THE ECONOMICS OF NATURALLY-OCCURRING TWINNING IN DAIRY-CATTLE

To determine the additional costs and returns of twin calvings in dairy cattle, an economic model was developed on the personal computer. Data used in the model were recorded on 33 farms over 6.5 yr and included 381 twin calvings. For missing information, assumptions were made from the literature. Additional calf returns turned out to be $2.96. Total additional cost were $71.47, consisting of $100.92 for milk reduction, $39.51 for increased premature culling, $19.25 for increased occurrence of abortion, $5.69 for increased therapy, and $6.09 for increased calving interval. Total losses were on average $171.47 - $62.69 = $108.51 per twin birth. Realistic changes in input variables could not change this negative outcome to a positive result. Therefore, it was concluded that it is not profitable to select to increase the number of twins in dairy cattle.