Elsevier

Theriogenology

Volume 159, 1 January 2021, Pages 87-97
Theriogenology

Farm and cow factors and their interactions on the incidence of retained placenta in holstein dairy cows

https://doi.org/10.1016/j.theriogenology.2020.10.007Get rights and content

Highlights

  • Risk factors for retained placenta (RP) with considering the interaction terms were identified.

  • Considering of interaction terms in a risk factor analysis was informative.

  • Probability of RP differs between herd, age at first calving, parities, dry period length, milk yield level and calving season.

  • Twinning increased the risk of RP in multiparous cows but not in primiparus cows.

  • An experience of dystocia and stillbirth increased the risk of RP for both multiparous and primiparus cows

Abstract

Risk factors for retained placenta (RP), as a common and economically important disorder, have been widely investigated. However, comprehensive studies are rare. Therefore, this study sought to identify herd-cow factors and their interactions on the risk of RP in Iranian dairy herds. The data were collected from nine Holstein dairy herds in Isfahan province, Iran. The final dataset included 154,048 records for 59,610 cows which calved between March 2011 and December 2018. A logistic regression model was used to separately analyze the risk factors and their interactions for RP in primiparous and multiparous cows. The average rate of RP was 12.3% (9.0–15.4%) at the herd level. The highest rate of RP was recorded in spring compared with other seasons. Regardless of calving season, occurrence of dystocia, stillbirth and twinning increased the odds ratio (OR) of RP. In primiparous cows, occurrence of dystocia and stillbirth increased OR of RP 4.30 and 3.33 times, respectively. In multiparous cows, dystocia, twinning and stillbirth increased OR of RP 4.36, 3.94 and 1.29 times, respectively. Cows with an age at first calving of >28 months had the highest rate of RP compared with other cows. Multiparous and primiparous cows with a short (less than 271 d) and long (more than 281 d) pregnancy, respectively, had the highest risk of RP compared to cows in other groups. Furthermore, multiparous cows with an extended dry period length (more than 75 d) and produced milk yield more than 13,000 kg/lactation were at higher risk of RP with an average of 13.5%. With an interaction analysis, although the potential effect of each factors depends on the effect of other factors, but in general dystocia, stillbirth, an extended age at first calving (>28 months), and calving during the spring increased risk of RP for both groups. In conclusion, identification of risk factors for RP with an interaction analysis can help farm managers to employ the best strategies to reduce the occurrence of this reproductive disorder.

Introduction

The process of parturition has been divided into three separate stages: 1) the dilation of the cervix, 2) the onset of myometrial contractions, and 3) the placement of the fetus for expulsion [25]. Given the importance of parturition, knowledge of factors around parturition and their economic importance are crucial issues in dairy farm management [11,31].

Retained placenta (RP) is one of the most common postpartum reproductive disorders. Since, this abnormality occurs during the transition period, it is also known as a metabolic disorder [10,20]. The fetal membranes are normally expelled within 8 h post-partum but are considered as retained if they are not expelled within 24 h of calf delivery. This is due to the failure of timely breakdown of the cotyledon-caruncle attachment [20].

The frequency of RP incidence varies across countries, herds and different parities within a herd. For instance, the incidence rate of RP in South Korea has been reported as 4.0–16.1% per calving [20], while in one study from the USA, 7.8% of dairy cows in different parity were affected by RP [18].

Based on the results from recent studies, many factors such as parity (Han and Kim, 2005), season of calving [17], dystocia, stillbirth, twinning [8] affect the incidence of RP. Moreover, the length of dry period [21], as well as pregnancy length [20] has been also associated with the incidence of RP. Higher milk yield [19] has also been associated with an increased the risk of RP. In addition to direct effect of above-mentioned factors, their interactions may also affect the incidence of RP in dairy cows.

The above studies have studied the factors influencing the incidence of RP in dairy cattle. However, thus far, most studies have examined only main effects without considering the interactions. Nevertheless, interactions play an important role in the study of factors affecting the incidence of disorders. Therefore, the objective of this study was to quantify the herd-cow level risk factors and their interactions on RP in Iranian Holstein cows. We used cow-herd level records collected from nine commercial dairy herds over an 8-year period.

Section snippets

Study herds

Data were collected from nine commercial dairy farms located in Isfahan province of Iran, for cows that calved between March 2011 and December 2018. Farms with herd size of >600 milking cows, and an accurate recording system were selected, with all farms under official performance and pedigree recording. All cows were raised in intensive production systems with free stall barns, fed a balanced total mixed ration, and milked 3 times per day. Although each herd had their own specific feeding and

Descriptive findings

Fig. 1 shows the eight-year trend of incidence of RP in primiparous, and multiparous cows as well as in all cows which calved during 2011–2018. In general, the incidence of RP in the studied herds had a decreasing trend that corresponded to a rate of −0.2% per year (Fig. 1). As shown in Fig. 1, the incidence of RP is higher in multiparous cows than in primiparous ones. During the study period, the incidence rate of RP reduced by 2.7%, and 1.5% for multiparous and primiparous cows, respectively.

Discussion

The average rate of RP incidence was 12.3% that varied from 9.0 to 15.4 across the studied herds. The incidence of RP for investigated herds showed a descending trend with a slope of −0.18 during 8-years study from 2011 to 2018. Dry period management in dairy cows is one of the effective factors on the occurrence of metabolic and reproductive diseases [32]. In the recent years, particular attentions have been paid to the use of fog lamps to reduce heat stress, density reduction and nutritional

Conclusion

The overall average of RP rate was 11.3% and declined between 2011 and 2018. Dystocia, twinning and stillbirth were identified as factors which had significant effects on the incidence of RP. The length of dry period and age at first calving (management factors) had significant effects on RP rate. Cows with extended dry period length (>75 d) and age at first calving (>28 months) had higher rate of RP. Furthermore, cows with a higher milk yield (>13,000 kg per lactation) had the highest risk for

Funding source

None.

CRediT authorship contribution statement

Abolfazl Mahnani: Conceptualization, Methodology, Software, Formal analysis, Investigation, Writing - original draft, Writing - review & editing, Project administration. Ali Sadeghi-Sefidmazgi: Conceptualization, Methodology, Software, Investigation, Validation, Formal analysis, Writing - review & editing, Supervision. Saeid Ansari-Mahyari: Validation, Supervision. Gholam-Reza Ghorbani: Validation, Supervision. Hamideh Keshavarzi: Methodology, Software, Validation, Formal analysis, Writing -

Acknowledgments

The authors of the article would like to thank the herd managers for collaborating and generously providing the information needed. Special thanks are extended to Peter Fennessy (AbacusBio Limited, Dunedin, New Zealand) for assistance in editing the manuscript.

References (36)

Cited by (0)

View full text