The Impacts of Protein Supplementation and Semen Exposure on Uterine Cytokines in Beef Heifers

doi:10.21203/rs.3.rs-3338166/v1

Download PDF

Short Report

The Impacts of Protein Supplementation and Semen Exposure on Uterine Cytokines in Beef Heifers

https://doi.org/10.21203/rs.3.rs-3338166/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Reproductive efficiency is largely impacted during heifer development which generally requires nutrient supplementation for proper maturation. Nutritional status can also influence inflammation within the reproductive tract. Therefore, we hypothesized that cytokine concentrations in uterine luminal fluid (ULF) will be impacted by protein supplementation following artificial insemination (AI). Commercial heifers (n = 60) were utilized to determine the effects of protein supplementation and AI on cytokine concentrations in ULF. Heifers were randomly assigned to one of three supplemental treatments: 1) CON (10% crude protein [CP]), 2) P20 (20% CP), and 3) P40 (40% CP). All heifers underwent estrus synchronization and ULF was collected 14 d after insemination. Cytokine profiles were constructed in MetaboAnalyst 5.0 and R Studio was used for individual cytokine analyses. Control heifers had increased (P = 0.05) MIP-1β concentrations (148.7 ± 123.9pg) over P20 heifers (42.3 ± 123.9pg) and P40 heifers (75.5 ± 123.9pg) were intermediate. Semen exposure (1877 ± 550pg) tended (P = 0.06) to increase concentrations of IP-10 compared with heifers who were not inseminated (1556 ± 550pg). In conclusion, protein supplementation and exposure to semen had a limited impact on the cytokine profiles and individual cytokine concentrations in the ULF of heifers following AI but did identify three cytokines providing potential targets important in early gestation.

Bovine

Cytokines

Inflammation

Protein Supplementation

Uterine Fluid

With the rapidly growing population, the beef industry must incorporate sustainable practices to provide enough nutrient-dense food even as land availability decreases (1, 2). Reproductive efficiency, and thus overall beef production, is impacted during the development of new breeding females. Heifer development is largely influenced by nutrition (3, 4) and if inadequate reproductive efficiency will decrease (5). Nutrient supplementation is generally required for the proper maturation of beef heifers. Heifers provided supplemental protein during development experience elevated growth and fertility rates compared to those without protein supplementation (6). However, overfeeding protein can delay the onset of puberty and reduce pregnancy rates (7–9). Recent studies have reported amino acids (AA) concentrations within uterine luminal fluid (ULF) throughout the estrous cycle (10) and early gestation (11–13). Concentrations of AA have been shown to increase during early gestation (11, 12) and are reduced in sub-fertile cattle (14). These data further implicate AA and protein concentrations on the successful establishment of pregnancy. Nutritional status can also influence immunological status (15). To prevent embryonic rejection, an immuno-tolerant uterine environment via cytokine signaling must be created to facilitate attachment (16). Cytokines impact a variety of reproductive and pregnancy-related processes like the estrous cycle (17), ovulation (18), embryonic development (19), and implantation (20). Therefore, identifying how nutrition, specifically protein, can influence inflammation within ULF could allow for alterations in management strategies to improve reproductive outcomes. Therefore, we hypothesized that cytokine and chemokine concentrations within the reproductive tract will be impacted by protein supplementation following insemination which may alter the establishment of pregnancy and embryonic development.

Experimental Design and Sample Collections

Commercial Angus heifers (n = 60) were utilized to determine the effects of protein supplementation on cytokine concentrations in ULF following estrus synchronization and artificial insemination (AI). All animal procedures and diets have been previously described in detail (21). Briefly, all heifers had ad-libitum access to native grass hay, trace mineral supplements, and water. Heifers were housed in three-acre pens with 5 heifers each resulting in four pens per treatment. Heifers were blocked by body weight into four weight classes (n = 15 heifers per class) and randomly assigned to one of three supplemental treatments: 1) CON, 10% crude protein (CP) supplement consisting of 100% corn, 2) P20 consisting of 25% corn and 75% dried distiller’s grains (DDGs), and 3) P40 consisting of 25% DDGs and 75% soybean meal. This resulted in diets of approximately 11%, 15%, and 19% overall CP for CON, P20, and P40 heifers, respectively. All heifers underwent a 7-Day CO-Synch + CIDR estrus synchronization protocol (22). Heifers received an initial 100 µg i.m. injection of GnRH (gonadorelin diacetate tetrahydrate, Cystorelin®, Boehrenger Ingleheim, Duluth, GA) and CIDR device (1.38 g progesterone; Zoetis Animal Health, Flor-ham Park, NJ) was inserted into the vagina for 7 days. Upon CIDR removal, heifers received an i.m. injection of 500 µg PGF2α (Cloprostenol sodium; Synchsure™, Boehrenger Ingleheim, Duluth, GA). Fixed-time AI was performed by a single technician beginning approximately 54 h after CIDR removal, concurrent with an i.m. injection of GnRH. At the time of breeding, one animal from each pen was randomly selected to not be inseminated to serve as a synchronized but unexposed control for cytokine analyses. Uterine luminal flush was collected 14 d after insemination by placing 20 mL of sterile saline into the vagina via insertion of a Foley catheter in the fornix vagina, mixed with vaginal fluid by rectal massage, removed through the catheter, and stored at -80ºC until cytokine quantification could be completed. Cytokine concentrations of IL-1α, IL-1β, IL-10, IL-17a, IL-36ra, IL-8, IL-4, IL-6, IP-10, TNF-α, IFN-γ, MCP-1, MIP-1α, MIP-1β, and VEGFa were quantified within ULF using the MILLIPLEX ® MAP Bovine Cytokine/Chemokine Magnetic Bead Panel (MilliporeSigma, Burlington, MA, USA) according to manufacturer protocol, and analyzed on the Luminex 200 system (Luminex, Austin, TX, USA) at the University of Tennessee Institute of Agriculture Genomics Hub.

Statistical Analyses

Cytokine profile analyses were completed with cytokine concentrations using MetaboAnalyst 5.0 (23) to identify differences in cytokine profiles within protein supplementation treatments and semen exposure. The chemometrics analysis using PLS-DA was utilized to evaluate cytokine profiles amongst all nutritional treatment and orthogonal PLS-DA was utilized to evaluate cytokine profiles between pairwise comparisons between protein treatments and semen exposure. Following cytokine profile analyses, individual ANOVAs were conducted to elucidate differences in individual cytokines. A randomized complete block design was implemented for individual statistical analyses in R Studio with pen as the experimental unit and heifers as the sampling unit. One-way ANOVAs were performed via the aov function with fixed effects of protein supplementation treatments and semen exposure. Fisher’s LSD was utilized for mean separation. Means were reported different when P < 0.05 and tendencies at P < 0.10.

There were no differences (P > 0.10) in cytokine profiles, via PLS-DA, amongst all three nutritional supplements (Fig. 1A). There were also no differences (P > 0.10) in cytokine profiles from orthogonal PLS-DA, from the pairwise comparisons of protein supplementation, CON vs P20 (Fig. 1B), CON vs P40 (Fig. 1C), and P20 vs P40 (Fig. 1D). Interestingly, the ellipses which represent the 95% confidence intervals of each profile were visual larger for heifers on the CON supplement compared with the P20 or P40 in both the 3-way and pairwise comparisons. There was no difference (P > 0.10) in cytokine profiles in ULF between heifers that underwent a synchronization protocol and were exposed to semen via AI compared with heifers that underwent a synchronization protocol but were not exposed to semen (Fig. 1E). Individual ANOVAs identified three cytokines, MIP-1β, IP-10, and MIP-1α, which were impacted by protein supplementation, semen exposure, and the interaction of protein supplementation 🞩 semen exposure. Heifers provided the CON supplement had increased (P = 0.05) concentrations of MIP-1β (148.7 ± 123.9 pg) compared with heifers fed the P20 supplement (42.3 ± 123.9 pg) and heifers fed the P40 supplement (75.5 ± 123.9 pg) were intermediate (Fig. 2A). Exposure to semen (1877 ± 550 pg) tended (P = 0.06) increase concentrations of IP-10 compared with heifers who were not inseminated (1556 ± 550 pg; Fig. 2B). Concentrations of MIP-1α tended (P = 0.07) to be influenced by an interaction of protein supplementation 🞩 semen exposure (Fig. 3). Heifer who received the CON and P20 supplements (70.9 ± 127.2 pg and 63.5 ± 127.2 pg, respectively) and were not inseminated were similar to heifers who were fed the P20 and P40 supplements (112.9 ± 127.2 pg and 120.3 ± 127.2 pg, respectively) but were inseminated. Heifers on the CON diet and inseminated (220.7 ± 127.2 pg) and heifers fed the P40 supplement and not inseminated (232.7 ± 127.2 pg) were similar to each other but tended to be greater than the other groups (Fig. 3).

These data are part of a larger study in which both cytokines and AA were analyzed during the development and through the breeding of these heifers (21, 24). Interestingly, the AA and cytokines were different throughout development but with limited impacts of supplemental protein (21, 24). The current dataset follows a similar trend with limited impacts of protein supplementation on cytokines following synchronization and AI. This is potentially due to the minor overall dietary differences that were created by these treatments (overall CP ranged from 11–19%) or the capacity of the rumen to supply CP when adequate levels of feed are provided. However, the two cytokines, MIP-1α and MIP-1β, were influenced by the interaction of protein supplementation and semen exposure or protein supplementation level alone. Recent research has reported a fluctuation in systemic and reproductive tract cytokines throughout the estrous cycle (17, 24–27), including MIP-1α and MIP-1β. These cytokines, MIP-1α and MIP-1β, were also found to increase in the uterus during heifer development as the heifer approaches the first breeding season (24). Vaginal cytokines were reported greatest during estrus regardless of if that estrus was from synchronization or natural estrus (26). Macrophage Inflammatory Protein-1α exhibited an interactive effect of protein supplementation level and semen exposure which may be indicative of a return to estrus in the not-exposed P40 heifers or a failure to conceive in the exposed group CON heifers. However, this effect requires more research to be completely elucidated. Macrophage Inflammatory Protein-1β is highly homologous, 60% (28), to MIP-1α. Interestingly, MIP-1β was only impacted by protein supplementation in the current study. In previous work, MIP-1β was shown to have a relationship with progesterone concentrations (24) which may explain the lack of an interactive effect in the current dataset since all of the heifers, regardless of exposure to semen, should have had a functional corpus luteum. However, protein supplementation did not impact MIP-1β during heifer development (24). This may indicate that protein supplementation following synchronization can alter the inflammatory status of the reproductive tract in preparation for embryo attachment and the establishment of pregnancy. However, more research needs to be conducted to further understand the impacts of protein, inflammation via MIP-1β, and successful pregnancy.

Interferon gamma-induced protein-10 is released from T lymphocytes, neutrophils, monocytes, splenocytes, endothelial cells, and fibroblasts (29, 30) to stimulate an inflammatory response as a chemoattractant. This classical function could explain the results in the current dataset as the inseminated heifers work to clear spermatozoa out of the uterus. However, IP-10 was reported to decrease between d 7 and 8 following breeding. This potentially contradicts the current data as current samples were taken 14 d after insemination, indicating IP-10 has another role during the establishment of gestation; this idea is supported by data in abortion-prone mice which had decreased concentrations of IP-10 (31). Murine models have reported an important role of both IFNγ and IP-10 (32) and inflammation in general early in gestation (31). However, most inflammatory cytokines, except IP-10, in the current dataset were not influenced by insemination. Since cytokine concentrations can fluctuate quickly, the lack of differences may be explained by the timing of sample collection, especially with other data reporting correlations between IP-10 and IFNγ, MIP-1β, and TNF-α during early gestation (27). More research to elucidate the exact function of inflammation and IP-10 during early pregnancy is required to understand the importance of this in bovine gestation.

Recent work in the area of cytokine profiles and inflammatory status within several reproductive fluids of cattle has shown limited impacts of global nutritional, supplemental nutrition, BCS, growth rate, or early gestation on cytokine profiles (24, 26, 27, 33). However, there were distinct cytokine profiles based on type of mating, AI vs natural service (26) further emphasizing the complexity of the interaction between nutrition, immunology, and reproductive function. This trend continued in the current dataset with no differences in cytokine profiles between protein supplementation and exposure to semen. Interestingly, our lab and others have identified multiple cytokines, -IL-1β, IL-8, MIP-1β, TNFα, VEGFa, and IFNγ, that are consistently differentially present in seminal plasma, ULF, blood samples, and vaginal fluid which may impact the reproductive environment and subsequent pregnancy outcome (17, 24–27, 33). Inflammation early in gestation has been reported to be important during the establishment of pregnancy and embryonic development in mice (31, 34), humans (34, 35), sheep (36), and with the growing body of literature most likely cattle. Nonetheless, more research needs to be conducted to understand the importance and timing of inflammation during early embryonic development and the establishment of gestation.

In conclusion, protein supplementation and exposure to semen had a limited impact on the cytokine profiles and individual cytokine concentrations in the ULF of heifers following AI. These data did identify three cytokines that were influenced by protein supplementation and exposure to semen providing a target pathway to continue to build the body of literature in the elucidation of the mechanisms and pathways vital to embryonic development and early gestation through the development of a non-hostile uterine environment.

Limitations

The major limitation of this study is the limited number of animals that were utilized in the not-inseminated category; only 1 per pen and 4 per treatment. Statistical power could have been increased had supplementation been provided individually, making heifer the experimental unit. However, this was not possible using current facilities available.

Amino Acids

Artificial Insemination

ANOVA

Analysis of Variance

BCS

Body Condition Score

CIDR

Control Internal Drug Release

CON

Control Supplement of 10% Crude Protein

Crude Protein

DDGs

Dried Distillers Grains

GnRH

Gonadotrophin Releasing Hormone

IFN

Interferon

Interleukin

i.m.

intramuscular

Interferon γ-induced Protein

LSD

Least Squares Difference

MCP

Monocyte Chemoattractant Protein

MIP

Macrophage Inflammatory Protein

P20

Treatment Supplement of 20% Crude Protein

P40

Treatment Supplement of 40% Crude Protein

PGF2α

Prostaglandin – F2α

PLS-DA

Partial Least Squares-Discriminant Analysis

TNF

Tumor Necrosis Factor

ULF

Uterine Luminal Fluid

VEGF

Vascular Endothelial Growth Factor

Ethics approval and consent to participate:

This study was carried out in accordance with the recommendations of the Institutional Animal Care and Use Committee at the University of Tennessee, Knoxville. The protocol was approved by the University of Tennessee, Knoxville Institutional Animal Care and Use Committee protocol number 2649–1018.

Consent for publication:

Not applicable

Availability of data and materials:

Data is available upon request from the corresponding author.

Competing interests:

The authors declare that they have no competing interests.

Funding:

This work was funded by the University of Tennessee Institute of Agriculture, the University of Tennessee Department of Animal Science, and the United States Department of Agriculture, National Institute of Food and Agriculture, Capacity Grant No. 1019048.

Authors’ contributions

KJM contributed to experimental design, data acquisition, analyses, interpretation of data, and manuscript preparation. KJB contributed to data acquisition, sample analyses, data interpretation, and manuscript preparation. TBAS contributed to data acquisition, sample analyses, data interpretation, and manuscript preparation. RRP, LGS, JLE, PRM, and JDR contributed to data interpretation and manuscript edits.

Corresponding author

Dr. Kyle J. McLean

Acknowledgments

The authors would like to thank Kevin Thompson and the Middle Tennessee Research and Education Center for help in collecting samples and providing care of the animals used in the study, and Dr. Neal Schrick for his advice on experimental design and uterine flush techniques. Additionally, the authors would like to thank the state of Tennessee through UT AgResearch, the Department of Animal Science, and the USDA National Institute of Food and Agriculture, Hatch Project No. 1019048 for providing funding and support for this research.

Elliot I. Meat output must double by 2050. Feedstuffs. http://feedstuffsfoodlink.com/story-meat-output-must-double-by-2050-71-66920. Accessed 1/15/2013.
Reynolds, L. P., M. C. Wulster-Radcliffe, D. K. Aaron, and T. A. Davis. 2015. Importance of animals in agricultural sustainability and food security. J. Nutr. 145:1377-1379. doi:10.3945/jn.115.212217.
Freetly, H. C., L. A. Kuehn, and L. V. Cundiff. 2011. Growth curves of crossbred cows sired by Hereford, Angus, Belgian Blue, Brahman, Boran, and Tuli bulls, and the fraction of mature body weight and height at puberty. J. Anim. Sci. 89:2373-2379. doi:10.2527/jas.2011-3847
Perry, G. A. 2016. Factors affecting puberty in replacement beef heifers. Theriogenology 86:373-378. doi: 10.1016/j.theriogenology.2016.04.051
Short, R. E., R. A. Bellows, R. Staigmiller, J. Berardinelli, and E. Custer. 1990. Physiological mechanisms controlling anestrus and infertility in postpartum beef cattle. J. Anim. Sci. 68:799-816. doi:10.2527/1990.683799x.
Short, R. E., and R. A. Bellows. 1971. Relationships among weight gains, age at puberty and reproductive performance in heifers. J. Anim. Sci. 32:127-131. doi:10.2527/jas1971.321127x.
Ferrell, C. L. 1982. Effects of postweaning rate of gain on onset of puberty and productive performance of heifers of different breeds. J. Anim. Sci. 55:1272-1283. doi:10.2527/jas1982.5561272x.
Lalman, D. L., M. K. Petersen, R. P. Ansotegui, M. W. Tess, C. K. Clark, and J. S. Wiley. 1993. The effects of ruminally undegradable protein, propionic acid, and monensin on puberty and pregnancy in beef heifers. J. Anim Sci. 71:2843-2852. doi:10.2527/1993.71112843x.
Kane, K. K., D. E. Hawkins, G. D. Pulsipher, D. J. Denniston, C. R. Krehbiel, M. G. Thomas, M. K. Petersen, D. M. Hallford, M. D. Remmenga, A. J. Roberts and D. H. Keisler. 2004. Effect of increasing levels of undegradable intake protein on metabolic and endocrine factors in estrous cycling beef heifers. J. Anim. Sci. 82:283-291. doi:10.2527/2004.821283x.
Hugentobler, S. A., M. G. Diskin, H. J. Leese, P. G. Humpherson, T. Watson, J. M. Sreenan, and D. G. Morris. 2007. Amino acids in oviduct and uterine fluid and blood plasma during the estrous cycle in the bovine. Mol. Reprod. Dev. 74:445-454. doi:10.1002/mrd.20607.
Groebner, A. E., I. Rubio-Aliaga, K. Schulke, H. D. Reichenbach, H. Daniel, E. Wolf, H. H. Meyer, and S. E. Ulbrich. 2011. Increase of essential amino acids in the bovine uterine lumen during preimplantation development. Reproduction 141:685-695. doi:10.1530/REP-10-0533.
Forde, N., C. A. Simintiras, R. Sturmey, S. Mamo, A. K. Kelly, T. E. Spencer, F. W. Bazer, and P. Lonergan. 2014. Amino acids in the uterine luminal fluid reflects the temporal changes in transporter expression in the endometrium and conceptus during early pregnancy in cattle. PLoS One 9:e100010. doi:10.1371/journal.pone.0100010.
Crouse, M. S., N. P. Greseth, K. J. McLean, M. R. Crosswhite, N. N. Pereira, A. K. Ward, L. P. Reynolds, C. R. Dahlen, B. W. Neville, P. P. Borowicz, and J. S. Caton. 2019. Maternal nutrition and stage of early pregnancy in beef heifers: impacts on hexose and AA concentrations in maternal and fetal fluids. J. Anim. Sci. 97:1296-1316. doi:10.1093/jas/skz013
Meier, S., M. D. Mitchell, C. G. Walker, J. R. Roche, and G. A. Verkerk. 2014. Amino acid concentrations in uterine fluid during early pregnancy differ in fertile and subfertile dairy cow strains. J. Dairy Sci. 97:1364-1376. doi:10.3168/jds.2013-6954.
Chandra, R. K. 1997. Nutrition and the immune system: an introduction. Am. J. Clin. Nutr. 66(2):460S-463S. doi:10.1093/ajcn/66.2.460S
Schjenken, J. E., J. M. Tolosa, J. W. Paul, V. L. Clifton, and R. J. Smith. 2012. Mechanisms of maternal immune tolerance during pregnancy. Recent Advances in Research on the Human Placenta. 11:211-242.
Krakowski, L., and B. Zdzisinska. 2007. Selected cytokines and acute phase proteins in heifers during the ovarian cycle course and in different pregnancy periods. J Bulletin-Veterinary Institute in Pulawy 51:31.
Espey, L. L., A. S. Bellinger, and J. A. Healy. 2004. Chapter 9 - Ovulation: An inflammatory cascade of gene expression. In: P. C. K. Leung and E. Y. Adashi, editors, The Ovary (Second Edition). Academic Press, San Diego. 145-165.
Zolti, M., Z. Ben-Rafael, R. Meirom, M. Shemesh, D. Bider, S. Mashiach, and R. N. Apte. 1991. Cytokine involvement in oocytes and early embryos. Fertil. Steril. 56:265-272. doi:10.1016/s0015-0282(16)54483-5.
Simón, C., C. Moreno, J. Remohı́, and A. Pellicer. 1998. Cytokines and embryo implantation. J. Reprod. Immunol. 39:117-131. doi:10.1016/S0165-0378(98)00017-5.
Brandt, K. J., T. B. Ault-Seay, R. R. Payton, L. G. Schneider, J. L. Edwards, P. R. Myer, J. D. Rhinehart, and K. J. McLean. 2023. The impacts of supplemental protein during development on amino acid concentrations in the uterus and pregnancy outcomes of Angus heifers. Animals (Basel). 13:1995. doi:10.3390/ani13121995.
Geary, T., J. W. Pas, F. Thrift, and S. Dolezal. 1998. Effects of a timed insemination following synchronization of ovulation using the Ovsynch or CO-Synch protocol in beef cows. Prof. Anim. Sci. 14:217-220.
Pang, Z., Chong, J., Zhou, G., de Lima Morais, D. A., Chang, L., Barrette, M., Gauthier, C., Jacques, P. É., Li, S., and Xia, J. 2021. MetaboAnalyst 5.0: narrowing the gap between raw spectra and functional insights. Nucleic Acids Res. 49:W388–W396. doi:10.1093/nar/gkab382
Ault-Seay, T. B., T. D. Harrison, K. J. Brandt, R. R. Payton, L. G Schneider, P. R. Myer, J. D. Rhinehart, L. A. Rispoli, and K. J. McLean. 2021 The effects of protein level on cytokines and chemokines in the uterine environment of beef heifers during development. J. Anim. Sci. 99:skab105. doi:10.1093/jas/skab105
Oliveira, L. J., N. Mansourri-Attia, A. G. Fahey, J. Browne, N. Forde, J. F. Roche, P. Lonergan, and T. Fair. 2013. Characterization of the Th Profile of the Bovine Endometrium during the Oestrous Cycle and Early Pregnancy. PLoS ONE 8:e75571. doi:10.1371/journal.pone.0075571
McLean, K. J., T. B. Ault-Seay, and P. R. Myer. 2023. Changes in vaginal cytokines concentrations during artificial insemination and natural service in beef heifers. Research Square. doi:10.21203/rs.3.rs-3256625/v1
Dalton C. M. 2023. The effects of pregnancy status on vaginal cytokine profiles in lactating cows. University of Tennessee (Thesis).
Sherry, B. P. Tekamp-Olson, C. Gallegos, et al. 1988. Resolution of the two components of macrophage inflammatory protein 1, and cloning and characterization of one of those components, macrophage inflammatory protein 1 β. J Exp Med. 168:2251-2259.
Antonelli, A., S. M. Ferrari, D. Giuggioli, E. Ferrannini, C. Ferri, and P. Fallahi. 2014. Chemokine (C–X–C motif) ligand (CXCL)10 in autoimmune diseases. Autoimmunity Reviews 13(3):272-280. doi:10.1016/j.autrev.2013.10.010
Li, J., M. Ge, S. Lu, J. Shi, X. Li, M. Wang, J. Huang, Y. Shao, Z. Huang, J. Zhang, N. Nie, and Y. Zheng. 2017. Pro-inflammatory effects of the Th1 chemokine CXCL10 in acquired aplastic anaemia. Cytokine 94:45-51. doi:10.1016/j.cyto.2017.04.010
Jiang, Y., F. Huang, X. Chai, W. Yuan, H. Ding, and X. Wu. 2021. The role of IP-10 and its receptor CXCR3 in early pregnancy. Molecular Immunology 140:59-69. doi:10.1016/j.molimm.2021.09.013
Taft, R. A. 2008. Virtues and limitations of the preimplantation mouse embryo as a model system. Theriogenology 69(1):10-16. doi:10.1016/j.theriogenology.2007.09.032
Harrison, T. D., E. M. Chaney, K. J. Brandt, T. B. Ault-Seay, R. R. Payton, L. G. Schneider, L. G. Strickland, F. N. Schrick, and K. J. McLean. 2023. The effects of nutritional level and body condition score on cytokines in seminal plasma of beef bulls. Front. Anim. Sci. 3: 1078960. doi:10.3389/fanim.2022.1078960
Raghupathy, R. 1997. Th 1-type immunity is incompatible with successful pregnancy. Immunology Today 18:478-482. doi:10.1016/s0167-5699(97)01127-4
Wegmann, T. G., H. Lin, L. Guilbert, and T. R. Mosmann. 1993. Bidirectional cytokine interactions in the maternal-fetal relationship: is successful pregnancy a TH2 phenomenon? Immunology Today 14:353-356. doi:10.1016/0167-5699(93)90235-d
Asselin, E., G. A. Johnson, T. E. Spencer, F. W. Bazer. 2001. Monocyte chemotactic protein-1 and -2 messenger ribonucleic acids in the ovine uterus: regulation by pregnancy, progesterone, and interferon-tau. Biol. Reprod. 64:992-1000. doi:10.1095/biolreprod64.3.992

No competing interests reported.

Download PDF

Version 1

posted

You are reading this latest preprint version

The Impacts of Protein Supplementation and Semen Exposure on Uterine Cytokines in Beef Heifers

Status:

Version 1

Abstract

Figures

Introduction

Methods

Experimental Design and Sample Collections

Statistical Analyses

Results

Discussion

Limitations

Abbreviations

Declarations

Ethics approval and consent to participate:

Consent for publication:

Availability of data and materials:

Competing interests:

Funding:

Authors’ contributions

Corresponding author

Acknowledgments

References

Additional Declarations

Status:

Version 1