Relationship between dystocia and the lactation number, stillbirth and mastitis prevalence in dairy cows

Successful management of lactating dairy cows needs to integrate the programs of herd reproduction and health. The objectives of this study was to determine the relationship of dystocia, stillbirths, and the prevalence of mastitis in dairy cow herds. A total of 559 304 Lithuanian Black and White dairy cows were evaluated in relation to calving ease and stillbirths. Moreover, 1498 cows from the aforementioned group were tested for the milk somatic cell count and the presence of udder microbiota in the post partum period. The majority of extremely difficult births were estimated in primiparous and multiparous cows of lactations 6–8 (3.8–4.2% births) (P < 0.0001). Repeatability of dystocia was determined in 82.7% of cows in the following lactation (P < 0.0001). The stillbirth parturition rate was estimated to be 5.37% and shown to be the most important problem in the first calving compared to the second and subsequent calvings (P < 0.0001). Stillbirth was 11.2 × higher in cows with severely difficult calving compared to cows having no calving difficulties or slight calving difficulties (P < 0.0001). Dystocia significantly increased the somatic cell count (P < 0.05) and incidence of mastitis (P < 0.001), in particular mastitis caused by Streptococcus agalactiae and Staphylococcus aureus. Cattle, calf, udder health, inflammation, parturition Difficult calving (DC), or dystocia, poses a particular problem not only in terms of pain, but also in terms of the future productivity of the dam and calf (Lombard et al. 2007). Meyer et al. (2000) reported that dystocia can include stillbirth (SB), while approximately 50% of SB are a direct result of difficult calving. Dystocia also significantly decreases lactation performance (Atashi et al. 2012). Barrier and Haskell (2011) noticed that calving difficulty impaired the milk production of dairy cows affecting the cows’ productivity, and potentially impaired their health and survival. Kaya et al. (2015) found that dystocia reduced milk production during lactation in primiparous Holstein cows. Incidence of SB was higher in dystocic calvings compared with eutocic ones. Chegini et al. (2016) demonstrated that primiparous cows had lower incidence of abortion and retained placenta but higher incidence of SB. This is probably due to the fact that the uterus of a primiparous cow has steadier ligaments and thus better ability to keep the foetus and expel the placenta after parturition but primiparous cows also have smaller pelvic dimensions that can lead to more SB at the end of lactation. López de Maturana et al. (2007) noticed that it is important to keep calving difficulties under control, especially in primiparous cows and to escape reduction of profitability in herds. Diseases, such as mastitis, metritis and retained placenta may negatively influence the reproductive performance in dairy cows (Rajala-Schultz and Gröhn 1998; Huszenicza et al. 2005; Isobe et al. 2014). Mastitis is a multifaceted and expensive disease of dairy ACTA VET. BRNO 2017, 86: 345–352; https://doi.org/10.2754/avb201786040345 Address for correspondence: Judita Zymantiene Department of Anatomy and Physiology Faculty of Veterinary Medicine Lithuanian University of Health Sciences Tilzes st. 18, LT-47181, Kaunas, Lithuania Phone: +370 37 363 204 W-mail: judita.zymantiene@lsmuni.lt http://actavet.vfu. cz/ cows, which significantly reduces the milk production and performance of the dairy sector. Mdegela et al. (2009) estimated that subclinical mastitis is economically more important than clinical mastitis. Subclinical mastitis is more difficult to detect and eventually causes more production losses. Schrick et al. (2001) reported that negative consequences of mastitis on the reproductive efficiency of dairy cows are not limited to its clinical form but are also observed when the disease is at its subclinical stage. Hawari and Dabbas (2008) noticed that infectious agents commonly associated with mastitis in dairy cows are Streptococcus agalactiae and Staphylococcus aureus. Gitau et al. (2011) estimated that coliform bacteria and environmental streptococci are commonly found in the cows’ environment as well. Gilbert et al. (2005) found that mastitis may influence the pattern of hormonal secretion and follicular development, due to the release of substances that inhibit the expression of receptors for gonadotropins and other reproduction-related hormones. In cases of mastitis caused by gram-negative bacteria, other reproductive disorders may occur, such as reduced oestrus expression and irregular cyclicity (Huszenicza et al. 2005; Dobson et al. 2007). Studies by Valde et al. (1997) and Washburn et al. (2002) have demonstrated unfavourable relationships of the negative energy balance, related metabolic disorders with reproductive performance and mastitis in high-producing postpartum dairy cows. Postpartum dairy cows undergo a marked change in the energy status as their normal ovarian cycles are restored. Dairy cattle undergo a period of negative energy status in early lactation because the energy output for milk production exceeds the energy intake from feed (Risco 2004). Dystocia with the calving related disorder can aggravate the negative energy status of cows during the postpartum period. Successful management of lactating dairy cows needs to integrate the programs of reproduction and herd health, to optimize both milk, health and reproductive performance. The objective of this study was to determine the relationship between dystocia and SB and the prevalence of mastitis in dairy cows in order to expand the current knowledge on mastitis aetiology as a result of interactions between a combination of microbiological factors and management practices of herd reproduction. Materials and Methods The research was carried out at the Laboratory of Establishment of Animal Breeding Value and Selection of Lithuanian University of Health Sciences. Records of stillbirths (SB) and calving ease (CE) were obtained from the Centre of State Rural Business Development. The study was conducted in two stages. In the first stage, the calving scores and SB were analysed in 559 304 Lithuanian Black and White cows. Each cow was assigned a dystocia score based on CE. Calving ease was determined using the following scoring: score 1 – “no problemˮ, score 2 – “slight problemsˮ, score 3 – “cow needs assistanceˮ, score 4 – “considerable forceˮ used to deliver calf and score 5 – “extremely difficult birthˮ. Still birth was definied as a calf born dead or a calf that died within 24 h after birth. In the second stage, the cows were selected for evaluation of the somatic cell count (SCC) in milk, detection of microbiological udder health status after determination of CE scores, and detection of SB. Somatic cell count in milk as well as microbiological udder health status were evaluated in 1498 cows between 4–8 weeks postpartum. The SCC was determined using Somascope (CA-3A4, Delta Instruments, the Netherlands), which operates on the principle of flow cytometry technology, and was carried out at the State Laboratory for Milk Control, which operates under the requirements of ISO/IEC 17025:2005 to ensure the accuracy of milk composition and quality tests. Before milking, milk samples were collected aseptically for microbiological culture. The microbiological testing of milk samples from cows was performed at the State Laboratory for Milk Control, according to the standards of the National Mastitis Council (Harmon 1994). Statistical analysis Statistical procedures included descriptive statistics (mean ± standard error), Pearson’s correlation, linear regression and χ2 test were calculated by SPSS Version 15.0 for Windows and Student’s t-test was performed in order to detect significant differences between compared groups. The results were considered significant at P ≤ 0.05. 346