Economics of Twin Pregnancies in Dairy Cattle

Abstract

Twinning in Holstein dairy cows has increased over time concurrent with increased milk production. Twinning in dairy cattle is not desirable due to the negative effects on both cows that calve twins and calves born as twins that result in economic losses to dairy farms. Although a twin pregnancy could bring additional income from extra calves and shorten gestation length, twinning compromises milk production, increases the incidence of dystocia and perinatal mortality, decreases calf birth weight, increases the incidence of metabolic diseases, decreases fertility, increases the incidence of freemartinism, increases overall culling risks, and shortens the productive lifespan of cows. Based on a summary of economic analyses from several studies, the estimated losses due to twinning range between $59 to $161 per twin pregnancy. Most twinning in dairy cows is dizygotic and directly related to the incidence of double ovulations, and economic losses are greater for unilateral than for bilateral twins. Hormonal manipulation before artificial insemination that allows for timed artificial insemination is a primary strategy for decreasing twinning in dairy cows before it occurs by decreasing the incidence of double ovulation thereby decreasing conception of dizygotic twins and the associated negative economic consequences. When twins are diagnosed early during gestation, management options might include doing nothing, terminating the pregnancy, or attempting manual embryo reduction. Based on a recent economic analysis of these options, attempting manual embryo reduction decreased the economic losses of a twin pregnancy by $23 to $45.

Keywords: dairy cows; economics; twinning.

Figure 1

Trend in reported twinning rate in Holstein cows in the USA. from 1983 to 2003. Data includes nonlactating and lactating Holsteins. Open bars: data adapted from [6]; Solid bars: data adapted from [7].

Figure 2

Net cost of a twin pregnancy after three management strategies compared with a singleton pregnancy conceived at the same days after calving (DIM) for unilateral (a) and bilateral (b) twin pregnancies in second lactation. Source: Adapted from [24].

Figure 3

Net cost of different management strategies with respect to a single pregnancy, net profit of embryo reduction to do nothing for different scenarios for cows diagnosed with a bilateral twin pregnancy at 150 DIM. Scenarios: (1) baseline scenario when cow and herd average produce 9979 kg/year, milk price at $0.36/kg, conception rate at first resynchronization (CR) after pregnancy loss 35%, 21-d pregnancy rate after resynchronization (21d PR) after pregnancy loss 25%, days of gestation when twin pregnant cow lose gestation (DG) after do nothing strategy 75 d; (2) cow yielding 454 kg more than the baseline; (3) cow and herd average yielding 454 kg more than the baseline; (4) milk price increased by $0.05/kg milk; (5) CR and 21d PR reduced 5%; and, (6) DG at 52 d. Source: Adapted from [24].