141 EFFECT OF ENVIRONMENTAL TEMPERATURE ON EMBRYO PRODUCTION AND CONCEPTION RATES IN BEEF AND DAIRY CATTLE
Bibliographic record
Abstract
The aim of this study was to evaluate the effect of environmental temperature at the time of embryo collection and transfer on embryo quality and conception rates after transfer of fresh and frozen embryos. Purebred dairy (Holstein, Czech spotted cattle, n = 174) and beef (Charolais, Blonde d’Aquitaine, Piedmontese, Hereford, Limousin and Simmental; n = 72) donors were collected during 2005 to 2007. Donor cows received one application of PGF2a and superstimulation was initiated 9 to 11 days following estrus with pFSH (Folltropin-V; Bioniche Animal Health, Belleville, ON, Canada) given twice daily for 4 days. Prostaglandin2a was given on Day 3 of the superstimulation treatment. Donors were inseminated 3 times, with 1 unit of semen on Days 5 and 6 of treatment. Embryo recovery was carried out on Day 7 after insemination. The recipients were synchronized with PGF2a and embryos were transferred on Day 7 after estrus. The effect of temperature at the time of 246 embryo recoveries and 1338 transfers (fresh and frozen embryos) was analyzed using the GLM, assuming quasi-poisson and quasi-binomial error distribution by R software (www.r-project.org). We evaluated the total number of ova/embryos collected, embryo quality, and conception rates after transfer at the environmental temperatures shown below. Temperatures were divided into the following ranges: A) from –5 to 5°C; B) from 6 to 15°C; C) from 16 to 20°C; and D) over 20°C. The average temperature values were obtained from the Czech hydrometeorological institute and corresponded to the following seasons: winter (range A and B); spring (range B and C); summer (range C and D); fall (range C and B). Dairy cows were managed intensively in barns whereas beef cows were managed in barns during the winter and on pasture from April until October. In beef donors the mean number of total ova/embryos collected and transferable embryos were 9.1 ± 7.9 and 4.2 ± 4.5, respectively and no significant effect of temperature was detected (P > 0.05). In dairy donors the mean number of total ova/embryos collected and transferable embryos were 7.9 ± 6.0 and 4.9 ± 4.5, respectively and no significant effect of temperature was detected (P = 0.27). Conception rate was greatest (P < 0.001) in temperature range D (63.64%) compared with the other temperature ranges (A = 27.66%; B = 43.65%; C = 43.21%;) in beef cows and in the range C (65.31%) than in the other temperature ranges (A = 34.7%; B = 52.67%; D = 56.25%) in dairy cows. It was concluded that temperature at the time of embryo collection did not affect embryo production and quality. However, environmental temperature did have a significant effect on conception rates in both beef and dairy recipients. Nutritional status may also have contributed to the increased conception in beef cattle during warmer temperatures. However, the optimal period for conception in dairy cows was in temperature range from 16 to 20°C, because of the potential adverse effect of heat stress in high-yielding cows. Supported by MEYS CR MSM 2678846201, LA 330; NAZV 1B44034.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".