Reproductive management of dairy cows in the postpartum period

Achievement of an optimum calving to conception interval of 85 to 115 days requires concentrated management activities during the first 90 days follow ing calving, Early postpartum breeding In dairy cows results in more calves , and higher milk production per lactation, To achieve this goal, careful s urveillance at calving has to be assured Surveillance at calving has two ob jectives, One is to avoid the loss of the present calf by intervening early enough to save it but not so early to make things difficult for an as yet undilated dam, The other is to avoid trauma and infection of the tract, whi ch are more likely to occur in cows in which dystocia Is present for more t han four hours, Selection against families that encounter problems of mater nal-fetal disproportion and resultant dystocia are also important, Postnata l examination and treatment are recommended in all cows reported to have dy stocia or postparturient problems, such as retained placenta, milk fever, o r acetonemia, All these complications tan directly increase the intercalvin g period and should be recognised and treated as soon as possible, Accurate and early detection of pregnancy also plays a key role in achieving an opt imal calving to conception interval. Transrectal ultrasonography (7.5 MHz l inear-array transducer) was used to evaluate the accuracy of finding a corp us luteum on Day 20 or 21 or a conceptus on Day 29 or 30 after service, All of the cows with non-pregnancy diagnoses and having a corpus luteum were r eexamined on Day 33 or 34 after AI. The final ultrasound (US) examination w as made between Days 53 to 58 after service, Some non-pregnant cows (n=20) could already be recognised by the absence of a corpus luteum at the first US examination on Day 20 or 21 after AI and these cows might be treated at this early stage if needed (Table 1). The false negative US diagnoses (n=7) made on Day 29 or 30 after AI could be corrected on the basis of repeated US examinations 3 to 4 days later (Table 2), With the exception of one cow every non-pregnant cow was correctly diagnosed by Day 29 or 30 after AI and these cows might be treated at this stage if needed, Three to four US exam inations might contribute beneficially to the achievement of optimal calvin g to conception interval in field conditions. The simple monitoring of reproductive status and the intensive treatment of postparturient diseases will not of itself encourage greater reproductive efficiency, Cows should be challenge-fed during early lactation to minimise the negative energy balance, It appears that, cows in significant negative energy balance sustain damage to the developing population of follicles th at we recruited for ovulation 2 to 3 months later, The most favoured biolog ic treatment to restore oestrous cycling after parturition is the maintenan ce of good condition at calving and, the provision of a high-energy diet th at does not produce a fatty liver in early lactation.