Theriogenology February 2021 - March 2020 Flashcards
Effect of dose and timing of prostaglandin F-2 alpha treatments during a 7-d Ovsynch protocol on progesterone concentration at the end of the protocol and pregnancy outcomes in lactating Holstein cows
Tippenhauer et al., 2021
A second PGF dose on d 8 during a 7-d Ovsynch protocol decreased percentage of cows with high progesterone (P4) concentrations at G2 and increased pregnancy per AI (P/AI) compared to a single PGF dose on d 7.
Doubling the PGF dose on d 7 in a 7-d Ovsynch protocol did not affect the percentage of cows with high P4 concentration at G2 and had only a marginal effect on P/AI compared to a single PGF dose on d 7.
There was no interaction between treatment and presence of a CL at G1 on P/AI.
Presynchronized cows receiving first postpartum TAI had similarly increased P/AI treated with a double PGF dose compared to treatment with a second PGF dos
Interaction of Mycobacterium avium subsp. paratuberculosis with bovine sperm
Caldeira et al., 2020
The adhesion of MAP on bovine sperm occurs mainly in the midpiece.
MAP affects the sperm parameters.
Interaction of MAP with sperm could be linked to the 85 complex proteins
- Sperm in the presence of MAP shows a decrease in motility and vigor, and that the higher the MAP concentration, the lower the sperm performance.
- It was possible to determine the viability of MAP after cryopreservation in samples of higher concentrations, which demonstrates the potential of transmission of this pathogen through artificial insemination.
- The interaction of MAP with bovine sperm occurs mainly in the midpiece and may be linked to the proteins 85A and 85B present in the MAP membrane
Feeding yearling Angus bulls low-level ergot daily for 9 weeks decreased serum prolactin concentrations and had subtle effects on sperm end points
Chohan et al., 2021
Ergot alkaloid feeding at 3.4 mg/kg of DMI/day for 9 weeks of yearling bulls transiently reduced plasma prolactin by 4-folds.
Body weight, scrotal circumference, rectal temperature, or sperm concentrations were not remarkably affected.
Subtle effects on progressive motility, mid-piece defects, and mitochondrial membrane potential were recorded.
Current Canadian ergot standards (3 mg/kg of feed) are adequate for bull reproduction; prolactin decrease is concerning.
Cow-level prevalence and risk factors for estrus detection inaccuracy in seasonal calving pasture-based dairy cows
Kelly et al., 2021 (Mc Aloon author)
The overall cow-level prevalence of estrous detection inaccuracy was low at 4.7%.
Estrous detection inaccuracy at first AI was lower than at repeat AI.
Lack of mounting abrasions were a risk factor for detection inaccuracy at first AI.
No observed standing estrus and an abnormal preceding repeat interval were risk factors for inaccuracy at repeat AI.
Changes in miRNA levels of sperm and small extracellular vesicles of seminal plasma are associated with transient scrotal heat stress in bulls
Alves et al., 2021
Scrotal heat stress (SHS) mainly down-regulates sperm miRNA levels.
SHS changes sEVs-associated-miRNAs involved in cell biosynthesis processes.
SHS changes miR-126-5p level in sperm and small extracellular vesicles.
miR-15a, −34b, −34c, −146a, −200b and −449a are potential spermatogenesis modulators.
Monitoring estrous activity in pasture-based dairy cows
Moore et al., 2021
Correlations between FlashMate(mount detector) and Moomonitor activity (accelerometer) during estrus were weak.
Fifty-five percent of cows received contacts related to mounting activity for ≤8 h.
Pregnancy rate reduced when cows were inseminated within 2–4 h of activity onset.
Maximising body condition score and days in milk at AI increased pregnancy rates
Characterization of intrauterine cultivable aerobic microbiota at the time of insemination in dairy cows with and without mild endometritis.
Ballas et al., 2021
High uterine bacterial diversity at the time of artificial insemination.
Bacillus, Staphylococcus, Corynebacterium, and Streptococcus the most common genera.
Rare detection of uterine pathogens, such as Trueperella pyogenes.
Mild endometritis at artificial insemination decreases the chance of pregnancy.
Intrauterine antibiotic treatment shortly after AI must be scrutinized
Bovine alphaherpesvirus 1 (BHV1) infection in testes and epididymis from bulls from a slaughterhouse
Queiroz-Castro et al., 2021
BHV1 was found in the reproductive tract of bulls by immunodetection and Nested-PCR.
We bring the first evidence of BHV1 presence in testes and epididymides of naturally infected bulls.
BHV1 in the testicle and in the epididymis may be sources of infection to the semen.
The effect of altering the timing of GnRH administration and artificial insemination in a modified 5-d CO-Synch protocol using sex-sorted semen in dairy heifers
Macmillan et al., 2021
Dairy heifers were subjected to a modified 5-d CO-Synch TAI protocol.
Giving GnRH 16 h before or at the time of AI did not affect P/AI.
Heifers in early estrus were AI 16 h earlier, tending to improve overall P/AI.
Delaying AI by 8 h increased estrus rates but did not improve P/AI.
Across both experiments, P/AI was increased in heifers that displayed estrus before AI compared with heifers that did not
Farm and cow factors and their interactions on the incidence of retained placenta in holstein dairy cows
Mahnani et al., 2021
Risk factors for retained placenta (RP) with considering the interaction terms were identified.
Considering of interaction terms in a risk factor analysis was informative.
Probability of RP differs between herd, age at first calving, parities, dry period length, milk yield level and calving season.
Twinning increased the risk of RP in multiparous cows but not in primiparus cows.
An experience of dystocia and stillbirth increased the risk of RP for both multiparous and primiparus cows
Changes in antioxidant enzyme activities and metabolic parameters in dairy cows during different reproductive periods
Sayiner et al., 2021
There is a significant relationship between the GPX enzyme activity and metabolic parameters in the postpartum period.
Could GPx’s significant rise in the early postpartum period be the messenger of metabolic diseases?
GPx and SOD are essential parameters as metabolic indicators in pre- and post partum period
Impact of assisted reproduction techniques on subsequent reproductive performance of dairy heifers and lactating cows
Figueiredo et al., 2020
Embryo donors had reduced hazard of first service and pregnancy linked to the time required for super stimulation protocols.
Ovum pick-up was associated with reduced pregnancy hazard in heifers and first lactation cows.
Fertility losses observed in Holstein donors were not associated with increased culling.
Evaluation of bovine sperm telomere length and association with semen quality
Ianuzzi et al., 2020
Sperm telomere length can be used as marker of bovine semen quality.
Sperm telomere length is correlated to most sperm quality traits.
Percoll density gradient separates sperm with longer telomeres
IFNT, ISGs, PPARs, RXRs and MUC1 in day 16 embryo and endometrium of repeat-breeder cows, with or without subclinical endometritis
Kasimanickam and Kasimanickam, 2020
ISGs, PPARs and RXRs were compared among normal and repeater breeder cows with or without subclinical endometritis.
ISG15, SLC2A1, CXCL10 and SLC27A6 were greater in endometrium of normal cows.
MUC1 was in greater in endometrium of repeat breeder cows with or without subclinical endometritis.
PPARD, PPARG, RXRA and RXRG were in greater in normal cows.
Gene network analysis showed interactions and pathways involving PPARD, PPARG, and MUC1.
Size and position of the reproductive tract impacts fertility outcomes and pregnancy losses in lactating dairy cows
Madureira et al., 2020
Lactating dairy cows with a larger reproductive tract have reduced P/AI and increased. Incidence of late embryonic mortality
Pregnancy associated glycoprotein concentrations on day 31 of gestation were reduced in. Cows with a larger reproductive tract
Larger reproductive tracts were more frequently observed in multiparous cows than primiparous cows
Cows with a larger reproductive tract were more likely to be culled from the herd
Chronological echocardiographic evaluation of left ventricular systolic and diastolic function in term and premature neonatal calves
Naseri et al., 2020
- Echocardiographic studies in human neonatology has demonstrated that prematurity can lead to cardiovascular dysfunction and especially compromises the left ventricular (LV) systolic and diastolic functions.
- There was LV diastolic dysfunction (55% premature calves, 10% term calf at day 1; 65% premature calves, 10% term calf at day 2 and, 75% premature calves, 20% term calf at day 3),
- LV systolic dysfunction deteriorated in both term and preterm calves (55% premature calves, 60% term calf at day 1; 55% premature calves, 50% term calf at day 2, and 45% premature calves, 40% term calf at day 3).
Echocardiography is a useful tool for evaluating cardiac functions and following heart development in neonatal animals
Influence of seasonal differences on semen quality and subsequent embryo development of Belgian Blue bulls
Sefi-Jamadi et al., 2020
Belgian Blue bulls are more susceptible to heat stress than most other cattle breeds.
Heat stress negatively affected the quality of Belgian Blue bulls’ spermatozoa.
Summer high ambient temperature increased H2O2 production in thawed spermatozoa.
Summer heat exposure increased morphological abnormalities of bull spermatozoa.
Embryo development was decreased after the bulls were exposed to summer heat stress
In summary, our data show that elevated ambient temperature and humidity during summer can decrease the quality of frozen-thawed spermatozoa in Belgian Blue bulls and also affect subsequent embryo developmen
Treatment with prostaglandin F-2 alpha and an intravaginal progesterone insert promotes follicular maturity in advance of gonadotropin-releasing hormone among postpartum beef cows
Bonacker et al., 2020
Treatments promoting follicular maturity prior to 7-d CO-Synch + CIDR were evaluated.
PGF2α and CIDR for 7 days increased follicle size and serum estradiol at GnRH.
CL status at final PGF2α and estrous response prior to FTAI tended to be improved
Effect of progesterone supplementation in a resynchronization protocol on follicular dynamics and pregnancy success
Epperson et al., 2020
The incorporation of a CIDR in a resynchronization protocol was not necessary to achieve adequate pregnancy rates.
Inclusion of a CIDR in a resynchronization protocol benefited heifers.
Early pregnancy detection on day 28 using a chute-side blood pregnancy test was found to be as reliable as ultrasonography.
Sensor technology to support herd health monitoring: Using rumination duration and activity measures as unspecific variables for the early detection of dairy cows with health deviations
Gusterer et al., 2020
Differences in activity and rumination data recorded by a accelerometer were observed between healthy and diseased cows.
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Rumination times per day were shorter starting 5 days before clinical diagnosis in diseased cows compared with healthy cows.
’High active’ time started to be shorter 3 days before the clinical diagnosis in diseased cows.
Times cows spent ’inactive’ were significantly longer 3 days before the clinical diagnosis.
Lying time started to be longer 1 day before the clinical diagnosis of disorders in diseased cows
Differences in sperm functionality and intracellular metabolites in Norwegian Red bulls of contrasting fertility
Narud et al., 2020
Bulls of contrasting NR56 differed in sperm quality parameters and metabolome.
Metabolite analyses was performed on viable frozen-thawed sperm cells.
A model including DFI, aspartic acid, Fe and Zn explained variation in bulls’ NR56.
Antibacterial defense in bull and boar semen: A putative link to the microbiome and reproductive strategy?
Schulze et al., 2020
Sixty bull ejaculates were analyzed for bacterial killing activity and lysozyme.
Four-fifths of the samples had no ejaculate-associated defense against E. coli.
Lysozyme concentration in seminal plasma correlated with age of bull.
Lysozyme concentration in seminal plasma correlated with bull sperm quality.
Reproductive strategies & microbiome explain BKA differences between bull & boar ejaculate.
Comparison of behavioral patterns of dairy cows with natural estrus and induced ovulation detected by an ear-tag based accelerometer
Schweinzer et al., 2020
- Used an ear-tag based 3D-accelerometer system (SMARTBOW, Smartbow GmbH, Weibern, Austria) to generate data of behavioral patterns, i.e., rumination and activity.
- Part 1: behavioral patterns during the peri-estrus period were compared between cows with physiological estrus and cows subjected to an Ovsynch protocol.
▪ On the day before estrus and on the day of estrus/AI, cows with natural estrus showed a clear drop in rumination and inactivity and an increase in high activity, based on an algorithm of the accelerometer system, whereas, cows in the Ovsynch protocol showed only minor changes in behavioral patterns. - Part 2: analyzed behavioral patterns between synchronized cows that became pregnant after AI and synchronized cows that remained open.
▪ No differences were detected between these two Ovsynch groups before AI. - In this study we found no evidence that behavioral patterns can be used to improve conception rates within an Ovsynch protocol
Reproductive performance following a modified Presynch-Ovsynch, Double-Ovsynch, or conventional reproductive management program in Korean dairy herds
Kim et al., 2020
Modified Presynch-Ovsynch involved the administration of additional GnRH before Ovsynch.
Presynch-G-Ovsynch and Double-Ovsynch improved reproductive performance.
Presynch-G-Ovsynch yielded similar reproductive outcomes to Double-Ovsynch.
There were no marked differences in ovarian structure or progesterone concentration
Optimization of a 5-day fixed-time embryo transfer (FTET) protocol in heifers I. Manipulation of circulating progesterone through reutilization of intravaginal progesterone devices during FTET
Sala et al., 2020
Efficiency of recipient utilization is increased for FTET compared to ET after estrus.
The CIDR P4 device can be reutilized up to 4 times but with progressively lower P4.
Heifers with reutilized CIDRs had larger preovulatory follicles but similar fertility.
Reutilizing CIDRs is not detrimental to recipient utilization or reproductive efficiency
When reused for FTET, there were no differences (P > 0.05) in utilization rate, P/ET, or P/treated between 1st, 2nd, 3rd or 4th use CIDRs
Field trial on the post-insemination intrauterine treatment of dairy cows with mild endometritis with cephapirin
Schlegl et al., 2020
Post-AI intrauterine treatment with cephapirin in endometritic cows was studied.
Cephapirin treatment did not improve reproductive performance.
Season and a history of clinical endometritis decreased the pregnancy risk.
Uterine pathogenic bacteria were rarely detected in cows with clinical endometritis.
Post-AI intrauterine cephapirin treatment must be regarded as questionable.
Intraovarian influence of bovine corpus luteum on oocyte morphometry and developmental competence, embryo production and cryotolerance
Argudo et al., 2020
The influence of the bovine CL on oocyte morphometric and functional characteristics and embryo development was assessed.
Oocytes from CL ovaries were larger, with thinner zona pellucida, and shown lower activity of G6PDH than ovaries lacking a CL
Corpus luteum did not influence nuclear maturation rate, oocyte diameter and zona pelucida thickness after maturation.
Presence of a CL was associated with a greater cleavage rate and yielded more total embryos and blastocysts.
Embryo cryotolerance was unaffected by the presence of a CL.
Corpus luteum influenced oocyte developmental competence and embryo development presumably through intraovarian interactions
Treatment with an elevated dose of the GnRH analogue dephereline in the early luteal phase improves pregnancy rates in repeat-breeder dairy cows
Lopez-Gatius and Garcia-Ispierto, 2020
- Treatment given either as a single or 2.5 dose increased the probability of an additional corpus luteum (more corpora lutea than embryos) in pregnant cows.
- A dephereline dose 2.5 times higher than normal led to improved pregnancy rates, thus overcoming the impacts of repeat-breeder syndrome.
- Importantly, both the single and 2.5 dephereline doses increased the chances of pregnant cows having an additional corpus luteum, likely favoring embryo survival.
-Dephereline may overcome the effects of repeat-breeder syndrome.
Performance and optimization of an ear tag automated activity monitor for estrus prediction in dairy heifers
Macmillan et al., 2020
- The sensitivity was 91.0%, with a false positive and false negative rate of 8.0%, and the positive predictive value to detect true estrus events was 83.5%.
- Pregnancy per AI to first AI was 67.6% and 97.9% of heifers become pregnant after four inseminations.
- The average (range) interval of onset of high activity, peak activity and end of high activity to OV was 28 h (16-46 h), 22 h (10-40 h) and 16 h (0-36 h), respectively.
- For conventional semen, each hour increase in interval from activity onset or peak activity to AI reduced the predicted probability of pregnancy by 3.8 and 4.2%, respectively
Pregnancy rate to first AI was 66% and 98% were pregnant after 4 inseminations
Pregnancy risk was not associated with estrus strength or duration
For conventional semen, breeding soon after estrus alert increased pregnancy risk
Metabolic markers for purulent vaginal discharge and subclinical endometritis in dairy cows
Pascottini et al., 2020
Cows diagnosed with PVD or SCE at 35 d postpartum have greater Hp concentrations than healthy cows.
NEFA, BHB, IGF-1 and cholesterol differed in cows that were later diagnosed with SCE.
Variations in the energy metabolism and inflammatory profile precede distinct manifestations of reproductive tract disease
Before diagnosis, PVD or SCE had more indication of postpartum systemic inflammation (high Hp and low albumin) than healthy cows, and markers of energy status were more compromised in SCE than in PVD or healthy cows.
- This supports the hypothesis that SCE is associated with maladaptation to postpartum metabolic demands and with metabolic inflammation
Efficacy of ovulation synchronization with timed artificial insemination in treatment of follicular cysts in dairy cows
Abdalla et al., 2020
In follicular cyst, weekly GnRH until detection of a CL before Ovsynch improved P/AI.
New CIDR and G-New CIDR tended to improve the P/AI in cows with follicular cysts.
Reused CIDR inserts on days 0–7 of the Ovsynch did not improve the P/AI.
P4 concentrations up to 7 days post-insertion of new and reused-CIDR were similar
Effect of a puberty induction protocol based on injectable long acting progesterone on pregnancy success of beef heifers serviced by TAI
De Lima et al., 2020
A long-lasting source of P4 stimulates uterine and follicular development of prepubertal beef heifers.
An induction protocol based only on injectable hormones hastens puberty in beef heifers.
This induction protocol increased fertility of beef heifers submitted to timed-AI.
The protocol is a practical way to induce puberty in beef heifers
Sire contribution to pregnancy loss in different periods of embryonic and fetal development of beef cows
Franco et al., 2020
Considerable variance in pregnancy rate and pregnancy loss exists among bulls selected for artificial insemination that cannot be explained by variation in visual semen analysis.
Sire phenotype in regard to pregnancy loss differed depending on the interval of embryonic and fetal development.
Making sire fertility decision solely based on a single pregnancy check can be an inaccurate assessment.
The development of markers that can identify sires of high or low pregnancy loss would be very beneficial to improve sire fertility evaluation and increase beef and dairy reproductive efficiency
Individual sires had different phenotypes in regard to pregnancy loss during different developmental periods, indicating the importance of evaluating multiple milestones of embryonic development when classifying sire fertility
Prostaglandin F-2 alpha influences pre-ovulatory follicle characteristics and pregnancy per AI in anovular dairy cows
Lopes et al., 2020
Treatment of anovular cows with a second dose of 25 mg of prostaglandin F2α increased pregnancy per AI in normothermic cows.
Treatment with prostaglandin F2α had minor impacts on LH pulsatility, but increased the size and estradiol content in the pre-ovulatory follicle.
Prostaglandin has a role in fertility of anovular cows that is unrelated to its luteolytic effect
Supplementation of rangeland primiparous Bos indicus x Bos taurus beef heifers during lactation. 2. Effects upon the reproductive development of bull calf progeny
Callaghan et al., 2020
Protein supplementation of grazing primiparous beef heifers during lactation improves milk production and liveweight gain.
Lactational protein supplementation increases weaning weight of bull progeny, calfhood IGF-I and leptin concentrations.
Enhanced calfhood nutrition increases carcass muscling to 22 mo of age which can improve the sale value of breeding bulls
In summary, improving the plane of nutrition supplied to Bos indicus x Bos taurus bulls between parturition and weaning via moderate supplementation of grazing dams reduces age at sexual maturity with consequent economic advantages to the producer.
Supplementation of rangeland primiparous Bos indicus x Bos taurus beef heifers during lactation. 1. Effects on dam milk production and liveweight, bull calf growth, live carcass characteristics and metabolic hormone concentrations
Callaghan et al., 2020
Protein supplementation of grazing primiparous beef heifers during lactation improves milk production and liveweight gain.
Lactational protein supplementation increases weaning weight of bull progeny, calfhood IGF-I and leptin concentrations.
Enhanced calfhood nutrition increases carcass muscling to 22 mo of age which can improve the sale value of breeding bulls.
Applied use of interferon-tau stimulated genes expression in polymorphonuclear cells to detect pregnancy compared to other early predictors in beef cattle
de Melo et al., 2020
- Commercial ELISA assays for determination of PAG provide a highly accurate method for pregnancy detection when used in milk and blood at 28–30 days after AI
- Both ISG expression and PAG concentrations were greater (P < 0.05) in pregnant females than in non-pregnant and females
- Neither ISG expression nor PAG concentrations were able to predict pregnancy losses after 30 days of pregnancy.
- ISG15 expression was greater (P < 0.05) in heifers than in cows, but this difference was not found in OAS1 expression.
Testicular hyperthermia reduces testosterone concentrations and alters gene expression in testes of Nelore bulls
Rizzoto et al., 2020
Scrotums of Nelore (Bos indicus) bulls were insulated from 0 (Control) to 48 h.
After 48 h, testes were ∼3 °C warmer, with 90% less testosterone.
mRNA abundance of STAR and BCL2 decreased, whereas GPX1 and HSP70 increased.
Apotosis prevented by increased HSP70, but promoted by lower BCL2
Relationships between early postpartum nutritional and metabolic profiles and subsequent reproductive performance of lactating dairy cows
Macmillan et al., 2020
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The metabolic and nutritional profile in early postpartum was assessed in relation to fertility in dairy cows .
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Pregnancy failure to first AI was associated to high serum concentrations of AST, NEFA and haptoglobin.
Pregnancy success to first AI was associated to high serum concentrations of Mg and cholesterol.
Cows that lost their pregnancy after first AI had greater serum concentrations of haptoglobin than cows maintaining pregnancy.
Pregnancy outcome by 150 DIM was negatively associated to serum concentrations of haptoglobin
The relationships among sire’s predicted transmitting ability for daughter pregnancy rate and cow conception rate and daughter’s reproductive performance in Canadian Holstein cows
Gobikrushanth et al., 2020
- Daughter Pregnancy Rate is defined as the percentage of nonpregnant cows that become pregnant during each 21-day period. A DPR of ‘1’ implies that daughters from this bull are 1% more likely to become pregnant during that oestrus cycle than a bull with an evaluation of zero
- Sire’s PTA for DPR was strongly and positively associated with sire’s PTA for cow conception rate (CCR)
- Sire’s PTA for DPR was significantly associated with PR150 (P = 0.03).
- Sire’s PTA for CCR was not associated with P/AI or PR150.
- Neither sire’s PTA for DPR nor CCR were associated with PL.
The proportion of tyrosine phosphorylated spermatozoa in cryopreserved semen is negatively related to crossbred bull fertility
Vignesh et al., 2020
Global tyrosine phosphorylation status was assessed in cryopreserved spermatozoa from bulls with varying field fertility.
The proportion of tyrosine phosphorylated spermatozoa was significantly high in below-average fertile bulls.
Tyrosine phosphorylation at acrosome and post-acrosomal area was negatively related to bull fertility.
The proportion of live tyrosine-phosphorylated spermatozoa in cryopreserved semen was negatively related to bull fertility
Field trial on the post-insemination intrauterine treatment of dairy cows with mild endometritis with cephapirin
Schlegl et al., 2020
- Cephapirin treatment 6 h after AI in cows with mild endometritis did not increase the proportion of pregnant cows after the AI directly preceding the enrolment (P=0.49).
- A significant difference between the percentage of pregnant cows between groups was not identified.
- No differences in mean enrolment to conception interval and calving-conception interval between groups was identified
- Staphylococcus (25/127, 19.7%), Bacillus (16/127, 12.6%) the most common isolates on culture
- Cephapirin treatment in cows with mild CE at AI did not significantly increase the proportion of pregnant cows compared with the untreated CON group
Post-AI intrauterine cephapirin treatment must be regarded as questionable
Effect of two postpartum intramuscular treatments with beta-carotene (Carofertin (R)) on the blood concentration of beta-carotene and on the reproductive performance parameters of dairy cows
Hye et al., 2020
Administration of β-carotene increased blood β-carotene concentrations in dairy cows.
Two postpartum administrations of beta-carotene did not improve fertility in dairy cows.
No effect on luteal size.
No effect on blood progesterone levels.
Results should be interpreted as herd specific.
Evaluation of an investigative model in dairy herds with high calf perinatal mortality rates in Switzerland
Mock et al., 2020 (Mee author)
See attached photo
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The perinatal mortality (PM) rate in this study was 10% at the farm-level, and at the cow-level, 11.5%. These values, from high-risk farms, were approximately five-times higher than the contemporary national bovine PM rate (2.3%) in Switzerland.
The majority of calves died intrapartum. The most commonly diagnosed initiating/ultimate cause of death (UCOD) was infection of which Coxiella burnetii was the most frequently detected pathogen, by antigen.
The investigative model and research methods used in this study have external validity, which can be replicated and re-evaluated, respectively, in future studies on PM internationally
Administration of nerve growth factor-beta to heifers with a pre-ovulatory follicle enhanced luteal formation and function and promoted LH release
Stewart et al., 2020
Nerve growth factor-beta (NGF) increased pre-ovulatory follicle size.
NGF increased LH release and expression of LH receptors in luteal tissue.
NGF increased luteal mRNA abundance of steroidogenic enzyme STAR.
NGF increased small luteal cell number and serum progesterone concentrations.
Administration of NGF improved CL function in heifers potentially as a result of increased LH release.
Plasma estradiol-17 beta, cortisol, and insulin concentrations and serum biochemical parameters surrounding puberty in Japanese Black beef bulls with normal and abnormal semen
Weerakoon et al., 2020
Greater serum aspartate aminotransferase and magnesium and plasma cortisol concentrations were observed in pubertal Japanese Black beef bulls with abnormal fresh semen.
Lower plasma estradiol-17β and insulin concentrations were found in the pubertal beef bulls with low fertility in post-thaw semen.
Increased serum creatinine concentrations from the pre-puberty to puberty might be associated with sperm morphological defects
- Fresh semen abnormality in pubertal beef bulls might be associated with increased circulating aspartate aminotransferase, magnesium and cortisol.
- Low-fertility post-thaw semen could have been involved with the lower peripheral estradiol and insulin levels in beef bulls.
A new paradigm regarding testicular thermoregulation in ruminants?
Rizzoto and Kastelic, 2020
- Increased testicular temperature reduces percentages of morphologically normal and motile sperm and fertility.
- Specific sperm defects appear at consistent intervals after testicular hyperthermia, with degree and duration of changes related to intensity and duration of the thermal insult.
- There is a long-standing paradigm that:
▪ 1) testes operate near hypoxia;
▪ 2) blood flow to the testes does not increase in response to increased testicular temperature; and
▪ 3) an ensuing hypoxia is the underlying cause of heat-induced changes in sperm morphology and function. - There are very limited experimental data to support this paradigm, but we have data that refute it.
- Increased testicular temperature had deleterious effects on sperm motility and morphology; however, hyperoxia did not prevent these changes nor did hypoxia replicate them.
- As testicular temperature increased, testicular metabolic rate nearly doubled, but increased blood flow and O2 extraction prevented testicular hypoxia and anaerobic metabolism.
Relationship between body conditions and environmental contaminants in bovine ovarian cells
Sirotkin et al., 2020
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Body condition/metabolic state and pollutants affect bovine ovarian cell proliferation, apoptosis and hormones release.
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The response of ovarian cells to environmental contaminants can be defined by cow body condition/metabolic state
Angus sire field fertility and in vitro sperm characteristics following use of different sperm insemination doses in Brazilian beef cattle
Zoca et al., 2020
- Pregnancy per TAI (P/TAI) did not differ between sperm doses (43.8, 45.3, 43.8 and 47.1% for 10, 20, 20 or 40 x 10(6) sperm respectively; P = 031) nor was there an interaction between bull and dose (P = 0.53)
- Although fertility differences between bulls were detected, neither sperm per dose nor post-thaw in vitro sperm analyses (CASA and FC) were able to explain the observed differences in field fertility between bulls, further illustrating the difficulties in predicting bull fertility
The objective was to determine if bull fertility varied by sperm dose inseminated.
Treatments were 10, 20 and 40 × 106 sperm per dose.
Pregnancy per timed AI did not differ between sperm doses.
Pregnancy per timed AI was different between bulls.
Metabolic biomarkers, body condition, uterine inflammation and response to superovulation in lactating Holstein cows
Kasimanickam et al., 2020
Mean number of total ova and embryos was significantly higher for cows with no subclinical endometritis.
Mean number of total ova and embryos was significantly lower for cows with BCS 2.00 to <2.50 and with BCS 4.00 to 5.00.
Circulating adiponectin, leptin, insulin, IGF1 and TNFα were greater in cows with moderate to good body condition.
Circulating adiponectin, leptin, IGF1 and insulin concentrations were greater in cows with no subclinical endometritis.
Circulating TNFα and IL1β and IL6 concentrations were greater in cows with subclinical endometritis.
Quadratic associations was observed between metabolic biomarkers, body condition, uterine PMN and superovulatory response.
Presynchronization with prostaglandin F-2 alpha and prolonged exposure to exogenous progesterone impacts estrus expression and fertility in beef heifers
Oosthuizen et al., 2020
Delaying TAI to 72 h increased the percentage of heifers exhibiting estrus after presynchronization with prostaglandin F2α.
Delaying TAI to 72 h in heifers presynchronized with prostaglandin F2α resulted in a tendency for an increase in PR/AI.
Presynchronization with prostaglandin F2α and a CIDR insert resulted in an increase in PR/AI when TAI was performed at 54 h
Early resynchronization of non-pregnant beef cows based in corpus luteum blood flow evaluation 21 days after Timed-Al
Palhao et al., 2020
Resynchronization protocol starting with 1 mg of estradiol benzoate and progesterone device at 13 d after TAI in beef cows.
Beginning at D13 after TAI, this hormone protocol did not interfere with pregnancy recognition and pregnancy rates.
This early resynchronization allowed re-insemination at D23 and cumulative conception rate of the 70.5
Influence of Sexcel (TM) (gender ablation technology) gender-ablated semen in fixed-time artificial insemination of beef cows and heifers
Perry et al., 2020
Conventional semen had greater conception rates compared to gender-ablated semen.
Estrus increased conception rates with both gender-ablated and conventional semen.
Gender-ablated semen conception rates only tended to be decreased among animals in estrus.
Conventional semen had greater conception rates when animals did not exhibit estrus.
Presynchronization with CIDR, with or without GnRH, prior to CO-Synch in beef heifers
Ratzburg et al., 2020
Angus-cross beef heifers synchronized with CIDR–CO–Synch versus CIDR-GnRH–CO–Synch protocols.
Greater number of heifers with corpus luteum at PGF2α in CIDR-GnRH–CO–Synch group.
Average size of the largest ovarian follicle at the time of AI was greater for heifers in CIDR-GnRH–CO–Synch.
AI pregnancy did not differ between CIDR–CO–Synch and CIDR-GnRH–CO–Synch groups.
Research and development of a silicone letrozole-releasing device to control reproduction in cattle
Zwiefelhofer et al., 2020
A silicone intravaginal device was developed for the delivery of letrozole, both in vitro and in vivo
By increasing the surface area of a silicone intravaginal letrozole releasing device (LRD), plasma letrozole increased
Plasma estradiol concentrations were suppressed in heifers given a large surface area LRD containing 15% letrozole
The mean diameter of the dominant follicle was the largest in heifers given a large surface area LRD containing 15% letrozol
Relationships between size, steroidogenesis and miRNA expression of the bovine corpus luteum
Donadeu et al., 2020
Transcript levels of miRNAs, STAR and CYP11A1 do not depend on luteal weight/volume.
Plasma progesterone levels correlate with luteal weight, not with STAR, CYP11A1 or miRNAs.
Luteal CYP11A1 and STAR levels are consistently correlated with miR-182 and with each other
Cyclicity, estrus expression and pregnancy rates in beef heifers with different reproductive tract scores following progesterone supplementation
Kasimanickam et al., 2020
Progesterone (P) advanced cyclicity in beef heifers with reproductive tract score (RTS) 2 to 4.
CO-Synch + P improved estrus expression in heifers with RTS 4 and 5, but not for 2 and 3 compared with CO-Synch alone.
CO-Synch + P protocol improved pregnancies in heifers with RTS 3, 4 and 5, but not for 1 compared with CO-Synch alone
Progesterone-based timed AI protocols for Bos indicus cattle II: Reproductive outcomes of either EB or GnRH-type protocol, using or not GnRH at AI
Madureira et al., 2020
Ovarian dynamics and fertility of EB and GnRH-types of synchronization protocol were studied in Bos indicus.
Each protocol caused different follicle and corpus luteum patterns, but both had similar pregnancy per AI.
Administration of GnRH at AI increased the fertility of cows that did not express estrus.
- In heifers, there was no interaction of GnRH at AI with estrus, however
- Cows that did not display estrus had greater P/AI if they received GnRH at AI (GnRH = 59.1 [91/154] vs. No GnRH = 48.2% [78/162]).
- Treatment with GnRH at time of AI increased fertility in some instances in Bos indicus cows but not in heifers.
Progesterone-based timed AI protocols for Bos indicus cattle I: Evaluation of ovarian function
Madureira et al., 2020
Follicle and corpus luteum development, and circulating progesterone were studied during distinct synchronization protocols.
The EB and GnRH-type protocols induced emergence of a follicle wave by different mechanisms.
Protocols tested during this study caused high ovulation rate at the end and are promising for fertility outcomes.
- 3 protocols: 5d P4, at CIDR removal estradiol, cloprostenol and eCG, as before but a 9d CIDR, 7d CIDR with GnRH
- GnRH and EB protocols had follicle dynamics synchronized by distinct mechanisms that produced differences in CL number and P4 at the time of PGF treatment but similar final ovulation.
Composition and diversity of the preputial microbiota in healthy bulls
Wickeare et al., 2020
Bacteria belonging to Firmicutes, Fusobacteria, Bacteroidetes, Proteobacteria, and Actinobacteria were identified.
The bull penile microbiome includes members of genera that are common in soil, cow vagina, respiratory tract, and feces.
Bulls within this dataset can be split in to high diversity and low diversity categories
The baseline preputial microbial
community in healthy bulls is described in the current study.
Lipidomic profiling of dairy cattle oocytes by high performance liquid chromatography-high resolution tandem mass spectrometry for developmental competence markers
Chen et al., 2020
Lipidomic profiling with HPLC/MS was used to identify degenerating bovine oocytes.
TAG, FFA, and CL involved in energy metabolism disorder in degenerating oocytes.
Degenerating oocytes showed 1.8-fold higher TAG and 53.5% lesser CL than normal.
TAG composition and FFA profile were associated with oocyte degeneration.
Phospholipids were linked to declined enzymatic function in oocyte development.
Increase of triacylglycerols together with the decrease of certain phospholipid species could be potential markers of oocyte developmental competence.
Intravenous infusion of kisspeptin increased serum luteinizing hormone acutely and decreased serum follicle stimulating hormone chronically in prepubertal bull calves
Northup et al., 2020
Kisspeptin (KP) is a hypothalamic neuropeptide that stimulates the secretion of gonadotropin releasing hormone
IV infusions of kisspeptin in prepubertal bull calves, measurement of LH and FSH.
Acute infusion of KP increased LH concentrations
Chronic infusion of KP decreased FSH concentrations.
Despite the potential suppression of the hypothalamic-pituitary-gonadal axis with chronic infusion of KP, there are likely applications of KP, KP analogs, or KP receptor agonists to hasten the onset of puberty in livestock
