining the reproductive success of the herd and therefore influences the production and profits of the entire dairy enterprise. The calving interval has long served the dairy producer as a measure of reproductive performance. The ideal calving interval for dairy cattle is 12 to 13 months. A 12- to 13-month interval ensures optimum milk production per cow.
A lengthened calving interval causes an overall decrease in milk production because it allows for excessive udder involution between calvings. It also increases the overall feed and housing costs needed to maintain the cow. In addition, cows with extended calving intervals become excessively fat, and this leads to the fat cow syndrome. Cows affected by fat cow syndrome have increased incidences of ketosis, milk fever, and retained placenta. A shortened calving interval, one of less than 12 months (with a short dry period), does not allow for the necessary repair and rebuilding of the glandular tissue in the udder.
Management factors have an important influence on the reproductive efficiency of the postpartum cow. An organized and systematic approach to reproductive management of the postpartum cow is essential. Accurate and complete recordkeeping is the first step to increasing the herd’s reproductive performance. Up-to-date records not only provide the producer with valuable information for use in troubleshooting reproductive problems, but they also show important trends and progress in finances, individual animal and herd production, and genetic improvement.
An important management-related problem facing dairy producers today is faulty heat detec-
tion. For information on improving heat detection see Purdue Extension Publication AS-453, “Improving the Detection of Estrus in Dairy Cattle.” Another management-related problem the dairy producer may experience is improper artificial insemination timing or technique.
Nutrition also plays an important role in the postpartum reproductive performance of dairy cattle. The most important nutritional factor is the overall energy balance of the animal. Both feed intake and body tissue reserves are used as energy for body functions and milk production. The requirements for energy of a cow in early lactation exceed her intake of energy, and therefore she depletes her body of energy stores. Depletion of energy stores causes the weight loss commonly observed during the first 8 weeks after calving. Feed intake increases slowly after calving and may not peak until 80 to 120 days postpartum; therefore, it is very important to feed a balanced, palatable ration to both stimulate appetite and deliver the necessary energy required at this time.
This publication describes the normal functions of the cow’s reproductive system during and after calving. A companion publication, Purdue Extension Publication AS-456, "Reproduction of Dairy Cattle: Postpartum Disorders,” discusses abnormal conditions of the cow’s reproductive system during and after calving.
Parturition (Calving)
When parturition begins, the cow will appear restless and will frequently lay down and get back up. At this early stage, the uterus begins contracting to move the calf into proper position and to enlarge the opening of the cervix. As parturition
This publication was made possible in part by the Indiana State Dairy Association.
animal sciences dairy
AS-455