Progress 09/01/02 to 08/31/06
Outputs
In the first experiment, ear biopsies were collected from 107 sets of Holstein twins from six Wisconsin dairies resulting in 40 opposite-sex twins, 29 same-sex male twins, and 38 same-sex female twins. To empirically determine the frequency of monozygous (MZ) twinning, DNA extracted from ear biopsies collected from the 67 same-sex twins was PCR amplified using primers for a minimum of five polymorphic microsatellite DNA markers. Of the 67 same-sex twins, 62 were classified as dizygous (DZ) and five MZ resulting in a MZ twinning frequency of 7.5% of same-sex twins and 4.7% of all twins. The estimated frequency of MZ twinning in this population of twin calves using Bonnier's equation was 39.5% of same-sex twins and 24.7% of all twins. We concluded that MZ twinning occurs infrequently in Holstein cattle and perhaps less frequently than that reported in studies using Bonnier's equation to estimate MZ twinning. In the second experiment, a data set of Holstein calving
records from January 1996 to September 2004 comprising 4,103 herds with 2,304,278 calving events representing 1,164,233 cows and 96,069 twin births was extracted from Minnesota DHIA archives. Overall, the reported twinning rate was 4.2%, and twinning increased with parity (1.2% for nulliparous vs. 5.8% for multiparous cows; and with time (3.4% in 1996 to 4.8% in 2004) with a parity by time interaction. Calf mortality was greater after twin births, with 28.2 % of twin calving events reporting 1 or both calves as dead, compared to 7.2 % for singleton births. Calf mortality for primiparous and multiparous cows was 5.0% after a single birth and 25.5% after twin births, whereas for nulliparous heifers, mortality was 10.4% for singleton and 38.0% for twins. We conclude that although specific factors cannot be implicated, the increase in twinning across time suggests a concurrent change in 1 or more causative factors associated with twinning during the 9-yr study period. Our objective for
the third experiment was to characterize pregnancy loss (PL) for cows diagnosed with twin (T) vs. singleton (S) fetuses on a commercial dairy farm comprising 1,100 lactating Holstein cows. A total of 468 S cows and 74 T cows were included in the final data set. Overall, PL was greater (P<0.01) for T (25.0%) vs. S (4.9%) cows. Among T cows, only 5 had 1 CL, and 3 of these cows lost 1 fetus and 1 lost both fetuses. For T cows with 2 CL, 8.6% (6/69) lost 1 fetus and 13.0% (9/69) lost both fetuses. We conclude that PL is greater for T compared to S cows and that spontaneous loss of one fetus and maintenance of the other can and does occur for T cows. In the fourth and fifth experiments, we evaluated the interaction of pregnancy type [singleton (S) vs. twin (T)], and dry period feeding management [transition diet (NEL=1.54 Mcal/kg) for 3 (3TR) vs. 8 (8TR) wk before expected calving date (ECD)], multiparous (n=39) and primiparous (n=8) Holstein cows were used in a 2x2 factorial randomized
complete block design. Our hypothesis was that 8TR would improve metabolic status and lactation performance for T but not S cows. Contrary to our hypothesis, no interaction (P>0.05) of dry period feeding management and pregnancy type was detected either prepartum or postpartum; however, feeding a diet moderate in energy throughout the dry period was associated with increased milk production. Gestation length was shorter (P<0.05) for T than for S cows (276 vs. 281 d), and calf BW was greater (P<0.05) for twin vs. singleton calves (70.7 vs. 42.4 kg). More (P<0.05) T cows required calving assistance than S cows (70 vs. 30 %), and numerically more RP were recorded for T than for S cows (55 vs. 29 %). Although prepartum serum P4 (-7 to 1 d relative to calving) was greater (P<0.05) for T than for S cows (2.5 vs. 1.9 ng/mL), treatment did not affect average d to first PP ovulation (40-5 d), average d to first PP 10 mm follicle (15.0-1.8 d), diameter of the largest follicle at first PP
ultrasound (7.0-0.6 mm), or the incidence of anovulation (9.1%) or short luteal phases (11.4 %). We conclude that although T cows have a greater risk for calving assistance than S cows, no interaction of pregnancy type and dry period feeding management was detected for PP ovarian activity.
Impacts
Results from experiment 1 revealed that monozygous twinning occurs infrequently in Holstein cattle and perhaps less frequently than that reported in studies using Bonnier's equation to estimate MZ twinning. Thus, twinning in lactating Holstein cows primarily occurs as a result of two ovulations. Results from experiment 2 revealed that the increase in twinning across time suggests a concurrent change in 1 or more causative factors associated with twinning during the 9-yr study period. Thus, an increase in the incidence of multiple ovulation rate due to increased milk production across time may be causing the increase in twinning across time. Management of cows calving twins is a challenge for dairy producers that may increase in frequency across time. Results from experiment 3 revealed that pregnancy loss was greater for cows carrying twin fetuses and that spontaneous loss of one fetus can and does occur during twin pregnancies. These data refute the idea that cows
identified with twin pregnancies early in gestation be terminated. Results from experiments 4 and 5 provide basic physiologic knowledge regarding the metabolic and reproductive status of cows carrying twin vs. singleton fetuses. Our results do not support that feeding a high energy diet throughout the dry period would be a beneficial management strategy for cows carrying twin fetuses. Taken together, results from these experiments have extended and our knowledge of the basic and practical nature of twinning in dairy cattle.
Publications
- Silva del Rio, N., S. Stewart, P. Rapnicki, Y. M. Chang, and P. M. Fricke. 2007. An observational analysis of twin births, calf sex ratio, and calf mortality in Holstein dairy cattle. J. Dairy Sci. 90:1255-1264.
- Silva del Rio, N., B. W. Kirkpatrick, and P. M. Fricke. 2006. Observed frequency of monozygotic twinning in Holstein dairy cattle. Theriogenology 66:1292-1299.
- Silva del Rio, N., H. Lopez, R. R. Grummer, and P. M. Fricke. 2007. Effects of twin pregnancy and prepartum diet on postpartum ovarian activity in Holstein dairy cows. J. Dairy Sci. 90(Suppl. 1):533.
- Silva del Rio, N., J. D. Colloton, and P. M. Fricke. 2007. Pregnancy loss in lactating Holstein cows diagnosed with twin versus singleton fetuses. J. Dairy Sci. 90(Suppl. 1):533.
- Silva del Rio, N., R. R. Grummer, and P. M. Fricke. 2007. Effects of twin pregnancy and dry cow feeding strategy on milk production, energy balance and metabolic profiles in Holstein cows. J. Dairy Sci. 90(Suppl. 1):615.
- Silva del Rio, N., S. Stewart, P. Rapnicki, Y. M. Chang, and P. M. Fricke. 2005. An observational analysis of twin births, calf sex ratio, and calf mortality in Holstein dairy cattle. J. Dairy Sci. 88(Suppl. 1):298.
- Silva del Rio, N., B. W. Kirkpatrick, and P. M. Fricke. 2004. Observed frequency of monozygotic twinning in lactating Holstein cows. J. Dairy Sci. 87(Suppl. 1):65.
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Progress 01/01/05 to 12/31/05
Outputs
To assess twinning trends across time, a data set of calving records from January 1996 to September 2004 comprising 6,226 herds with 2,900,708 calving events was extracted from Minnesota Dairy Herd Improvement Association archives. Cows with parity greater than 7, herds with less than 100 total calving events, and herds reporting more than 10 percent of incomplete calving records at any year of the study were removed. The final analysis included 2,304,278 complete calving records from 4,103 herds representing 1,164,233 Holstein cows and 96,069 twin births. Twinning and mortality trends were analyzed using the Logistic Reg model of SAS including the main effects of calving season, parity (nulliparous heifers, P1; primiparous cows, P2; multiparous cows, P3+) and gender with year as a covariate and all two-way interactions included in the model. Overall twinning rate was 4.2%, increasing with parity (1.2% for nulliparous vs 5.8% for multiparous), and with time from 3.4%
in 1996 to 4.8% in the last 12 months of data collection (Oct-2003 to Sept-2004); however, there was a parity by time interaction with primiparous and multiparous cows increasing at a greater rate across time than nulliparous heifers. Independent of parity, the greatest twinning rate was observed when conception occurred from August to October compared with other seasons. Calf mortality was greater for nulliparous heifers than for primiparous and multiparous cows for both singleton and twin births with a reported mortality of 10.4 and 38.0% for nulliparous heifers, compared with 5.0 and 25.5% for primiparous and multiparous cows, respectively. Calf sex ratio (Male, M; Female, F) was 53.3% M, 46.7% F for singleton calves and 30.1% MM, 43.6% MF 26.3% FF for twin calves. Although specific factors cannot be implicated, the increase in twinning across time suggests a concurrent change in one or more causative factors associated with twinning during the 9-yr study period. Economic losses
from perinatal mortalities are important even among the small herds represented in this data set
Impacts
Although specific factors cannot be implicated regarding the causes of twinning in this data set, the increase in twinning across time suggests a concurrent change in one or more causative factors associated with twinning during the 9-yr study period. Even on the smaller farms represented in this data set, perinatal calf mortality was high, and twinning increased the incidence of perinatal calf mortality. Benchmarking of twinning, calf gender ratio, and neonatal death losses can help dairy managers to better understand the level of management on their dairies with resepect to the population of dairy farmers in the upper midwest.
Publications
- Silva del Rio, N., S. Stewart, P. Rapnicki, Y. M. Chang, and P. M. Fricke. 2005. An observational analysis of twin births, calf sex ratio, and calf mortality in Holstein dairy cattle. J. Dairy Sci. 88(Suppl. 1):298 (Abstr.)
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Progress 01/01/04 to 12/31/04
Outputs
The on-campus phase of this research is ongoing and is approximately 75% complete at this time. A field trial has been completed to assess the proportion of mono- vs. di-zygous twins in the Holstein population. Bonniers equation has been used to mathematically estimate the frequency of monozygotic twinning in epidemiologic studies of twinning in dairy cattle. Our objective was to empirically determine the frequency of monozygotic twinning in lactating Holstein cows and compare it with that predicted by Bonniers equation. Ear biopsies were collected from 107 pairs of Holstein twins from 6 Wisconsin dairies resulting in a sex ratio (Bull:Heifer) distribution of 40 B:H, 29 B:B, 38 H:H. The estimated frequency of monozygotic twinning in this sample based on Bonniers equation was 39.5% of same-sex twins and 24.7% of all twins. To empirically determine the frequency of monozygotic twinning, DNA was extracted from ear biopsies collected from same-sex twins (67/107 pairs) and
was PCR amplified using primers for nine polymorphic microsattelite markers. All mixed-sex twin pairs were classified as dizygous as well as same-sex twin pairs differing at least in one microsatellite marker. Same-sex twin pairs were classified as monozygotics when for 5 or more microsatellite markers were identical. Of the 67 same-sex twin pairs 62 were classified as dizygotic and 5 as monozygotic, resulting in a monozygotic twinning frequency of 7.5% of same-sex twin pairs and 4.9% of all twin pairs. Complete twinning data was collected throughout a 12-month period in two of the farms, representing a total of 1,212 calvings. Both farm and season affected twinning rate. We conclude that Bonniers equation overestimated the frequency of monozygotic twinning in this population of Holstein cows.
Impacts
Development of long-term management options and short-term production practices based on scientific research findings about well-being of dairy cattle carrying twin fetuses will immediately impact the efficiency and profitability of U.S. dairy farms.
Publications
- Silva Del Rio, N., B. W. Kirkpatrick, and P. M. Fricke. 2004. Observed frequency of monozygotic twinning in lactating Holstein cows. J. Dairy Sci. 87(Suppl. 1):65.
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Progress 01/01/03 to 12/31/03
Outputs
Twinning negatively affects the health and well-being of dairy cattle, thereby limiting efficiency and profitability of the dairy enterprise. At present, information on managing twinning in dairy cattle is inadequate, and development of a practical strategy to mitigate the negative effects of twinning is critical, especially if the trend toward increased twinning in dairy cattle continues. The purpose of this project is to develop a periparturient management strategy for cows carrying twin fetuses. Noelia Silva Del Rio (a M.S. student) initiated the nutritional aspect of this research trial in the spring of 2003. To date, half of the animals have been enrolled in the trial and one-third of the animals have calved. Hernando Lopez (a Ph.D. student) has initiated the reproductive aspect of this research trial. This research project is well underway; however, because of the 9-month interval between conception and calving, there are no results to report from the
nutritional or reproductive aspects of this project at this time.
Impacts
Development of long-term management options and short-term production practices based on scientific research findings about well-being of dairy cattle carrying twin fetuses will immediately impact the efficiency and profitability of U.S. dairy farms.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
This project was funded in September 2002. A graduate student was hired for this project in October 2002, and this student has started the embryo transfers to initiate twinning in a group of lactating dairy cows. Once established, cows carrying twin and singleton fetuses will be subjected to either a 3 or an 8 week transtion ration feeding period.
Impacts
Development of a practical and effective management strategy for dairy cattle carrying twin fetuses may immediately impact the efficiency and profitability of U.S. dairy farms by improving dairy cattle health and well-being.
Publications
- No publications reported this period
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