Impact of Calving Difficulty on Lameness in Dairy Cows

The aims of our study were to evaluate the associations between calving difficulty and lameness and their effects on milk yield and quality traits. A total of 4723 calving cases were evaluated for calving difficulty using a 4-point scoring system. Lameness was diagnosed with a visual locomotion score system from 1 to 30 days after calving in 333 fresh dairy cows. Cows were divided into non-lame cows and lame cows. Milk quality traits were registered using Lely Astronaut ® A3 milking robots. The normal distribution of all indicators was assessed using the Shapiro–Wilk normality test. Normally distributed milk indicators were expressed as mean ± standard error of the mean. Differences between the mean values of their groups were determined using the Fisher’s least significant difference test. We categorized cows by health status, i.e., lame (LA) and non-lame (HL) cows, and according to calving difficulty (CD) (on a 4-point scale: 1—no problem, 2—slight problem, 3—problems requiring assistance, 4—considerable force and extreme difficulty). In the present study, calving difficulty increased the risk of lameness in cows by 2.09-fold (95% CI = 1.644–2.650, p < 0.001). It was found that the mean standard milk yield in fresh dairy cows with calving difficulty was lower (−6.14 kg, p < 0.001) than in the group where no assistance was required at calving. Similarly, herd affected milk fat (%) and the calving process—herd and the interaction between calving difficulty and herd—and lameness impacted the quantity of milk protein and lactose in cows. We found that severe lameness (3–4 points) (3.88–5.92% of cows) became more prevalent in those cows that had dystocia than those that did not (0.27–2.37% of cows).