Effects Of Dystocia Research Articles

Postnatal maternal behaviour expression depends on lambing difficulty in Merino ewes

Dystocia, a prolonged or non-progressive birth event, is the main contributor to lamb mortality in Australia and across the world. Dystocia can cause neonatal hypoxia, central nervous system (CNS) damage leading to increased risk of starvation, exposure and mismothering, and death. These prolonged birth events can also cause fatigue, injury and death in the ewe. Dystocia may interrupt the expression of maternal behaviour and the strength of the ewe-lamb bond, and consequently lamb survival. This study focused on the effect of dystocia on ewe behaviour in the 2 h post-lambing. A total of 18 ewes were chosen for continuous behaviour annotation and analysis (dystocic (n = 9) and eutocic (n = 9)) based on the quality of video recordings, length of stage 2 parturition and classification by a single experienced observer. Dystocic ewes showed significantly lower expression of maternal behaviours and a significantly greater expression of avoidance behaviours compared to eutocic ewes. Additionally, dystocic ewes performed fewer behaviours in total compared to eutocic ewes.Dystocia can significantly affect the quality and quantity of ewe maternal behaviour expression, leading to increased avoidance of the lamb, increased risk of maternal disinterest, and increased risk of death for the lamb. If dystocic events can be identified quickly and accurately, measures can be taken to ensure the ewe and lamb recover successfully.

The effect of dystocia on oxidative stress, colostral antibody/passive immune status, and blood gases in Damascus goats and their kids

The effect of dystocia on oxidative stress, colostral antibody/passive immune status, and blood gases in Damascus goats and their kids

The incidence of difficult calvings in the beef cattle in the Slovak Republic

Received: 2018-05-04 | Accepted: 2018-05-14 | Available online: 2018-11-26 https://doi.org/10.15414/afz.2018.21.04.135-137 Calving difficulty is one of important economic traits in beef production. In the Slovak Republic calving difficulty in beef cattle is recorded on the regular basis, however, these data have not been used so far in decision making. The aim of this study was to get the first insight into the data. Data on 288 346 calvings in 5 major Slovak populations (Charolais, Limousine, Slovak Simmental, Pinzgau, Beef Simmental) during the period 1990-2017 were exploited. The primary analyses showed that there exist differences in the incidence of the difficult calvings according to the breed of the dam. The lowest rate of assisted calvings was observed in Limousine breed. Lower incidence was observed when calvings of crossbred matings were considered. Only slight associations of difficult calvings with sex of calves, parity and season of calvings were observed. Slightly higher rates of assisted calvings were observed in the group of heifers and births of males. Keywords: beef cattle, calving ease, dystocia, reproduction References Atashi, H., Abdolmohammadi, A., Dadpasand, M., Asaadi, A. (2012) Prevalence, risk factors and consequent effect of dystocia in Holstein dairy cows in Iran. Asian-Australasian Journal of Animal Science, 25 (4), 447-451. DOI: https://dx.doi.org/10.5713/ajas.2011.11303 Carnier, P., Albera, A., Dal Zotto, R., Groen, A. F., Bona, M., Bittante, G. (2000) Genetic parameters for direct and maternal calving ability over parities in Piedmontese cattle. Journal of Animal Science, 78 (10), 2532-2539. DOI: https://dx.doi.org/10.2527/2000.78102532x De Amicis, I., Veronesi, M.C., Robbe, D., Gloria, A., Carluccio, A. (2018) Prevalence, causes, resolution and consequences of bovine dystocia in Italy. Theriogenology, 107, 104-108. DOI: https://dx.doi.org/10.1016/j.theriogenology.2017.11.001 Eriksson, S., Nasholm, A., Johansson, K., Philipsson, J. (2004) Genetic parameters for calving difficulty, stillbirth, and birth weight for Hereford and Charolais at first and later parities. Journal of Animal Science, 82 (2), 375-383. DOI: https://dx.doi.org/10.1093/ansci/82.2.375 Fuerst, C., Egger-Danner, C. (2003) Multivariate genetic evaluation for calving ease and stillbirth in Austria and Germany. [Online] Interbull bulletin, 31, 47 - 51. Available at: http://agtr.ilri.cgiar.org/documents/Library/docs/Interbull/bulletin31_files/docs/Fuerst.pdf [Accessed 5 March 2018] Jamrozik, J., Miller, S.P. (2014) Genetic evaluation of calving ease in Canadian Simmentals using birth weight and gestation length as correlated traits. Livestock Science, 162, 42-49. DOI: https://dx.doi.org/10.1016/j.livsci.2014.01.027 Juozaitiene, V., Juozaitis, A., Kardisauskas, A., Zymantiene, J., Zilaitis, V., Antanaitis, R., Ruzauskas, M. (2017) Relationship between dystocia and the lactation number, stillbirth and mastitis prevalence in dairy cows. Acta Veterinaria. Brno 86, 345-352. DOI: https://dx.doi.org/10.2754/avb201786040345 Lopez De Maturana, E., Ugarte, E., Komen, J., Van Arendonk, J. (2007) Consequences of selection for yield traits on calving ease performance. Journal of Dairy Science, 90 (5), p. 2497-2505. DOI: https://dx.doi.org/10.3168/jds.2006-415 McHugh, N., Cromie, A. R., Evans, R. D., Berry, D. P. (2014) Validation of national genetic evaluations for maternal beef cattle traits using Irish field data. Journal of Animal Science, 92, 1423-1432. DOI: https://dx.doi.org/10.2527/jas.2013-6658 Mekonnen, M., Moges, N. (2016) A Review on Dystocia in Cows. European Journal of Biological Sciences, 8 (3), 91-100. DOI: https://dx.doi.org/10.5829/idosi.ejbs.2016.91.100 Motus, K., Emanuelson, U. (2017) Risk factors for on-farm mortality in beef suckler cows under extensive keeping management. Research in Veterinary Science, 113, 5-12. DOI: https://dx.doi.org/10.1016/j.rvsc.2017.08.007 Phocas, F., Laloe, D. (2004) Genetic parameters for birth and weaning traits in French specialized beef cattle breeds. Journal of Dairy Science, 89 (2-3), 121-128. DOI: https://dx.doi.org/10.1016/j.livprodsci.2004.02.007 Steinbock, L., A. Nasholm, B. Berglund, K. Johansson, And J. Philipsson. (2003) Genetic effects on stillbirth and calving difficulty in Swedish Holsteins at first and second calving. Journal of Dairy Science, 86 (6), 2228-2235. DOI: https://dx.doi.org/10.3168/jds.S0022-0302(03)73813-2 Uematsu, M., Sasaki, Y., Kitahara, G., Sameshima, H., Osawa, T. (2013) Risk factors for stillbirth and dystocia in Japanese Black cattle. The Veterinary Journal, 198 (1), 212-216. DOI: http://dx.doi.org/10.1016/j.tvjl.2013.07.016

Rumination time and reticuloruminal temperature as possible predictors of dystocia in dairy cows

The objectives of this study were to explore changes of rumination time and reticuloruminal pH and temperature of dairy cows and heifers (means ± standard deviation; age = 5.8 ± 1.9; parity = 2.7 ± 1.4; body condition score = 3.2 ± 0.2) with eutocic (EUT, n = 10) and dystocic calving (DYS, n = 8). The recording period lasted from 3 d before calving until 7 d in milk. For the comparison of rumination time and reticuloruminal characteristics between groups, time to return to baseline (the time interval required to return to baseline from the delivery of the calf) and area under the curve (AUC; both for prepartum and postpartum periods) were calculated for each parameter. Rumination time decreased from baseline 28 h before calving both for EUT and DYS cows; after 20 h before calving, it decreased to 32.4 ± 2.3 and 13.2 ± 2.0 min/4 h between 8 and 4 h before delivery in EUT and DYS cows, respectively, and then it decreased below 10 and 5 min during the last 4 h before calving. Until 12 h after delivery, rumination time reached 42.6 ± 2.7 and 51.0 ± 3.1 min/4 h in DYS and EUT dams, respectively; however, AUC and time to return to baseline suggested lower rumination activity in DYS cows than in EUT dams for the 168-h postpartum observational period. Reticuloruminal pH decreased from baseline 56 h before calving both for EUT and DYS cows, but did not differ between groups before delivery. Reticuloruminal pH showed a decreasing tendency and clear diurnal variation after calving for both EUT and DYS cows, with slightly higher AUC values in DYS cows. In DYS cows, reticuloruminal temperature decreased from baseline 32 h before calving by 0.23 ± 0.02°C, whereas in EUT cows such a decrease was found only 20 h before delivery (0.48 ± 0.05°C). The AUC of reticuloruminal temperature calculated for the prepartum period was greater in EUT cows than in DYS cows. During the first 4 h after calving, reticuloruminal temperature decreased from 39.68 ± 0.09 to 38.96 ± 0.10°C and from 39.80 ± 0.06 to 38.81 ± 0.08°C in EUT and DYS cows, respectively, and reached baseline levels after 35.4 ± 3.4 and 37.8 ± 4.2 h after calving in EUT and DYS cows, respectively. Based on our results, continuous monitoring of changes in rumination time and reticuloruminal temperature seems to be promising in the early detection of cows with a higher risk of dystocia. Depressed rumination activity of DYS cows after calving highlights the importance of the postpartum monitoring of cows experiencing difficulties at calving. The effect of dystocia on postpartum reticuloruminal pH was not pronounced.

Environmental and genetic factors affecting cow survival of Israeli Holsteins

The objectives were to investigate the effects of various environmental factors that may affect herd-life of Israeli Holsteins, including first-calving age and season, calving ease, number of progeny born, and service sire for first calving in complete and truncated records; and to estimate heritabilities and genetic correlations between herd-life and the other traits included in the Israeli breeding index. The basic data set consisted of 590,869 cows in milk recording herds with first freshening day between 1985 and at least 8 yr before the cut-off date of September 15, 2013. Herd-life was measured as days from first calving to culling. The phenotypic and genetic trends for herd-life were 5.7 and 16.8d/yr. The genetic trend was almost linear, whereas the phenotypic trend showed 4 peaks and 3 valleys. Cows born in February and March had the shortest herd-life, whereas cows born in September had the longest herd-life. Herd-life was maximal with calving age of 23mo, which is 1mo less than the mean calving age, and minimal at 19 and 31mo of calving age. Dystocia and twinning on first-parity calving reduced herd-life by approximately180 and 120d, but the interaction effect increased herd-life by 140d. Heritability for herd-life was 0.14. Despite the fact that the service sire effect was significant in the fixed model analysis, service sire effect accounted for <0.05% of the total variance. In the analysis of 1,431,938 truncated records, the effects of dystocia and twinning rate were very similar but less than 50% of the effects found in the analysis of complete records. Pregnancy at the truncation date increased expected herd-life by 432d. The correlation between actual herd-life and predicted herd-life based on truncated records was 0.44. Genetic correlations between the truncated records and actual herd-life were 0.75 for records truncated after 6mo but approached unity for records truncated after 3 yr. The genetic correlations of herd-life with first-parity milk, fat, and protein production, somatic cell score (SCS), and female fertility were all positive, except for SCS, in which negative values are economically favorable. The highest correlations with herd-life in absolute value were with female fertility and SCS.

Prevalence, risk factors and consequent effect of dystocia in holstein dairy cows in iran.

The objective of this research was to determine the prevalence, risk factors and consequent effect of dystocia on lactation performance in Holstein dairy cows in Iran. The data set consisted of 55,577 calving records on 30,879 Holstein cows in 30 dairy herds for the period March 2000 to April 2009. Factors affecting dystocia were analyzed using multivariable logistic regression models through the maximum likelihood method in the GENMOD procedure. The effect of dystocia on lactation performance and factors affecting calf birth weight were analyzed using mixed linear model in the MIXED procedure. The average incidence of dystocia was 10.8% and the mean (SD) calf birth weight was 42.13 (5.42) kg. Primiparous cows had calves with lower body weight and were more likely to require assistance at parturition (p<0.05). Female calves had lower body weight, and had a lower odds ratio for dystocia than male calves (p<0.05). Twins had lower birth weight, and had a higher odds ratio for dystocia than singletons (p<0.05). Cows which gave birth to a calf with higher weight at birth experienced more calving difficulty (OR (95% CI) = 1.1(1.08–1.11). Total 305-d milk, fat and protein yield was 135 (23), 3.16 (0.80) and 6.52 (1.01) kg less, in cows that experienced dystocia at calving compared with those that did not (p<0.05).

Prevalence of, and risk factors associated with, perinatal calf mortality in pasture-based Holstein-Friesian cows

Recent publications indicate that the prevalence of perinatal mortality has increased in some dairy industries and an increased proportion of this loss is not associated with the traditional risk factors for perinatal mortality. The objectives of this study were to establish the prevalence of perinatal mortality (calf death within 24 h of calving) in Irish dairy herds and to determine the current significance of putative risk factors in pasture-based management systems. A total of 182 026 records of full-term calvings from Holstein-Friesian dams served by artificial insemination (AI) sires of seven breeds in herds of 20 calvings or more per year were available from the Irish national breeding database over 4 years (2002 to 2005). The prevalence of perinatal mortality was 4.29% (7.7% in primiparae and 3.5% in pluriparae). The likelihood of perinatal mortality increased between 2002 and 2005 and was greatest in June and in winter. There was an interaction (P < 0.001) between the effect of calving assistance and parity with the effect of dystocia on perinatal mortality being greater in primiparae. The odds of perinatal mortality were greater in male (OR = 1.12; P < 0.001) and in twin calves (OR = 5.70-13.36; P < 0.001) and in dams that had perinatal mortality at the previous calving (OR = 4.21; P < 0.001). The logit of the probability of perinatal mortality increased by 0.099 per unit increase in sire predicted transmitting ability (PTA) for direct perinatal mortality. The probability of perinatal mortality increased at an increasing rate in primiparae as animals calved at a younger age relative to the median age at first calving. The only herd-level factor examined, herd size did not affect the odds of perinatal mortality. These data indicate that the prevalence of perinatal mortality in this cattle population is similar to that in other pasture-based dairy systems worldwide. The putative exposures and attributes traditionally associated with perinatal mortality were associated with perinatal mortality in this pasture-based dairy cow population. The practical implication of these results is that as many of the significant risk factors are largely not under management control (year of calving, month of calving, twin calving, primiparity, previous perinatal mortality and foetal gender), herd owners must focus on the significant determinants under their control (age at first calving, sire genetic merit for direct perinatal mortality and both the extent of calving supervision and the degree of assistance), in order to reduce the prevalence of perinatal mortality and improve perinatal welfare.

Effects of dystocia, fetotomy and caesarian sections on the liver enzymes activities and concentrations of some serum biochemical parameters in dairy cattle

The aim of the present study was to determine the level of serum liver enzymes, triglyceride and some metabolites in cows with or without difficulties during parturition. The second goal was to compare between the possible effects of caesarian section and fetotomy on these parameters. A total number of 24 native breed cows at full term were included in this study. Out of them, 8 gave normal parturition, 16 cows were admitted with dystocia. The group of dystocia was subdivided into two groups; fetotomy ( n = 8) and caesarian ( n = 8) group. In the caesarian group, 4 cows were with uterine torsion. Five blood samples were collected from each cow: directly pre-partum, during and just after delivery and at, 24, 48 and 72 h post-partum. Serum samples were used for determination of aspartate amino transferase (AST), glutamate dehydrogenase (GLDH), gamma glutamyl transferase (γ-GT), creatine phosphokinase (CK), glucose, total bilirubin, cholesterol and triglyceride. The results showed that AST, GGT, GLDH and CK activities were significantly increased in the group with caesarian sections due to uterine torsion than the control and fetotomy groups. There were insignificant changes in serum GGT and GLDH activities between control, fetotomy and dystocia group without uterine torsion at pre-partum and at 24 and 48 h post-partum. At 72 h post-partum, there was a significant increase in GLDH activity without significant increase in serum GGT activity. The concentrations of cholesterol and triglycerides did not differ in cows with dystocia compared to normal cows. In conclusion, cattle subjected to caesarian section and especially those with uterine torsion are associated with hepatic dysfunction. On the other hand, fetotomy has no effect on hepatocellular damage. The type of parturition has no effect on the bilirubin, cholesterol and triglyceride concentrations just before parturition to the 3rd day post-partum. It is recommended to supply cows with liver supportive therapy after caesarian section with uterine torsion.

The effect of dystocia and previous cesarean uterine scar on the tensile properties of the lower uterine segment

The remodeling of uterine connective tissue during labor can lead to the reorganization of the extracellular matrix that, in turn, may influence the biomechanical properties of the myometrial wall. We hypothesized that the stretching of the lower uterine segment in laboring women with dystocia changes the viscoelastic properties of the uterine wall. We tested the tensile strength of lower uterine segment myometrium in 68 pregnant women at term. The biomechanical, structural, and biochemical properties were compared among 3 groups: (1) 39 laboring women who underwent primary low-transverse cesarean delivery for labor dystocia, (2) 12 nonlaboring women who underwent primary elective low-transverse cesarean delivery and (3) 17 women who underwent an elective repeat low-transverse cesarean delivery at term. The tensile properties were quantitated with a stretching regimen that was designed to mimic the conditions of labor. Parameters such as slope, yield point, and break point were recorded, analyzed, and interpreted. Biochemical properties were determined by the measurement of the sulfated glycosaminoglycans, hydroxyproline, and pyridinoline-deoxypyridinoline. Histologic properties of the connective tissue were assessed by collagen birefringence. Lastly, the association between these properties and biomechanical responses were compared among groups. Lower uterine segment myometrium specimens obtained from laboring women were stiffer compared with specimens from women who were not in labor (P = .013) or had scarred myometrium (P < .001). The force that was required to reach the yield point was similar between labor and nonlabor groups (P = .216). Likewise, a previous lower uterine segment scar did not alter the yield point. The break point was similar among all groups (P = .317). Sulfated glycosaminoglycan levels were unaffected by labor or scarring (P = .354). Scarred lower uterine segment myometrium had a higher collagen content compared with unscarred myometrium specimens that were obtained during labor (P = .025). Although there were similar degrees of collagen cross-linking among groups (P = .212), there was lower collagen birefringence in myometrium from laboring women compared with nonlaboring women (P < .001). Labor alters the viscoelastic properties of myometrium. Lower uterine segment myometrium is stiffest in women with dysfunctional labor compared with nonlabor control subjects. Labor and scarring also alter the pattern of collagen birefringence. Similar collagen cross-linking among the study groups may explain the reason that the breaking strength of the tissue is not altered by the state of labor and the reason that the rupture of the uterine scar is a rare event.

Effects of Dystocia on Dam Health and Productivity

The effects of dystocia on dam health and productivity are rarely monitored on dairy farms. It is highly likely that the effects of dystocia on health and production are substantial. The objectives of this year-long longitudinal study were to measure proportion of dams experiencing dystocia on three Front Range Colorado dairies and evaluate associations with dam productivity, morbidity and mortality.

Effects of severity of dystocia on cold tolerance and serum concentrations of glucose and cortisol in neonatal beef calves

Effects of dystocia on rectal temperature and serum Cortisol and glucose concentrations, were studied in neonatal calves exposed to 0 °C. Primiparous dams were observed continuously during parturition and if Stage II (labor) was not completed within 2 h after appearance of the allantochorion, delivery was completed with obstetrical assistance. Parturitions were scored (CDS) for difficulty and obstetric assistance required: CDS 1, no assistance (n=8); CDS 2, minor manual assistance (n=7); CDS 3, use of a mechanical calf puller (n=5); CDS 4, cesarean section (n=6). A blood sample, rectal temperature, and body weight were obtained within 30 min after birth. Calves were then fed 38 °C pooled colostrum, muzzled to prevent suckling, and placed back with their dam in a heated (22 °C) barn. At 4 h of age an indwelling jugular catheter was inserted. At 5 h of age calves were placed in a 0 °C room for 140 min and blood samples and rectal temperatures were obtained every 10 or 20 min. A shivering score (1 = no shivering; 2 = moderate shivering; 3 = intense shivering) was assigned at each sampling time. Rectal temperatures were higher (P < 0.01) in CDS 1, 2 and 4 calves (39.0, 39.3, and 39.0 ± .02 °C, respectively) than in calves with CDS 3 (38.3 ± 0.02 °C) and were affected by duration of cold exposure (time; P < 0.01). Shivering was not affected by CDS but was affected by time (P<0.01). Glucose concentrations were higher (P < 0.01) in CDS 3 calves (110.1 ± 1.6 mg/dL) than in CDS 1, 2, or 4 calves (77.2, 86.4, and 89.0 ± 1.3 mg/dL, respectively) and changed over time (P < 0.01). Cortisol concentrations were higher in CDS 1 calves (80.0 ± 1.7 ng/mL) than in CDS 2, 3 or 4 calves (62.7, 58.2, and 57.7 ± 2.0 ng/mL, respectively) and were affected by time (P < 0.01). We conclude that severe dystocia (CDS 3) resulted in lower calf rectal temperature, reduced serum cortisol, and increased serum glucose which could affect the ability of the calf to withstand cold stress. Minor dystocia did not cause and timely cesarean delivery prevented, the physiological aberrations encountered in severe dystocia.

Effects of dystocia and confined calving on calf-morbidity rate from birth to weaning (2000)

An analysis was performed on data from a national survey of US beef cow-calf producers to quantify the effects of management factors on calf-morbidity risk from birth to weaning. The analysis included 2,490 herds from 23 states. A high calf-morbidity herd was defined as one with greater than 10% morbidity. The rate of dystocia in the herd was categorized into five levels. All dystocia levels were associated significantly with increased risk of being a high calf-morbidity herd. Having greater than 70% of cows and heifers calve in confinement also was associated with increased risk of being a high calf-morbidity herd. Approximately 40% of herds experienced high morbidity from the effect of dystocia and approximately 10% from the effect of confined calving. This analysis indicates that dystocia and confined calving are important factors in determining a herd’s calfmorbidity rate from birth to weaning.

Effects of Dystocia, Retained Placenta and Body Condition on Plasma .BETA.-Endorphin Profile in Periparturient Dairy Cows.

The aims of this study were to determine profiles of plasma immunoreactive β-endorphin (ir-β-EP) during peripartum period in dairy cows, and to examine whether dystocia, retained placenta or body condition affects the plasma ir-β-EP level. Blood samples were collected from 21 Holstein-Friesian cows from day 180 of pregnancy until first ovulation. The cows were classified into two groups based on calving conditions and ir-β-EP patterns at parturition. Seven out of the 21 cows had normal parturition and 14 cows had abnormal parturition (dystocia and/or retained placenta). The proportion of cows which had ir-β-EP elevation at parturition tended to be higher in cows with abnormal parturition (11/14; 79%) than in those with normal parturition (3/7; 42%). Plasma cortisol level increased at parturition both in cows with ir-β-EP elevation and in cows without ir-β-EP elevation at parturition. Postpartum ir-β-EP concentrations in plasma were similar between cows with normal parturition and those with abnormal parturition, and between cows which had lost their body condition score (BCS) after calving and those which had maintained their BCS. In conclusion, abnormal parturition may affect plasma ir-β-EP level at parturition but not postpartum period.

Factors influencing dystocia and prediction of dystocia in Angus heifers selected for yearling growth rate

Data on 914 Angus heifers and their calves that had been selected for yearling growth rate (from birth to 1 year of age) were used to (i) evaluate the effect of dystocia on subsequent cow and calf performance, (ii) identify factors influencing dystocia, and (iii) develop and validate equations for predicting dystocia. Records on heifers born in the high, control, and low growth selection lines from 1975 to 1990 and their calves were used. Calving was classified as normal (no assistance), with a code of 0, or difficult (requiring assistance), with a code of 1. The incidence of dystocia was 4.5%, 9.7%, and 6.2% in the high, control, and low lines, respectively, with the difference between the high and control lines being significant (P &lt; 0.05). Dystocia resulted in a significant reduction in calf survival to weaning (97% for normal v. 85% for difficult calvings). Of all the calving and pre-calving traits studied, the ratio of calf birth weight to heifer weight accounted for the highest variation in dystocia in the control (19.6%), low (15.2%), and high (5.4%) lines. The total variation explained by models generated by stepwise regression and discriminant analyses ranged from 5.4% to 36.8%. Prediction equations developed by discriminant analysis using traits measured prior to calving had high accuracy of predicting normal calvings (72.6%–90.3%), when tested on independent data sets. However, the sensitivity (ability to identify those heifers having difficult birth) of the equations was low (0%–40%). These results imply that the approach to be used to reduce dystocia and minimise its effects is to develop an overall management strategy involving both planning of mate selection at joining and supervision at calving.

Effects of Dystocia, Retained Placenta, and Metritis on Milk Yield in Dairy Cows

The effects of dystocia, retained placenta, and metritis on milk yield were studied in 37,776 Finnish Ayrshire cows that calved during 1993; cows were studied for one lactation. Monthly test day milk yields were treated as repeated measurements within a cow in a mixed models analysis. Index categories were created to relate the time of disease occurrence to the test dates and to capture the short-term effects of diseases on milk yield. Diseases other than dystocia, retained placenta, or metritis were categorized into two groups: diseases occurring within 42 d after calving or diseases occurring later than that.The statistical models for each parity included calving season, stage of lactation, and disease variables as fixed effects. For parities 2, 3, and 4 or higher, the cows were grouped into four categories based on previous lactation milk yield, and the disease effect was studied separately for each yield level. An autoregressive covariance structure was used to model the association among the repeated measurements. Models with a 305-d yield as the outcome were also run; the diseases were treated as binary covariates in these models.Dystocia, retained placenta, and early metritis significantly affected milk yield, as indicated by monthly test day milk yields. Late metritis was not associated with milk loss. The impact of the diseases differed across parities and also across different levels of milk yield. Using 305-d milk yield as the milk measure, no diseases were associated with reduced milk yield.

Effect of Dystocia on Yield, Fertility, and Cow Losses and an Economic Evaluation of Dystocia Scores for Holsteins

Lactation records of US Holstein cows were analyzed with mixed models to determine the effect of dystocia on 305-d milk, fat, and protein yields, days open, number of services, and cow losses and to estimate the economic loss associated with dystocia. The data were 122,715 records of 71,618 cows from 1980 to 1991. The single-trait animal model included herd-year-season, sex of calf, age of dam, and dystocia score as fixed effects and animal and permanent environment as random effects. The effect of dystocia was significant (P<0.01) on all traits within and across parities. Over multiple parities, the differences between score 5 (extreme difficulty) versus score 1 (no problem) for milk yield, fat yield, protein yield, days open, number of services, and cow deaths were 703.6kg, 24.1kg, 20.8kg, 33 d, 0.2 services, and 4.1%, respectively. The losses associated with traits were priced and summed to determine the total economic loss associated with dystocia. In addition, calf mortality was considered to be a cost. Across parities, estimates of costs were $0.00, $50.45, $96.48, $159.82, and $379.61 for scores 1 to 5, respectively. Cost of dystocia was relatively higher on a per incidence basis than would be expected from the mean of the population. The total cost associated with dystocia (i. e., within-parity sum of costs associated with dystocia scores weighted by the probability of occurrence) was $28.53 for an average heifer and about $10.00 for an average cow for other parities.

Effects of twinning on dystocia, calf survival, calf growth, carcass traits, and cow productivity.

This paper reports results from a long-term experiment with a primary objective to increase twinning rate in cattle at the Roman L. Hruska U.S. Meat Animal Research Center. Survival of singles was 13% higher (P < .01) than that of twins at birth, and the difference in survival in favor of singles was of similar magnitude at 72 h (12.9%, P < .01), 150 d (14.8%, P < .01), and 200 d (15.2%, P < .01). Survival of calves with no dystocia was higher than survival of calves with dystocia: 8.6% (P < .01) at birth, 10.8% (P < .01) at 72 h, 12% (P < .01) at 150 d, and 12.2% (P < .01) at 200 d. The effect of dystocia on survival was greater (P < .01) in twins than in singles at birth and at 72 h. Least squares means for dystocia were 20.4% in singles compared with 42.2% in twins. Most of the dystocia in singles resulted from a traction requirement (84.7%) of normal presentations, whereas most of the dystocia in twins (77.8%) resulted from malpresentations, with 59.2% of the malpresentations accompanied with a requirement for traction. Survival in singles ranged from 10.7% to 15.3% greater than in twins at different ages when there was no requirement for assistance in either singles or twins. Calves born as singles were 8.8 kg heavier (P < .01) at birth and 28 kg heavier (P < .01) at 200 d than calves born and reared as twins. Calf weight produced per cow calving was 53.1%, 54.7%, and 58.4% greater (P < .01) at birth, 150 d, and 200 d, respectively, in cows producing twins than in cows producing singles. Cows producing twins had 65.2% more (P < .01) live calves at 200 d than cows producing singles. Single male calves gained 74 g more per day than twin males from birth to 200 d, 45 g more (P < .01) per day from 200 d to slaughter and 57 g more (P < .01) per day from birth to slaughter. Differences between twin and single males in carcass traits were small. A sample of steers from the Twinning Project gained significantly faster and produced significantly more desirable carcasses than a sample of steers from a high performance reference population. Freemartins did not differ (P < .05) from normal females in growth traits, but freemartins had higher (P < .05) scores for marbling with a higher percentage (P < .05) of USDA Choice or better quality grade carcasses and lower estimated percentage retail product.

Antiprogesterone, RU 486, Facilitates Parturition in Cattle*

RU 486, a potent progesterone antagonist with high affinity for progesterone receptor, was used alone or in combination with relaxin in late pregnant cattle to determine its effect on induction of parturition. Cross-bred beef cattle were bred by artificial insemination. An indwelling cannula was inserted into a jugular vein on day 269 (expected term = day 283) for repeated blood sample collection. On day 277, the cattle were assigned randomly to three groups (n = 6 each): group 1 received RU 486 (2 mg/kg BW, im) at 0800 h on days 277 and 278; group 2 received the same RU 486 treatment plus 3000 U relaxin, injected sc at 0800 h on day 278; and group 3 served as controls and received vehicle injection. Parturition occurred 55 h after treatment in group 1 and 53 h after treatment in group 2 compared with 210 h in the controls (P less than 0.01). The calves from treated groups were vigorous at birth, and their birth weights (32 and 33 kg in groups 1 and 2) were less than those of control calves (38 kg; P less than 0.01). There was no incidence of difficult birth (dystocia) with RU 486 treatment compared with that in the controls. Placenta delivery averaged 6.5 h after birth in both RU 486-treated groups and did not differ from the control value (5 h). Plasma progesterone concentrations averaged 8.2 ng/ml during the pretreatment period for all animals. Progesterone started to decrease markedly by 1200 h on day 278, dropped to about 4 ng/ml by 2400 h that same day, and was at basal levels on day 279, the day of calving, in two hormone-treated groups. In sharp contrast, progesterone was maintained at about 6 ng/ml in placebo-treated controls during this period and did not decrease to basal levels until 2 days before parturition on day 286 (P less than 0.01). Peak RU 486 in plasma was 7.2 ng/ml after the first injection and 14.3 ng/ml after the second injection, and averaged 7.9 ng/ml on the day of induced calving (day 279). Peak relaxin was 4.1 ng/ml after hormone injection. The results indicate that RU 486 alone or combined with relaxin precisely controlled the time of parturition in cattle in late pregnancy. Such treatment can be used to facilitate parturition and increase survival rates of neonatal calves without detrimental effects of dystocia, retention of placenta, and delayed postpartum fertility.

Effects of Dystocia on Postpartum Adrenocortical Function in Dairy Cows

Postpartum adrenocortical responses to adrenocorticotropic hormone in cows after normal (n=10) and difficult (n=52) parturition were investigated. The postpartum adrenocortical function of cows was affected by type of parturition (spontaneous parturition, forced extraction of fetus, caesarean section calving with or without attempted forced extraction, and total fetotomy) and day after calving (d 1, 4, and 8; d 0 = day of parturition). Cows after normal calving did not show enhanced or depressed adrenocortical function postpartum. Adrenocortical function was enhanced, compared with cows calving normally, for cows with dystocia that had a caesarean section after forced extraction was attempted and in cows in which calves were already dead and total fetotomy was performed. Cows with dystocia assisted with forced extraction by one to two people and cows that had caesarean sections without forced extraction did not show higher plasma glucocorticoid concentrations before or after adrenocorticotropic hormone administration than did cows with normal calving. Results indicate that dystocia requiring caesarean section following unsuccessful extraction or total fetotomy enhanced postpartum adrenocortical function in cows.

Reporting of Dystocia Scores and Effects of Dystocia on Production, Days Open, and Days Dry from Dairy Herd Improvement Data

Dystocia and livability scores are collected through the Mid-States Dairy Records Processing Center. Thirty-four percent of the cows had dystocia scores reported. Least difficult births were scored 1 and the most difficult births scored 5. Days open in first parity were 14 d greater for births scored 5 versus 1. The differences were larger in later parities. There were 26 more d open in second parity and 19 more d open in third and greater parities for score 5 versus 1. Differences between cows scored 5 versus 1 were 465kg milk and 20.7kg milk fat in first lactations, 576kg milk and 20.9kg milk fat in second lactations, and 725kg milk and 25kg milk fat in third and greater lactations. Cows produced more in lactations following an easy birth. Frequency of difficult births was less in lactations other than the first.