Effects of twinning and length of dry period on reproductive performance and cow productivity

Data of Holstein dairy cows in a private farm in Cairo Governorate comprising 522 calving events (22 for twins and 500 for singles) in the period from December 2009 to December 2010) were used to determine the effect of twinning and length of dry period (DP) on reproductive performance and production of dairy cows. During the study period, there were 22 twin births in a rate of 4.4%. All cows giving twins had shorter (p<0.05) gestation periods than cows giving singles. The level of dystocia associated with a twin birth is significantly greater than for a single birth (P <0.05). Survival at birth was greater for single and twin birth at a 90-day DP than for twin-born calves at a 60-day DP (P<0.05). In addition, the total weight of the calves born is significantly higher for a cow giving twin than single one and also significantly higher for a cow twin birth on a 90-day DP compared to a cow twin birth on a 60-day DP (P<0.05). In post partum period, Cow that had a twin birth had an increased chance of having a retained placenta compared to a cow that produced a single calf (p<0.05) and twin calving cows at 90-day DP (p< 0.05). A cow that had a twin birth on a 60-day DP had an increased chance of having metritis and/or endometritis after calving and more days to estrus, lower conception rates and more days to pregnancy than cows birthing singles and cow birthing twins at 90-day DP (P<0.05). There were significant differences (p<0.05) between twin groups and single-producing cows daily milk yields and total milk on postpartum (100 DIM). Form the present study, it concluded that Identification of cows gestating twins to provide for their lengthening of the drying off period and calving assistance at parturition is necessary to make twinning in cattle an economically viable technology.