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Summary: Heat stress can have severe deleterious effects on embryo development and survival. The present study evaluated whether CSF2 can protect the developmental competence of the bovine embryo following exposure to a heat shock of 41°C at the zygote and morula stages. In the first experiment, putative zygotes and 2-cell embryos were assigned to receive either 10 ng/ml CSF2 or vehicle, and then cultured for 15 h at either 38.5°C or 41°C and then at 38.5°C until day 7.5. Heat shock reduced blastocyst development for embryos treated with vehicle but not for embryos cultured with CSF2. In the second experiment, day 5 embryos (morula) were treated with CSF2 or vehicle and then cultured for 15 h at either 38.5°C or 41°C and then at 38.5°C until day 7.5. Temperature treatment did not affect development to the blastocyst stage and there was no effect of CSF2 treatment or the interaction. Results indicate that CSF2 can reduce the deleterious effects of heat shock at the zygote or two-cell stage when the embryo is transcriptionally inactive. [ABSTRACT FROM AUTHOR]

This study aimed to identify the impact of supplementing rumen-protected methionine (RPM) during the periconceptional period on beef cows in their progeny. Evidence suggests that changes in maternal nutrition in the periconceptional period have effects during the postnatal growth phase in cattle. We hypothesized that feeding RPM during the periconceptional period would program bovine gestation to enhance progeny growth. A total of 114 beef cows were fed a roughage-based diet and randomized to receive corn gluten supplemented with 15 g of RPM (Smartamine M, Adisseo) or not (CON) from d -7 to +7 relative to artificial insemination (AI) with female sex-sorted semen. Pregnancy diagnoses were conducted using transrectal ultrason-ography 30 and 60 d after AI. Female calves (n = 34) remained with their dams until weaning. A month after weaning, calves were weighed every 14 d during an 8-mo period, and wither height (WH), body length (BL), and heart girth (HG) were measured. Dry matter intake (DMI), average daily gain (ADG), and residual feed intake (RFI) were measured during a 56-d performance test. At the end of the performance test, the 12th rib back fat (BF), ribeye area (REA), intramuscular fat (IMF), and rump fat (RF) were determined via ultrasound. A treatment-by-day interaction tendency (P = 0.10) was observed in HG, having larger HG in the RPM treatment from d 336-adj of age (CON = 154.52 ± 1.46 cm; RPM = 158.36 ± 1.34 cm). During the performance test, animals in the RPM treatment were heavier (CON = 437.25 ± 2.46 kg; RPM = 442.79 ± 2.34 kg; P = 0.01) at the end of the test. However, no treatment difference (P > 0.05) was observed in DMI (CON = 12.06 ± 0.19 kg/d; RPM = 12.14 ± 0.18 kg/d), ADG (CON = 1.50 ± 0.03 kg; RPM = 1.55 ± 0.03 kg) and RFI (CON = -0.12 ± 0.15; RPM = 0.11 ± 0.14). No treatment difference (P > 0.05) was observed in BF, REA, and IMF. However, RF was greater in the control treatment (CON = 1.16 ± 0.07 cm; RPM = 0.91 ± 0.06 cm), and a tendency of having a thicker BF in control was observed (Table 1). In conclusion, supplementing RPM enhanced final body weight during the performance test; furthermore, a treatment-by-day interaction tendency was observed in HG. On the contrary, CON progeny had more RF and a tendency to have a thicker BF. [ABSTRACT FROM AUTHOR]

In beef cattle, 40% of cows that display estrus do not remain pregnant after embryo transfer (ET). Estrus is a physiological behavior influenced by the concentration of sex-steroids. The use of accelerometer devices for estrus detection is a common practice in dairy operations. It remains unclear if this same artificial intelligence software can accurately measure reproductive behavior in beef females. We hypothesized that estrous variables detected by an accelerometer are associated with ovarian, hormonal, pregnancy outcome, and fertility-related variables measured in the cow. Fifty Bos indicus-influenced, cyclic, primiparous cows were fitted with an accelerometer collar (SCR Engineers, Israel) and a breeding indicator (Estrotectâ) to detect estrus after a synchronization protocol in five subsequent experimental replicates (n = 50*5 = 250). Only cows that showed estrus (d 0) remained in the study. The following variables were used from the accelerometer software: Activity Peak, Rumination Nadir, Estrus Duration, and Heat Index, calculated by proprietary algorithms. Dominant follicle (DF) diameter and plasma concentration of estradiol were measured on d -2 (day of progesterone device removal) and on d 0. On d -1 and d 4, endometrial thickness and luminal fluid accumulation were measured by ultrasonography. On d 7, two embryos were transferred/cow. Pregnancies were diagnosed on d 45 and terminated. After 30 d, a new replicate started. Cows included in at least two replicates that remained pregnant 100%, 99-50%, or less than 50% were classified as fertile, sub fertile, and infertile, respectively. Estrus display was recorded for 166 cows (66%). Estrus detection by accelerometer and Estrotect had excellent agreement rate (kappa coefficient 0.76). Cows detected in estrus only by Estrotect had 66% less pregnancy/ET than cows in estrus by both (9/21 vs. 97/145; P = 0.01). The DF diameter on d 0 was not associated with accelerometer variables. Cows with greater and moderate Activity Peak had a greater growth rate of the DF from d -2 to d 0 than lower Activity Peak cows (interaction day*Activity Peak; P = 0.06). Estradiol on d -1 was positively associated with the Activity Peak (P < 0.0001). Cows with lower Activity Peak had a thicker endometrium on both d -1 and d 4 (P=0.02), and greater uterine luminal fluid score on d -1 (P=0.03). Fertility status was not associated with any accelerometer variables. In conclusion, the Activity Peak is associated positively with estradiol concentration and DF growth, however no association was found with pregnancy outcome and fertility. Therefore, the main advantage of accelerometers in beef ranches is the ability to detect estrus at a similar accuracy as breeding indicators, using less labor. Future enhancements in hardware and software to allow prediction of pregnancy outcomes are expected to increase reproductive efficiency in cow-calf operations. [ABSTRACT FROM AUTHOR]

In beef cattle, for a single pregnancy opportunity, only 60% of cows will remain pregnant. It is possible that uterine dysfunction prevents adequate embryo signaling and subsequent placentation. Our aim was to compare the abundance of molecular markers associated with pregnancy retention among embryo recipients classified for fertility. The hypothesis was that expression of interferon-stimulated genes (ISG15 and RSAD2) in lymphocytes and concentration of pregnancy associated glycoproteins (PAGs) in serum increase according to cow fertility. Cyclic, Bos Indicus-influenced, primiparous cows (n = 50) were submitted to five consecutive rounds of estrus synchronization, embryo transfer (ET), pregnancy termination and recovery. The ET was conducted 7 days after estrus (D7). Each cow received two embryos per transfer from a randomly assigned bull pair (BP) containing one embryo from each bull A, B or C (BP1 = A+B; BP2 = A+C; BP3 = B+C). Pregnancy diagnostic was conducted on D32 and D45 using B-mode ultra-sonography. Blood samples were collected on D20 to quantify expression of ISG15 and RSAD2 in peripheral blood mononuclear cells and on D25, D32, and D39 to quantify serum concentration of PAGs. Based on D45 pregnancy outcome (pregnant or open), cows were classified as Fertile (Fert; n = 14), Sub-fertile (SF; n = 16) or Infertile (IF; n = 15) if they were pregnant 3, 2, or 1 out of the 5 experimental rounds, respectively. Five cows that never sustained a pregnancy until D45 were excluded. The overall prevalence of twin-pregnancies was 7.8% (n = 13/166). Expression of ISG15 was increased in Fert compared to IF cows (P = 0.01; 0.0196 ± 0.0042 vs 0.0164 ± 0.0052, respectively). There was no effect of fertility classification on the expression of RSAD2. Serum concentrations of PAGs increased over time (P < 0.0001), regardless of fertility classification (day x fertility classification; P > 0.4). There was an effect of BP on the probability of pregnancy on D32 and D45 (P < 0.05). For D32, BP2 (84%) was 3 times more likely to maintain a pregnancy than BP1 (52%), while BP3 (74%) was not significantly different. On D45, BP2 (80%) was 2.8 times more likely to remain pregnant than BP1 (50%), and BP3 (62%) was not different than either BP1 or BP2. The interaction bull pair by fertility classification on the probability of pregnancy on D45 approached significance (P = 0.1). While pregnancy to BP2 was similar across all fertility classifications (80%), pregnancy to BP1 decreased dramatically as classifications changed from Fert to IF (88% vs. 14%, respectively). In conclusion, IF cows were less able to respond to IFN-t, likely because of a reduced secretion of IFN-t from the elongating conceptus. Also, IF cows are more susceptible to the genetics of the embryo than FERT cows. [ABSTRACT FROM AUTHOR]

Previous evidence has suggested that fertilization and preimplantation embryonic development are sensitive periods that can be influenced by changes in maternal nutrition. We hypothesized that feeding rumen-protected methionine (RP-Met) during the periconceptional period will program bovine gestation in a manner that enhances fetal and postnatal growth. A total of 114 cows were fed a roughage-based diet and randomized to receive corn gluten supplemented with 15 g of RP-Met (RP-Met; Smartamine, Adisseo) or not (Con) from d -7 to +7 relative to artificial insemination (AI) with sex-sorted semen. Estrus synchronization was conducted using the 7-day CoSynch + CIDR protocol. Pregnancy diagnosis, embryo, and fetal morphology were conducted using transrectal ultrasonography 30, and 60 days after AI. After calving, 40 calves (Cont = 19; RP-Met = 21) were considered for birth weight (BW) analysis. Female calves (n=34) were weighed at 2 months of age. Pregnancy per AI at day 30 (Con = 50%, RP-Met = 55%) and day 60 (Con = 50%; RP-Met = 53.4%) were not different between groups (P ≥ 0.05). At 30 days of pregnancy, embryonic vesicle diameter (Con=11.0 ± 0.7 mm; RP-Met =11.6 ± 0.7 mm; P < 0.05) and circumference (Con=0.88 ± 0.09 cm2; RP-Met =0.99 ± 0.09 cm² P < 0.05) were larger in the RP-Met group but embryo length and abdominal cavity were not different between groups. No difference was observed in fetal morphology at d 60. A treatment by sex interaction was observed (P =0.04). Male calves (n=6) from cows fed RP-Met showed greater BW than those from Con group (Con=31.9 ± 2.3 kg; RP-Met =41.4 ± 2.3 kg) but no difference was observed in females (n=34). There was no difference in BW at 2 months of age between groups. In conclusion, using RP-Met increased embryonic vesicle diameter and circumference, and BW in males. [ABSTRACT FROM AUTHOR]

Changes in maternal nutrition during the periconceptional period can influence postnatal growth in cattle. This study aimed to identify the impact of supplementing beef cows with rumen-protected methionine (RP-Met) during the periconceptional period on their female progeny. In exp 1, plasma methionine (Met) levels were analyzed in samples from 10 Angus crossbred, non-lactating beef cows. Cows were randomly assigned to receive 454 g of cottonseed meal with 15 g/d of RP-Met (RPM; Smartamine M, Adisseo) or not (CON) for 5 d and data were analyzed as a completely randomized design with repeated measures. A treatment-by-day interaction was observed (P < 0.001), where plasma Met concentrations increased in the RPM treatment yet remained basal in CON. In exp 2, 114 cows were fed a roughage-based diet and randomized to receive 454 g/d of corn gluten supplemented with 15 g/d of RP-Met (RPM n = 56) or not (CON n = 58) from d -7 to 7 relative to timed artificial insemination (TAI) using sexed semen to obtain females. Amino acids were measured in plasma samples from d -8, 0, and 7 in cows. In the female progeny, body weight, withers height, body length, and heart girth were measured every 60 d from birth through weaning at an average age of 242 ± 5.8 d. Liver, adipose tissue, and longissimus dorsi muscle biopsies were collected at 187.88 ± 5.5 d of age and a subset of 20 random samples (CON = 10; RPM = 10) were selected for RNA-seq on each tissue. data were analyzed as a generalized randomized block design with repeated measures. Methionine was increased (P < 0.01) in plasma from cows in the RPM treatment on d 0 and 7. After calving, 34 female calves (CON = 16; RPM = 18) remained in the study and no difference was observed in birth weights between treatments. Calves were taller at the withers for RPM than CON (P = 0.03; CON = 92 ± 1.0 cm; RPM = 95 ± 1 cm) but there were no effects of treatment on other measures of body size. A total of 30, 24, and 2 differentially expressed genes (DEGs; P < 0.01) were observed in liver, longissimus dorsi muscle, and adipose tissue respectively. In summary, feeding RP-Met to cows in the periconceptional period resulted in female calves that were taller than CON before weaning. There were DEGs in the tissue samples but no other changes in measurements associated with body size. In conclusion, supplementation of RP-Met to beef cows during the periconceptional period caused minor changes in the female offspring before weaning., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

This study evaluated the effectiveness of genetic introgression of the SLICK1 allele derived from Senepol cattle into the Holstein breed to enhance thermotolerance. The SLICK1 allele, located in PRLR gene, confers a short and sleek coat that is inherited as a simple dominant phenotype. Approximately 40 years ago, the University of Florida initiated efforts to introgress this allele into the Holstein population. Here we tracked the introgression of the SLICK1 allele using a medium-density genotyping array and a reference population of both breeds (50 Holstein, 46 Senepol). Among the 31 SLICK1+ Holsteins, there was 15.25% ± 11.11% (mean ± SD) Senepol ancestry on BTA20. Holsteins at the University of Florida descended from slick matings that did not inherit the SLICK1 allele (n=9) exhibited no Senepol ancestry. A secondary introgression of Senepol genetics in SLICK1+ animals was found on BTA4, spanning 54 markers and 15 genes, with 26.67% Senepol ancestry. This region, previously linked to heat stress adaptation, suggests that the introgression extends beyond the SLICK1 allele to incorporate additional beneficial genetics for thermal stress adaptation. These findings indicate that deliberate introgression of the SLICK1 allele enhances specific traits and potentially introduces other adaptive genetic variations. The study demonstrates the successful use of genetic interventions to improve livestock resilience against environmental challenges without significantly disrupting the recipient breed's genetic structure. The introgression of the SLICK1 allele serves as a model for breeding programs aimed at optimizing animal welfare and productivity in the face of global climate change while maintaining breed integrity., (© The Author(s) 2024. Published by Oxford University Press on behalf of The American Genetic Association. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Choline is a known developmental programming agent of the bovine preimplantation embryo. Culture of the embryo with 1.8 mmol/L choline, a concentration much higher than in blood, alters development to cause increased weaning weight and other changes during the postnatal period. It was hypothesized here that choline exerts similar effects on the developmental program of the embryo when added at concentrations similar to those in peripheral blood (i.e., 4 mol/L). Oocytes were collected via ovum pick up and embryos were produced in vitro. Embryos were cultured until day 7 after fertilization in medium with 4 mol/L choline chloride, or, as a vehicle control, with an additional 4 mol/L sodium chloride. Blastocysts were transferred into recipients and pregnancy was diagnosed at approximately 28 d of gestation. Subsequent calves (n=37 for vehicle and n=35 for choline) were weighed at birth and at weaning. Addition of choline to culture medium did not affect the proportion of embryos that became blastocysts or the proportion of transferred blastocysts that produced a pregnancy. Birth weight was unaffected by treatment but calves derived from choline-treated embryos were heavier at time of weaning and gained more per day from birth until weaning than calves derived from embryos treated with vehicle. Results demonstrate that choline can act on the preimplantation embryo at a physiologically-relevant concentration to alter postnatal phenotype. Observations are further evidence for the importance of the first days of embryonic development for the phenotype of the resulting calf.

Choline is a vital micronutrient. In this study, we aimed to confirm, and expand on previous findings, how choline impacts embryos from the first 7 days of development to affect postnatal phenotype. Bos indicus embryos were cultured in a choline-free medium (termed vehicle) or medium supplemented with 1.8 mM choline. Blastocyst-stage embryos were transferred into crossbred recipients. Once born, calves were evaluated at birth, 94 days, 178 days, and at weaning (average age = 239 days). Following weaning, all calves were enrolled into a feed efficiency trial before being separated by sex, with males being slaughtered at ~580 days of age. Results confirm that exposure of 1.8 mM choline chloride during the first 7 days of development alters postnatal characteristics of the resultant calves. Calves of both sexes from choline-treated embryos were consistently heavier through weaning and males had heavier testes at 3 months of age. There were sex-dependent alterations in DNA methylation in whole blood caused by choline treatment. After weaning, feed efficiency was affected by an interaction with sex, with choline calves being more efficient for females and less efficient for males. Calves from choline-treated embryos were heavier, or tended to be heavier, than calves from vehicle embryos at all observations after weaning. Carcass weight was heavier for choline calves and the cross-sectional area of the longissimus thoracis muscle was increased by choline., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Embryo transfer in cattle and other species is a key reproductive technology to improve genetic merit. However, pregnancy loss after embryo transfer is still a major barrier to optimal utilization of the technology. Furthermore, the lack of a method to objectively quantify embryonic competence hinders investigations aimed at improving the competence of an embryo. Based on the knowledge that bovine embryos have an inherent molecular signature that determines their ability for pregnancy establishment which can result in distinct gene expression profiles, we have previously integrated transcriptomic data from independent experiments to identify eight genes capable of predicting embryo competence for survival with high accuracy. In this study, we developed a function for the R software containing a mathematical formula based on the model coefficients to yield an embryonic competence index (ECI) according to the expression of those eight critical genes. Application of the function to a gene expression dataset generates a quantitative ECI value for each embryo that can be employed in statistical analyses when performing an experiment. The folder with the R project and required datasets can be found in https://zenodo.org/records/12515587., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Global warming is a major challenge to the sustainable and humane production of food because of the increased risk of livestock to heat stress. Here, the example of the prolactin receptor ( PRLR ) gene is used to demonstrate how gene editing can increase the resistance of cattle to heat stress by the introduction of mutations conferring thermotolerance. Several cattle populations in South and Central America possess natural mutations in PRLR that result in affected animals having short hair and being thermotolerant. CRISPR/Cas9 technology was used to introduce variants of PRLR in two thermosensitive breeds of cattle - Angus and Jersey. Gene-edited animals exhibited superior ability to regulate vaginal temperature (heifers) and rectal temperature (bulls) compared to animals that were not gene-edited. Moreover, gene-edited animals exhibited superior growth characteristics and had larger scrotal circumference. There was no evidence for deleterious effects of the mutation on carcass characteristics or male reproductive function. These results indicate the potential for reducing heat stress in relevant environments to enhance cattle productivity., Competing Interests: Authors from Acceligen and Semex have an interest in commercialization of gene‐edited livestock. There are no other conflicts., (©2024 The Authors FASEB BioAdvances published by The Federation of American Societies for Experimental Biology.)

The objectives of the present study were to characterize the expression of genes encoding for cell signaling ligands in the bovine endosalpinx and endometrium and analyze spatial changes in gene expression. RNA sequencing was performed for the endosalpinx from the ampulla of the oviduct and endometrium from the upper and middle uterine horn and uterine body at day 2 after ovulation from ipsilateral and contralateral sides relative to the ovulatory ovary. Of the 17,827 unique mRNA transcripts mapped, 2,072 were affected by cranial-caudal position in the reproductive tract and 818 were affected by side (false discovery rate < 0.05). There were 334 genes encoding for cell signaling ligands, with 128 genes having greater than two transcripts per million on average. A total of 81 cell signaling ligand genes were affected by position and 24 were affected by side. A data set of the transcriptome of two to four cell embryos was used to identify cell signaling ligand genes that were highly expressed in the ampulla for which there was high expression of the receptor in the embryo. The most expressed ligand-receptor pairs were PSAP/SORT1 , MIF/CXCR4 , GPI/AMFR , and KITLG/KIT . These cell signaling ligands, as well as others whose gene is expressed in the endosalpinx and endometrium, may influence early embryonic development. Spatial changes throughout the reproductive tract highlight the distinctive expression profile of the oviduct versus the endometrium, including a set of the identified genes encoding for cell signaling ligands, and highlight the local influence of the ovary. The results also show the continuity of expression for large numbers of genes in the reproductive tract. NEW & NOTEWORTHY Examination of the transcriptome of the endosalpinx and endometrium revealed the degree to which gene expression in the reproductive tract varies spatially. The expression of genes encoding cell signaling molecules that could potentially regulate embryonic development was also identified.