scholarly journals 372 The timing of pregnancy losses in beef cattle

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 123-124
Author(s):  
Ky G Pohler

Abstract Pregnancy loss in beef cattle causes both management and economic challenges to a producer. Recent studies have been conducted to quantify reproductive failures that occur during fertilization, early embryonic development, and late embryonic/early fetal development periods of gestation in beef cattle. Minimizing reproductive inefficiency, specifically embryonic mortality (EM), is vital. Although fertilization rates are reportedly high in beef cattle, significant developmental failure occurs within the first 7 days of gestation. Approximately 28.4% of embryos will not develop past day 7 of gestation with most embryonic losses occurring before day 4. By the conclusion of the first month of gestation, 47.9% of cows submitted to a single insemination at day 0 will not be pregnant. Overall, late embryonic/fetal development between days 32 to 60 and 100 is 5.8% with a range of 3.2 to 42.7%. This talk will highlight some of the work our group is focusing on to determine timing and detection of pregnancy loss during these pivotal periods of pregnancy loss and potential management aspects to mitigate reproductive inefficiency. This was supported by Agriculture and Food Research Initiative Competitive Grant no. 2017-67015-26457 from the USDA National Institute of Food and Agriculture.

2018 ◽  
Vol 285 (1891) ◽  
pp. 20181977 ◽  
Author(s):  
S. F. Ryan ◽  
N. L. Adamson ◽  
A. Aktipis ◽  
L. K. Andersen ◽  
R. Austin ◽  
...  

The power of citizen science to contribute to both science and society is gaining increased recognition, particularly in physics and biology. Although there is a long history of public engagement in agriculture and food science, the term ‘citizen science’ has rarely been applied to these efforts. Similarly, in the emerging field of citizen science, most new citizen science projects do not focus on food or agriculture. Here, we convened thought leaders from a broad range of fields related to citizen science, agriculture, and food science to highlight key opportunities for bridging these overlapping yet disconnected communities/fields and identify ways to leverage their respective strengths. Specifically, we show that (i) citizen science projects are addressing many grand challenges facing our food systems, as outlined by the United States National Institute of Food and Agriculture, as well as broader Sustainable Development Goals set by the United Nations Development Programme, (ii) there exist emerging opportunities and unique challenges for citizen science in agriculture/food research, and (iii) the greatest opportunities for the development of citizen science projects in agriculture and food science will be gained by using the existing infrastructure and tools of Extension programmes and through the engagement of urban communities. Further, we argue there is no better time to foster greater collaboration between these fields given the trend of shrinking Extension programmes, the increasing need to apply innovative solutions to address rising demands on agricultural systems, and the exponential growth of the field of citizen science.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 244-245
Author(s):  
Sydney T Reese ◽  
Kelsey Schubach ◽  
Alice Brandão ◽  
Sarah M West ◽  
Meaghan M O’Neil ◽  
...  

Abstract Embryonic mortality (EM) is a major factor limiting pregnancy rates in cattle and occurs early (< day 28) or late (≥ day 28) during gestation. However, causes and mechanisms associated with late EM remain unknown. Despite negative connotations related to pregnancy, prostaglandin F2α (PGF) is capable of being released by the bovine uterus between days 28 and 32 of gestation. Therefore, the objective was to evaluate differences in PGF release between cows with high circulating concentrations of pregnancy associated glycoproteins (PAG) vs low PAG following an oxytocin (OT) challenge. Increased concentrations of PAG are associated with pregnancy success. At day 29 of gestation, pregnant cows were divided into high (n = 10) and low (n = 10) PAG groups and received either 100 I. U. of oxytocin intramuscularly (OT) or saline (control). Blood samples were collected every 30 minutes beginning 1 hour before and continuing for 4 hours after treatment. Prostaglandin F2α metabolite (PGFM), progesterone (P4), estradiol (E2) and PAG concentrations were determined. Peak concentration of PGFM occurred 2 hours after OT injection (average high PAG group peak: 345.6 ± 73.6 pg/mL; low PAG group peak: 326.4 ± 61.4 pg/mL, P > 0.05) and returned to baseline levels by 4 hours. No correlations were observed between PAG and PGFM concentrations (P > 0.05). There was no difference in initial or final PGFM concentrations between high or low PAG groups and control animals (P > 0.05). Furthermore, there was no difference in P4 or E2 concentration between treatment and control animals (P > 0.05) despite a luteolytic release of PGF2α. In summary, cows with high vs low PAG concentrations at day 30 of gestation have a similar PGFM response to OT challenge. This project supported by Agriculture and Food Research Initiative Competitive Grant no. 2017-67015-26457 from USDA-NIFA.


2015 ◽  
Vol 27 (1) ◽  
pp. 123
Author(s):  
B. W. Daigneault ◽  
K. A. McNamara ◽  
P. H. Purdy ◽  
S. L. Rodriguez-Zas ◽  
R. L. Krisher ◽  
...  

Cryopreserved boar sperm is seldom used for AI because fertility is reduced. Despite many potential advantages of frozen-thawed sperm for AI, lack of reliable fertility estimation of frozen ejaculates before AI limits the application of frozen sperm. Conventional post-thaw evaluation of sperm does not accurately estimate fertility. Identifying sperm traits that predict fertility would help select ejaculates that produce adequate litter sizes. Our objective was to identify traits of cryopreserved sperm that are related to boar fertility for AI through the use of novel and traditional laboratory analyses. Semen from 14 boars of several breeds was cooled to 15°C for shipping before freezing. Post-thaw motility was evaluated using a microscope and confirmed with computer-automated sperm analysis. Sperm viability and acrosome integrity were measured at 0, 30, and 60 min post-thaw. In addition to traditional analyses, each sperm sample was tested by IVF to record fertilization, cleavage, and blastocyst development. A sperm-oviduct binding assay was used to compare the number of sperm bound to epithelial aggregates harvested from the isthmus. Additionally, a competitive zona binding assay using 2 distinct fluorophores for boar identification was used to count the number of sperm from each boar bound to the zona. Frozen sperm from the same ejaculates subjected to laboratory analyses were used to determine actual boar fertility. Fertility was measured by AI of mature gilts using 4.0 × 109 total sperm from one boar at 24 h and a second boar at 36 h after the onset of oestrus, and AI order was reversed in consecutive replicates. Fertility was expressed as the percentage of the litter sired by each boar. Reproductive tracts were harvested at 32 days after AI, and fetal paternity was identified using microsatellite markers. The actual boar fertility was regressed against the mean of each laboratory evaluation by boar, and the assays that best predicted fertility were identified using stepwise logistic regression. The model generated was highly predictive of fertility (P < 0.001, r2 = 0.87) and included 5 traits: acrosome compromised sperm (0 and 30 min), percent live sperm (0 min), percent total motility (30 min), and the number of zona bound sperm. An additional model in which fertility was assessed by the number of piglets sired by boar also predicted fertility (P < 0.05, r2 = 0.57) and shared many of the same traits. These models were highly accurate when used to predict actual fertility of cryopreserved boar sperm. This approach may be used to screen ejaculates before AI and advance the use of frozen boar sperm by the swine industry.Research was supported by Agriculture and Food Research Initiative Competitive Grant no. 2010-85112-20620 from the USDA National Institute of Food and Agriculture.


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