Susana Astiz

Epizootic hemorrhagic disease (EHD) has emerged as a significant sanitary and economic challenge for cattle production in southwestern Spain. However, its impact on reproductive performance remains largely unknown. This longitudinal study evaluated the short- and long-term reproductive effects of EHDV serotype 8 infections in extensive beef cattle herds. A cohort of 63 breeding bulls and 504 suckler cows from 10 commercial farms in Western Spain was monitored across three consecutive reproductive seasons: pre-outbreak (2022–2023), outbreak (2023–2024), and post-outbreak (2024–2025). Seminal parameters (volume, sperm concentration, mass motility, individual motility, progressive individual motility, viability and abnormal sperm morphology) and female reproductive indices (calving interval, days open, and pregnancy loss) were compared across the different seasons using non-parametric methods, general linear mixed models, and logistic regression. Results showed a progressive deterioration in male seminal quality, highlighted by a significant decline in progressive and total motility extending into the post-outbreak season. Conversely, sperm concentration showed an acute drop associated to the severity of the EHD outbreak followed by a significant recovery. In females, frequency of reproductive disorders increased from 14.6% to 29.5% during the outbreak season, with increased stillbirth risk. Furthermore, a prolonged calving interval (median 380.0 vs. 361.5 days; P < 0.001) and increased days open (median 97.0 vs. 79.0 days; P < 0.001), were registered during the post-outbreak season. In conclusion, EHDV infection induces adverse reproductive effects in both bulls and cows extending well beyond the acute phase, representing a substantial economic threat to extensive beef systems.

Background: This study evaluated pelvic and perineal anatomical traits in dairy cows to determine whether morphological conformation is associated with urovagina (UV). The traits assessed were body condition score (BCS), caudal rump height (CRH), withers height (WH), coxal width (CW), ischial width (IW), rump length (RL), rump angle (RA), vulva angle (VA), vulvar commissure length (VL), vulvar commissure length below the caudal edge of the pelvic floor (VBPL), and its relative percentage (VBP%). A total of 1 445 cows were evaluated for the occurrence of UV, and 34 cases were identified. Morphometric traits were assessed in 1 038 lactating cows from 18 dairy farms in central Spain. Population means were calculated, and cows were classified into four groups according to RA: G1 (RA ≤ 0°), G2 (0° < RA ≤ 3°), G3 (3° < RA ≤ 8°), and G4 (RA > 8°), to evaluate associations between RA, the remaining morphometric traits, and UV. A cluster analysis was performed to identify morphological types, and the morphometric characteristics of the 34 cows diagnosed with UV were compared with those of cows without UV. Results: Overall, 22.6% of cows presented horizontal or elevated ischia (G1; RA ≤ 0°), considered a suboptimal pelvic conformation. The prevalence of UV was 2.35%. Compared with cows without UV, affected animals seemed to show a lower RA (3.32° ± 4.11 vs. 4.77° ± 4.37; P = 0.057), greater VA (119.76° ± 14.42 vs. 114.85° ± 13.08; P = 0.032), and lower VBP % (57.52 ± 18.47 vs. 72.96 ± 18.07; P = 0.0001). Cluster analysis identified four morphological groups: small–narrow, small–wide, tall–narrow, and tall–wide cows. Cluster 4 (tall–wide) exhibited the most horizontal RA (2.94° ± 4.2°; P < 0.0001). Conclusions: Dairy cows with a more horizontal or negative RA tend to have a lower VBP % and a greater VA, anatomical characteristics that were associated with UV in this study. These findings highlight the relevance of pelvic and perineal conformation as potential indicators of susceptibility to this condition.

Young calves are particularly vulnerable to environmental and nutritional challenges during early life, making feeding management an important factor influencing their welfare and development. This study evaluated the effects of feeding frequency and calcium gluconate supplementation on behavioural and physiological welfare indicators in 358 Holstein dairy calves reared under commercial conditions. Calves received 6 L of milk replacer per day distributed in either two or three meals and had ad libitum access to water and textured starter feed with or without calcium gluconate supplementation.Feeding frequency influenced several behavioural indicators. Calves fed three times daily showed more social interactions and fewer hunger-related behaviours than calves fed twice daily, despite receiving the same total milk allowance. Calcium gluconate supplementation was associated with subtle behavioural differences, although its effects were less pronounced. In contrast, neither feeding frequency nor gluconate supplementation significantly affected salivary cortisol or inflammatory biomarkers. Physiological responses were mainly influenced by sampling time and health status.These findings suggest that increasing feeding frequency may reduce feeding motivation and promote behavioural indicators consistent with a more positive affective state in dairy calves. The results also highlight the importance of combining behavioural and physiological measures when assessing calf welfare under commercial rearing conditions.

Microalgae may be adequate sources of polyunsaturated fatty acids (PUFA) for ruminants, but information regarding their dry matter (DM) digestibility is still scarce. The in vitro digestibility of various dried PUFA-rich microalgae for ruminants (Arthrospira platensis, Nannochloropsis gaditana, Scenedesmus almeriensis, Tetraselmis chuii, and Tisochrysis lutea) was evaluated and the ruminal biohydrogenation of their PUFA assessed. All microalgae had high content of ash (> 78.1 g kg^-1 DM), total nitrogen (> 66.3 g kg^-1 DM) and ether extract (> 122 g kg^-1 DM). The highest levels of α-linolenic acid (C18:3n-3), eicosapentaenoic acid (C20:5n-3), and docosahexaenoic acid (C22:6n-3) were found in S. almeriensis, N. gaditana, and T. lutea, respectively. Most PUFA of microalgae were extensively biohydrogenated by ruminal microorganisms, but biohydrogenation of C20:5n-3 in N. gaditana and C22:6n-3 in T. lutea was lower, suggesting that a substantial amount of these PUFA can escape the rumen unaffected. The in vitro total DM digestibility (TDMD) of microalgae was high (from 538 to 970 g kg^-1 DM). The proportion of DM digested in the rumen in relation to TDMD ranged from 49.3 to 64.5%, indicating that a considerable DM digestion occurred in the intestine. Therefore, the microalgae N. gaditana and T. lutea are efficient nutritional sources of bypass C20:5n-3 and C22:6n-3 fatty acids, respectively, for ruminants.

The influence of estrus and double ovulations of Holstein heifers on a 5d‐Co‐synch 72 h protocol during summer was explored. Cycling heifers on the 5d‐Co‐72 h synchronisation protocol were randomised to carry a progesterone device (116) from day 0 to day 5 of the synchronisation protocol or not (97), from them 100 and 84 underwent fixed‐time artificial insemination (FTAI). Another 70 heifers showed estrus before the first GnRH and were inseminated. Heifers were pregnant 34% (33/97) without device, 44.0% (51/116) with device and 44.3% (31/70) inseminated after estrus. Pregnancy per insemination (P/AI) tended to be higher (p = 0.059) inseminating after estrus than after FTAI without device. Three heifers without device and two with it showed double ovulation, four of which became pregnant. Pregnancy loss was similar among groups (0%–10%). P/AI was higher in heifers with estrus before FTAI (OR 13.96, p = 0.027), and with each additional day of age (OR 1.015; p = 0.015). The device was associated with higher progesterone on day 5, with more synchronised heifers, more ovulation frequency after first GnRH (96.6% vs. 84%, p = 0.007), and more heifers showing estrus before FTAI (96.0% vs. 85.7%, p = 0.018). Days to conception after first AI of the study, and after maximum three AIs were similar between synchronised groups, but significantly shorter in heifers inseminated after observed estrus. Fertility was higher in heifers that showed signs of estrus before accompanying the FTAI, while double ovulation seems not to be a major factor for fertility. An intravaginal device slightly improves efficiency under heat stress by increasing ovulation, progesterone, proportion of synchronised heifers and heifers showing estrus at AI.