Publications by authors named "Perez-Villalobos N"

Sperm quality decreases over time, so bull semen may need to be preserved after field collection. However, the effect of handling such semen samples from commercial farms and placing them in very short-term storage has not been elucidated. Therefore, ejaculate from 25 bulls from 1 dairy and 14 beef cattle farms were collected under farm conditions and evaluated for semen quality during the first two hours after collection.

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Multiple ovulation and embryo transfer (MOET) systems have been intensively implemented in Japanese Black cattle in Japan and to create Japanese Black herds out of these areas. Environmental conditions influence MOET efficiency. Thus, we describe results of 137 in vivo, non-surgical embryo flushings performed between 2016-2020, in a full-blood Japanese Black herd kept in Spain and the possible effects of heat, year, bull, donor genetic value, and metabolic condition.

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CASA kinetic parameters are often evaluated in a diagnostic centre. How storage conditions affect ejaculates up to evaluation is unclear. We assessed, in 25 commercial bulls electroejaculated in the field, the impact of time until evaluation (0-2 h, 4-6 h, and 24 h post-ejaculation), holding temperature (5 °C vs.

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Seminal parameters can be evaluated in situ, or samples can be delivered to a diagnostic centre. How storage conditions affect ejaculates up to evaluation is unclear. We assessed, in 25 commercial bulls electroejaculated in the field, the impact of time until evaluation (0-2 h, 4-6 h, and 24 h post-ejaculation), holding temperature (5 °C vs.

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In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. We explored whether delaying the removal of the intravaginal progesterone device by 24 h in heifers synchronized with a 5d Co-synch 72-h protocol could improve reproductive efficiency of fixed-time artificial insemination (FTAI). In experiment 1, we examined the total synchronization rate (TSR) in cycling Holstein heifers.

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Researchers have contributed by increasing our understanding of the factors affecting reproduction in beef, mainly physical health and nutrition aspects, which have been main concerns during decades. Animal welfare is of outmost relevance in all animal production systems and it is strongly associated to stress. Stress responses involve endocrine, paracrine and neural systems and the consequences of this stress on the reproductive efficiency of specifically, beef cattle and bulls, need to be highlighted.

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The objective of this retrospective study was to investigate the prevalence of pregnancy loss (PL; between 28-110 pregnancy days) and its relationship with factors: farm, year (2015-2018), season, artificial insemination (AI)-rank, parity, AI-type (fixed-time vs. oestrus-AI), previous PL, days in milk (DIM), fixed-time-AI protocol, AI-technician, bull, and semen-type (sexed vs. conventional).

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Right displaced abomasum (RDA) and abomasal volvulus (AV) are common diseases in cattle. However, presently there is no consensus regarding the pathogenesis and nomenclature of the different positions that the abomasum can adopt in the right side of the cow. Therefore, the objective of this study was to describe the etiopathogenesis of the right displaced abomasum according to the description of the features observed in 268 cows with left displaced abomasum (LDA), which were rolled to induce the movement of the abomasum from the left side to the right (in fact, inducing an RDA in 44% of cases), to facilitate the surgical approach, and immediately surgically treated (abomasal omentopexy from the right side).

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We recorded conception rates and estimated pregnancy rates following second and later timed artificial inseminations (TAIs) after hormonal resynchronization on commercial dairy farms, using the so-called G6G protocol (PGF day-0; GnRH 2, 8 days; PGF 15, 16 days, GnRH 17 days; TAI 18 days), and the 5-day Ovsynch protocol or 5DO (GnRH day 0; PGF 5, 6 days; GnRH 7 days; TAI 8 days). In four farms, both protocols were implemented in parallel, and these 1,368 s and later TAIs were used for the protocols' comparison based on logistic regression (544 TAIs in primiparous; 824 in multiparous cows; 1,024 TAIs after G6G [600 TAIs in multiparous and 424 in primiparous]; 344 TAIs after 5DO [224 TAIs in multiparous and 120 in primiparous]; 280 TAIs during the hot season; 1,088 during the cool season). Conception rate (CR) was 31.

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A controlled field trial was conducted to assess the potential influence of practitioner inexperience during early pregnancy diagnosis with ultrasound (PD-US) on the risk of pregnancy loss. A veterinarian with more than 10 years' experience in PD-US (Vet-A) and a veterinarian with fewer than 12 months' experience at the start of the study (Vet-B) visited the same dairy farm once a week for 33 and 26 weeks, respectively. The two veterinarians did not interact with each other at any time during the study, nor did they know that their data would later be used in this study.

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Background: Bovine respiratory disease (BRD) is one of the leading causes of economic losses in the beef and dairy industry. Reliable antemortem tools for diagnosing BRD would improve the efficacy of treatment and reduce costs. Here we examined whether the relatively simple technique of thoracoscopy can support BRD diagnosis under field conditions.

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A blinded, negative controlled, randomized intervention study was undertaken to test the hypothesis that addition of meloxicam, a nonsteroidal anti-inflammatory drug, to antimicrobial treatment of mild to moderate clinical mastitis would improve fertility and reduce the risk of removal from the herd. Cows (n=509) from 61 herds in 8 regions (sites) in 6 European countries were enrolled. Following herd-owner diagnosis of mild to moderate clinical mastitis within the first 120 d of lactation in a single gland, the rectal temperature, milk appearance, and California Mastitis Test score were assessed.

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