Dairy cow management has evolved tremendously in recent decades, particularly regarding reproductive techniques. The widespread adoption of synchronization protocols, sexed semen, beef semen in dairy cows, reproductive biotechnologies such as in vivo-derived (IVD) or in vitro-produced embryos (IVP), and precision livestock farming is transforming the daily practices of dairy farmers and veterinarians. These implementations are typically adapted in different ways when applied to the breeding of heifers or cows. Considering these developments, dystocia—a significant welfare and productivity concern—may warrant reevaluation. The aforementioned changes are likely to have a substantial impact on its prevalence, severity, and outcome. This review aims to address the main aspects of dystocia in dairy cows and heifers, with a particular focus on the potential impact of recent advances in reproductive and calving management.

The purpose of this study was to assess the ovarian and energy status of multiparous lame dairy cows at the end of puerperium and investigate their responsiveness to estrous synchronization treatment regimens. Initial lameness scoring was performed at 28 ± 5 and 37 ± 5 d post partum, followed by lesion documentation and treatment. Cows were blocked by lameness severity and were randomly allocated to an estrous synchronization treatment regimen with seven days of progesterone supplementation (group LP, n = 26) or with an administration of PGF_2α twice, 14 d apart (group LC, n = 26). Non-lame cows served as controls (group C, n = 27) and the same treatment regimen was imposed as that for group LC. Twelve days after estrous presynchronization, an Ovsynch treatment regimen and timed AI were imposed. Ultrasonography of the ovaries and blood sampling for progesterone were used to assess cyclicity status, whereas β-hydroxybutyrate (BHBA) and non-esterified fatty acids (NEFA) were used to assess energy status. Lame cows were to a greater proportion non-cycling (36.5% vs. 11.1%; p = 0.02), had greater overall NEFA concentrations (0.32 ± 0.02 vs. 0.26 ± 0.02 mEq/L; p = 0.02) and a greater incidence of elevated NEFA concentrations (53.9% vs. 29.6%, p = 0.04) compared to control cows. However, no interaction between energy and lameness status was evident regarding non-cycling cows. The percentage of cows responding to the presynchronization, synchronization and ovulating did not differ between groups LP, LC, and C. The first-service conception rate (FSCR) tended to be greater for group C (37.0%) compared to group LP (16.0%; p = 0.08). Long-term reproductive performance did not differ between lame and control cows, although culling rates did (21.2% vs. 0%, respectivly; p = 0.01). The severity of lameness had an effect on culling rates (30.6% vs. 0% for cows with marked vs. moderate lameness; p = 0.01), whereas the type of lesion largely explained poor reproductive performance (FSCR 13.9% vs. 40.0% for cows with claw horn disruptions vs. infectious lesions; p = 0.04). Conclusively, cows that were lame during puerperium are at a greater risk of not cycling irrespective of energy status. Treatment regimens for the synchronization of ovulation seem to be efficient at resuming ovarian cyclicity. Marked lameness was detrimental to survivability, whereas cows with claw horn lesions had compromised reproductive capacity.

The aim of the study was to examine the effect of lameness and energy status on the involution of the uterus and the resumption of ovarian cyclicity in dairy cows. Lame (lameness score of four and the presence of hoof lesions, n = 22) and sound (normal gait and the absence of hoof lesions, n = 25) multiparous cows with healthy puerperium were enrolled simultaneously in the study and were monitored from day 10 antepartum (ap) to day 50 post-partum (pp). Ultrasonography of the cervix, the formerly gravid uterine horn and the ovarian structures was performed on d 8, 11, 14, 23, 30, and 42 pp. Blood sampling for progesterone, β-hydroxybutyrate (BHBA), and non-esterified fatty acids (NEFAs) was used to assess cyclicity and energy status. Lame compared to sound cows had higher NEFA concentrations on day 14 pp (0.54 ± 0.05 vs. 0.37 ± 0.05, respectively, p = 0.005), delayed involution of the cervix and the formerly pregnant uterine horn (p = 0.0003 and p = 0.02, respectively), lower ovulation rates within the experimental period (63.6% vs. 88%, respectively, p = 0.05), and higher rates of atresia or cyst formation on day 50 pp (36.4% vs. 12%, respectively, p = 0.05). Independently of lameness status, cows with high NEFA concentrations had lower ovulation rates within the experimental period (65.5% vs. 94.4%, p = 0.02), lower normal ovarian activity on day 50 pp (58.6% vs. 88.9%, p = 0.03), and higher rates of atresia or cyst formation on day 50 pp (34.5% vs. 5.6%, p = 0.02) compared to cows with optimal NEFA concentrations. Furthermore, an interaction between lameness and increased NEFA concentrations was observed regarding the ovulation rate within the experimental period and the percentage of atresia or cyst formation on day 50 pp. Sound cows with low NEFA levels had the lowest mean cervical diameter compared to cows with lameness (both with elevated and optimal NEFA concentrations, p = 0.009 and p = 0.002, respectively). Conclusively, lameness during puerperium negatively affected ovarian function and uterine involution. These effects were exacerbated (through interaction or cumulation) in relation to elevated NEFA concentrations.

This study presents findings from two discrete experimental processes that examined the impact of lameness events on two consecutive, critical time points in the annual production cycle of dairy cattle (early in puerperium—first study, and later at the onset of the reproductive period—second study) regarding liver function, glucose levels, milk production, body condition score, and back fat thickness. In the first study, 47 cows (lame group n = 22, control group n = 25) were monitored from 10 days ante partum (ap) to 46 days post-partum (pp). In the second study, 79 cows (lame group n = 52, control group n = 27) were monitored from day 28 ± 5 pp to day 65–72 ± 5 pp. Lame cows had greater gamma-glutamyl transferase (GGT) concentrations in the blood serum compared to control cows (25.83 vs. 23.56, p = 0.02, respectively) early in puerperium, whereas the two groups did not differ in the second study. The concentration of glutamate dehydrogenase (GLDH) was lower for lame compared to control cows in both studies (17.24 vs. 24.60, respectively, p = 0.02 in the first study, and 30.50 vs. 51.10, respectively, p = 0.02 in the second study). The concentrations of aspartate transaminase (AST) and glucose did not differ between groups in both studies. Lame cows had a lower body condition score (BCS) and backfat thickness (BFT) scores compared to the control in both studies overall. The lame cows of the first study experienced a significant loss of milk production, especially during the second month of lactation, while in the second study, milk production remained unaffected. Conclusively, lame cows have lower BCS and BFT values, whereas milk yield can be negatively affected only if lameness occurs early in the puerperium, probably beginning at the dry period. However, the current research shows that acutely lame cows, as described in this study, exhibit only mild alterations in liver function compared to non-lame ones.

The primary aim of this study was to investigate the effect of the pelvic dimensions of Holstein cows on the traction forces during parturition. Additionally, the relationship between calf measurements and traction forces was explored. For this purpose, a modified in vitro biomechanical model simulating obstetric tractions was used. For the requirements of the experiment, six bone pelvises of deceased Holstein cows were collected based on their estimated pelvic inlet area (EPA) and prepared. Additionally, six stillborn calves were collected based on their body weight (BW). The parameters of the pelvic inlet and cavity were measured using computed tomography (CT). Using the simulator, every calf was pulled in a random order through all pelvises, realizing a total of 36 obstetrical tractions, and the required forces were documented with appropriate software. In each extraction, three peaks of forces were recorded, with the first peak occurring at the entrance of the elbows into the maternal pelvic cavity, the second peak at the entrance of the thorax, and the third at the entrance of the calf’s pelvis. Logistic regression revealed an exponential relationship between pelvic parameters and traction forces for the entrance of the elbows and the pelvis, with the recorded forces being higher in the two smallest pelvises and stabilizing at a lower level thereafter, while for the entrance of the thorax, the correlations were either exponential or linear. The adjusted coefficients of determination (r²) were generally above the threshold of 0.5 for the entrance of the elbows and pelvis and lower (0.3–0.4) regarding the thorax and were statistically significant (p < 0.05) in all cases. Regarding the relationships between the calf dimensions and the required traction forces, the types of correlations were primarily linear and of lower magnitude. The combination of pelvic and calf parameters in a multivariate model resulted in an r² of 0.72 for the entrance of the elbows using the pelvic diagonal and calf’s body weight, an r² of 0.62 using the pelvic area and calf’s thoracic circumference, and an r² of 0.75 using the pelvic diagonal and calf’s fetlock joint width. In conclusion, under the conditions of the present experimentation, the applied traction forces were mainly influenced by the pelvic dimensions in an exponential manner, whereas the calf body measurements showed a weaker effect. Based on these findings, critical cut-off points exist, different for every pelvic parameter, below which a significant increase in the required traction forces is expected.