PSIII-11 Impacts of late gestational in utero heat stress on small intestine dynamics of neonatal dairy calves
Bibliographic record
Abstract
Abstract Late gestation heat stress in dairy cows has been shown to negatively affect offspring growth and development. In utero heat stressed calves have altered small intestine morphology and an impaired ability to absorb colostral immunoglobulin G (IgG). Thus, the objective of this study was to characterize potential cellular and molecular alterations in the small intestine of neonatal in utero heat stressed calves. In the last ~56 d of gestation pregnant dams were either heat stressed (shade; n = 41) or cooled (shade, fans, soakers; n = 41) resulting in heifers that were in utero heat stressed (IUHS, n = 15) or in utero cooled (IUCL, n = 15). Heifers were fed 3.78 L of high-quality colostrum within 2 h of birth. Apparent efficiency of absorption (AEA) of IgG was calculated by measuring IgG content fed in colostrum and in 24 h serum. Within 4.6 ± 2.3 h of birth a subset of calves (n = 8/treatment) not fed colostrum were euthanized to collect samples from the ileum. Tissue for histological analysis was placed in 10% neutral buffered formalin before being dehydrated, embedded in paraffin, cut into 5 μm thicknesses, and mounted to glass slides. The TUNEL method was used to identify apoptotic cells using the Keyence BZ-X800 Microscope. Tissue for gene expression analysis was snap-frozen and kept at -80°C before RNA extraction and cDNA synthesis. The transcript abundance of endosomal (FCGRT, DAB2, MAMDC4), tight junction (ZO1, ZO2, ZO3, OCLN, CLDN1), and heat shock (HSP90, HSF1) related genes were measured by qPCR using the CFX96 Real-Time PCR detection System (BIO-RAD). Data were analyzed using PROC MIXED or PROC GLIMMIX depending on the response variable. TUNEL results are expressed as the proportion of positive cells to total cells. Quantitative PCR data were analyzed by assessing the estimates of the model relative to the geometric mean of 3 reference genes (ACTB, GADPH, RSP9; ΔΔCT). The concentration of colostrum IgG fed to calves was not different (136.1 vs. 122.5 g/L; IUHS vs. IUCL, respectively; P = 0.32), but AEA of IgG was reduced in IUHS relative to IUCL calves (23.5 vs. 33.3%; P < 0.01). The proportion of apoptotic cells within the villi of the ileum was increased in IUHS calves compared with IUCL (2.11 vs. 1.57%; P < 0.01). Ileum gene transcript abundance of DAB2 and MAMDC4 were increased (P < 0.01), while FCGRT transcripts tended to increase in IUHS calves (P = 0.08). All tight junction and heat shock-related gene transcripts were increased within the ileum of IUHS calves (P ≤ 0.02) with the exceptions of CLDN1 and HSP90, which were not different between treatments (P ≥ 0.22).These results suggest that exposure to heat stress in utero impact small intestine integrity after birth and affect key IgG transporters, providing insight into underlying mechanisms responsible for reduced IgG absorption in IUHS calves.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".