88 Association between the incidence of subclinical mastitis and embryonic/fetal loss in dairy cows at high-altitude conditions
J. F. Simbaña-Cifuentes A , M. A. Gutiérrez-Reinoso B C , V. C. Moreta-Cevallos A and M. Garcia-Herreros DA REPROBOVINE-Vet, Machachi, Ecuador
B Universidad Técnica de Cotopaxi, Latacunga, Ecuador
C Universidad de Concepción, Chillán, Chile
D Instituto Nacional de Investigação Agrária e Veterinária, Santarém, Portugal
Reproduction, Fertility and Development 35(2) 170-170 https://doi.org/10.1071/RDv35n2Ab88
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Subclinical mastitis is a prevalent disease that shortens the productive life of the affected cattle but there is little information related to the effects of subclinical mastitis on reproductive function in dairy cows. Thus, the main aim was to study the association between the incidence of subclinical mastitis and embryonic/fetal loss in dairy cows at high-altitude conditions. A total of 147 Holstein cows (age: ∼48 ± 12 months.; BW: ∼450 ± 50 kg; BCS: 3.0–3.5) located in Pichincha province, Ecuador (Köppen-Geiger: ET; coordinates: latitude: 0°21′2.77″N, longitude: 78°44′40.24″W; precipitation: ∼520 mm; relative humidity: ∼90%; M.T.: ∼13.2°C; altitude: ∼3,000 m.a.s.l.), were divided into three experimental groups on the basis of California mastitis test (CMT) scores and milk somatic cell counts (SCC; ×103/mL) performed after pregnancy confirmation (Day 30 post-AI) to determine the mastitis grade: Control (mastitis-free [MF] CMT: Negative homogenous mixture, no thickening; SCC: <100 × 103 cells/mL); Traces-Grade I ([TG1] CMT: Trace slight thickening that disappears immediately after mixing, but no tendency to form a gel; SCC: ≥100 × 103 and <200 × 103 cells/mL); and Grade II–Grade III group ([G2G3] CMT: Distinct slime formation occurs immediately after mixing, with a slight gel formation and the surface of the mixture becomes in consistent gel formation; SCC: ≥200 × 103 cells/mL). Moreover, subclinical mastitis was confirmed by isolating of known pathogens (microbiological culture) together with total bacterial count (TBC × cfu × 103/mL). Milk-derived parameters such as milk yield (MY; kg), fat milk (FM; %), and protein milk (PM; %) were scored from Day 0 to Day 150 post-AI. Embryonic/fetal loss (EFL; % conceptus absence or death) was scored from Day 30 to Day 150 post-AI by using ultrasonography. Chi-squared test, Spearman correlation, and multinomial logistic regression were performed using SPSS® version 25. A significant positive correlation was observed between mastitis grade and embryonic/fetal loss (ρ = 0.23; P = 0.01). There was a significant interaction between mastitis grade and embryonic/fetal loss as well (P = 0.016). Nonsignificant differences were observed among groups regarding milk-derived traits FM and PM (P > 0.05). However, significant differences were observed in SCC (75.0 ± 12.0 vs 150.0 ± 26.6 vs 524.6 ± 102.3; P < 0.05), TBC (25.6 ± 9.53 vs 36.5 ± 8.00 vs 48.3 ± 10.4; P < 0.05), and MY (15,110.9 ± 321.0 vs 13,798.9 ± 462.5 vs 11,819.7 ± 792.1; P < 0.05) traits when MF, TG1, and G2G3 groups were compared. Finally, the embryonic/fetal loss differed among groups (1/38 [2.63%] vs 8/53 [15.1%] vs 14/56 [25.0%] in MF, TG1, and G2G3, respectively; P < 0.05). In conclusion, an association between the grade of subclinical mastitis and the embryonic/fetal loss was observed in dairy cows during the first 150 days post-insemination. Other important traits, such as SCC, TBC, and MY, were affected. Finally, the interaction between subclinical mastitis grade and embryonic/fetal loss must be taken into account in order to avoid future pregnancy issues in dairy cows maintained at high-altitude conditions.
This research was supported by ANID 21201280.
