Cows in Calf
Vet Webinar
7.30 PM - 9.00 PM
Speakers:
- Dr. Federico Randi - DVM & PHD. International Technical Manager, Ruminant Corporate Marketing, CEVA Santé Animale
- Dr. Lauren Popiolek - DVM, BSA. Interchem's Veterinary Technical Advisor
- Craig Fairbairn BVSC - Interchem's Veterinary Advisor
- Preparation for the breeding season and managing the problem cow
- Sexed semen tips and review of trial work
- FTAI protocols review
- How to easily integrate FTAI into your practice
Farmer webinar
- Dr. Federico Randi - DVM & PHD. International Technical Manager, Ruminant Corporate Marketing, CEVA Santé Animale
- Dr. Lauren Popiolek - Interchem's Veterinary Technical Advisor
- Niall Duffy - Dovea Genetics Dairy Programme Manager
- John Lynch - Dovea Genetics Beef Programme Manager
- How to optimise fertility with sexed semen
- Teagasc Trial work on sexed semen
- How to manage problem cows in the herd
- Synchronisation
- Sire selection
- ICBF EBI march update
- Dairy beef sires
RainBĂł Roller tail paint
Oligovet Ruminant Bolus Range Brochure
Cattle Gestation Calculator
Ask your vet for the highest-dose progesterone device on the Irish market that has been trialled by Teagasc to achieve optimal fertility results.
- Optimal follicular development and oocyte quality8,9
- Improved embryo quality and survival8,9,11
No. 1 Plan your mating start date
- Calving should coincide with spring pasture turnout to maximise grass-based nutrition and optimise profitability (see graph).Â
- The 6-week calving rate is currently at 65% and the aim is for 90%. This shortfall causes a loss of €206/cow1 and has a major impact on carbon emissions.Â
- 15 April M.S.D. will result in calving starting from 12 January 2025.Â
- Impact of 1% difference in 6-week calving rate costs €8.22/cow.2Â
- Speak to your vet and AI technician and ask how synchronisation can achieve 100% submission on the M.S.D.Â
- A key benefit of synchronisation is advancing the mating start date. In a compact breeding system, this enables up to an additional 3 weeks in the breeding season for repeat service. Synchronisation is a critical tool in a targeted breeding programme to optimise a 12-week breeding season.
Harnessing grazing systems to be more profitable
No. 2 Pre-breeding checklist
- Heat detection prior to M.S.D. will identify any noncycling heifers and cows and leave time for vets to intervene and make recommendations.
- RainBĂł Roller tail paint is a convenient and economical oestrus detection aid available for farmers to effectively identify cycling heifers and cows.
- Body condition scoring is also important.Any cows with BCS ≤2.5 can start once daily milking and supplemental nutrition programmes to aid in condition gain that is necessary to optimise their fertility.
- Glycoline dietary complementary feed for dairy cows, ewes and goats contains a synergistic mix of glucose precursors including monopropylene glycol, sorbitol, glycerol, and propionate. Glucose is necessary for follicular recruitment and growth as well as quick uterus involution.
- Metricheck evaluationto identify any cases of endometritis enables time for treatments prior to M.S.D.
- 10-20% of cows will have subclinical or clinical metritis, resulting in reduced reproductive performance.
- Failure to detect metritis can lead to reduced submission rates, reduced 6-week in-calf rates, and reduced days in milk.
- If a corpus luteum is present and prostaglandin treatment is elected for management of chronic metritis, natural prostaglandin (dinoprost) has a superior uterotonic effect when compared to d-cloprostenol, a synthetic prostaglandin.4
Metricheck evaluation scoring5
No. 3 Why use synchronisation?
- Reduce labour - No labour-intensive heat detection, a single AI technician visit, and handle animals in groups with straightforward protocols.Â
- Eliminates heat detection - Avoid the costs of missed heat detections. Over half of cows will come into heat from 9 pm-7 am and nearly half display signs of heat for ≤ 8 hr, making visual observation problematic.Â
- Achieve 100% submission rates on the mating start date by inducing a timed ovulation to facilitate a seasonal calving pattern.Â
- Treat noncycling cows with synchronisation to shorten the calving interval.Â
- Enhance profitability - In the seasonal calving system, FTAI synchronisation with PRID E has proven to have a profit advantage over AI on heat detection. The greatest profit advantage can be achieved when synchronisation is used with sex-sorted semen in heifers and cows at an average €41.52/cow advantage.6
Farmers can earn more money when they use synchronisation!
Profit advantage of synchronisation with conventional semen (CONV) and sexed semen (Sexed) in heifers and both heifers and lactating cows over conventional semen AI to observed heat.6
No. 4 Synchronisation with sexed semen
Sexed semen has reduced relative pregnancy rates compared to conventional semen. It is important to mitigate risk factors associated with sexed semen use to achieve strong fertility results and profitability.Â
Here are four key advantages to using FTAI with sexed semen to optimise fertility:Â
1. Time AI to correspond with ovulation and manage narrower window of sperm viability (Fig. 1)Â
- Sexed semen goes through a sorting process that damages the sperm. It is a more fragile product that does not survive as long in the female reproductive tract (12-16 hours vs. >24 hr conventional semen).7Â
- Reduced sexed semen sperm viability creates a narrow fertility window around ovulation, and timing of insemination is more crucial.Â
- The recommendation for sexed semen is to service 14-20 hr after the onset of oestrus.7Â
- Synchronisation allows the timing of ovulation to be controlled by the protocol. Service can be scheduled to coordinate narrow sperm viability with ovulation to optimise fertility.
- FTAI advances submission of heifers and cows to the mating start date, facilitating a compact fertility season.Â
- Even if reduced conception rates occur with sexed semen, dams still have the full breeding season to achieve a pregnancy without negative effects on the calving pattern.Â
- Replacement heifers calve early in the season to enable maximum time for growth and development prior to first service.
- Sexed semen should be used on selected heifers and elite cows to optimise calf crop and profit.Â
- Synchronisation will ensure the AI technician can service the intended dam and she is not missed due to the tight window for AI after observed heat. (Fig. 2)
- Synchronisation and sexed semen are complementary technologies that can be implemented to further enhance profits.Â
- Irish research has confirmed synchronisation using the highest-progesterone device with sexed semen is a profitable endeavour for most farmers. (Fig. 3)
- Synchronisation with sexed semen used on heifers and cows averages €41.52 profit advantage per cow per year over AI on observed heat.
Fig. 1: Timing of AI with conventional and sexed semen (Stephen Butler, Teagasc)
Fig. 2:Â Example of 5 heifers with different times of first observed heat. Â Even with AI technician visiting at 7 am and 3 pm, one heifer is still not within the suitable window for sexed semen.7
Fig. 3:Â Example of 5 heifers with different times of first observed heat. Â Even with AI technician visiting at 7 am and 3 pm, one heifer is still not within the suitable window for sexed semen.7
No. 5 Importance of progesterone
- Controls follicular development – progesterone impacts age and health of ovulated oocyte (“egg”)
- Key role in maintenance of pregnancy
- Achieving ideal ovulatory oocyte (“egg”) size and age is an important factor influencing the success of a fertility program. It is, therefore, essential to provide high progesterone during the luteal phase to optimise results.8,9
- Maximal conception rates occur when ovulatory follicles develop under circulating progesterone > 2 ng/mL.10
- Progesterone levels are also positively correlated with embryonic survival. 20-50% of pregnancy loss occurs during Day 1-7 and is influenced by oocyte quality and progesterone levels before AI.11
The predicted probability of pregnancy 39 days post artificial insemination based on circulating concentrations of progesterone (P4) at time of final prostaglandin F2a (PGF) of Ovsynch in lactating dairy cows.9
Ask your vet for the highest-dose progesterone device on the Irish market that has been trialled by Teagasc to achieve optimal fertility results.
- Optimal follicular development and oocyte quality8,9
- Improved embryo quality and survival8,9,11
No. 6 Getting cows back in calf at the end of the breeding season
Synchronisation benefits:Â
Overcomes anoestrus (noncycling cows): The use of synchronisation protocols will promote cyclicity in cows that are in postpartum anoestrus.Â
- Optimal body condition score (BCS) and nutrition are crucial to optimising fertility and should be addressed in all fertility plans.Â
- Cows should be a minimum 40 days in milk at the time of AI (30 at the start of the protocol) to allow for physiologic uterine involution.Â
- Always assess for reproductive diseases, such as metritis, and other causes of anoestrus that may require interventions.
Manages persistent follicles or cysts: Teagasc synchronisation protocols featuring GnRH on Day 0 will effectively manage cysts to achieve ovulation (Fig. 1).
Enhances profitability: Synchronisation protocols using the highest-dose progesterone device have been shown to increase profitability on Irish dairy farms compared to AI on observed heat.6
Fig. 1:Â Recommended protocols based on published Teagasc trials using the highest-dose progesterone device.12,13,14
References: 1. Teagasc 2020 - Setting the targets for spring breeding - Teagasc | Agriculture and Food Development Authority. [online] Available at: [Accessed 11 March 2022]. • 2. Teagasc 2014. Why is six week calving rate important to my farm. [online] Available at: [Accessed 11 March 2022]. • 3. O’Donovan M. Harnessing grazing systems to be more profitable. Teagasc, Animal & Grasslands Innovation and Research Centre, Moorepark. https://url6.mailanyone.net/scanner?m=1rhtvY-0001Ri-5c&d=4%7Cmail%2F90%2F1709741400%2F1rhtvY-0001Ri-5c%7Cin6a%7C57e1b682%7C26251357%7C11122387%7C65E896A45CEB6FADFE915B9BBC60D914&o=%2Fphtr%3A%2Fptscnesm5.oetsr%2Fhnesiannrg--zigga-tsyomstsee--bpor-emliro-abeftpsbn%26.%2Frd&s=Di77phqXFM4lLqWwZAqwlBOS4XU; • 4. Mallem Y, Desfontis J-C, Gautier F, Gogny M (2003). Uterokinetic effects of dinoprost and d-cholprostenol in the isolated bovine myometrium. J. vet. Pharmacol. Therap. 26 (Suppl. 1):82-307. • 5. Doyle R, Millar C, Holden S, Butler S. Uterine health in pasture based production system. Irish Dairying- Growing Sustainability. Animal & Grassland Research and Innovation Centre Moorepark. 3 July 2019: 206-207. https://url6.mailanyone.net/scanner?m=1rcSkZ-0008cc-54&d=4%7Cmail%2F90%2F1708445400%2F1rcSkZ-0008cc-54%7Cin6k%7C57e1b682%7C26251357%7C11122387%7C65D4CFB7AAFD3EFC5B4197239326CD87&o=%2Fphtw%3A%2Fwtssew..gactaamiewdi%2F%2Fepiebbe%2Fustnali%2Fioscto920eMor1%2FIkpai9-rr1yDshniri-aeog-.kltbofdp&s=IPbpp9Tc5fHtlcUgU5mRMzyXlnY. • 6. Walsh DP, Fahey AG, Longerhan P, Wallace M. Economics of timed artificial insemination with unsorted or sexed semen in high-producing, pasture-based dairy production system. J Dairy Sci. 2022 Feb;105(4):3192-3208. • 7. Appendix 1: Guidelines for sexed semen usage in dairy herds. 2020. Teagasc Agriculture and Food Development Authority; [accessed 30.1.21]. https://url6.mailanyone.net/scanner?m=1rhtvy-0001Fy-3m&d=4%7Cmail%2F90%2F1709741400%2F1rhtvy-0001Fy-3m%7Cin6f%7C57e1b682%7C26251357%7C11122387%7C65E896BE294FE2DF675B851FBF648DA2&o=%2Fphtw%3A%2Fwtssew..gactaamiewdi%2F%2Fepiebbe%2Fustnali%2Fioscti020eGud2%2Foeli--frnseeSee-Smxd-sn-ngeiUaHi-Dry-earfdp.sd&s=pVUjs2xxlzp0BQhnpt7uO2Yf1-I : • 8. Lonergan P. Influence of progesterone on oocyte quality and embryo development in cows. Theriogenology. 2011 Dec;76(9):1594-601. doi: 10.1016/j.theriogenology.2011.06.012. PMID: 21855985. • 9. Pursley JR, Martins JP. Impact of circulating concentrations of progesterone and antral age of the ovulatory follicle on fertility of high-producing lactating dairy cows. Reprod Fertil Dev. 2012; 24: 267–271. • 10. Denicol AC, Lopes G Jr, Mendonça LG, Rivera FA, Guagnini F, Perez RV, Lima JR, Bruno RG, Santos JE, Chebel RC. Low progesterone concentration during the development of the first follicular wave reduces pregnancy per insemination of lactating dairy cows. J Dairy Sci. 2012 Apr;95(4):1794-806. doi: 10.3168/jds.2011-4650. • 11. Wiltbank MC, Baez GM, Garcia-Guerra A, Toledo MZ, Monteiro PL, Melo LF, Ochoa JC, Santos JE, Sartori R. Pivotal periods for pregnancy loss during the first trimester of gestation in lactating dairy cows. Theriogenology. 2016 Jul 1;86(1):239-53. doi: 10.1016/j.theriogenology.2016.04.037. • 12. Drake E, Holden SA, Aublet V, Doyle RC, Millar C, Moore SG, Maicas C, Randi F, Cromie AR, Lonergan P, Butler ST. Evaluation of delayed timing of artificial insemination with sex-sorted sperm on pregnancy per artificial insemination in seasonal-calving, pasture-based lactating dairy cows. J Dairy Sci. 2020 Dec;103(12):12059-12068. • 13. Randi F, Kelly AK, Parr MH, Diskin MG, Lively F, Lonergan P, Kenny DA. Effect of ovulation synchronization program and season on pregnancy to timed artificial insemination in suckled beef cows. Theriogenology. 2021 Sep 15;172:223-229. • 14. Moore SG, Crowe AD, Randi F, Butler ST. Effect of delayed timing of artificial insemination with sex-sorted semen on pregnancy per artificial insemination in synchronized dairy heifers managed in a seasonal-calving pasture-based system. JDS Commun. 2023 Jul 21;4(5):417-421.
Cows in Calf
Vet Webinar
7.30 PM - 9.00 PM
Speakers:
- Dr. Federico Randi - DVM & PHD. International Technical Manager, Ruminant Corporate Marketing, CEVA Santé Animale
- Dr. Lauren Popiolek - DVM, BSA. Interchem's Veterinary Technical Advisor
- Craig Fairbairn BVSC - Interchem's Veterinary Advisor
- Preparation for the breeding season and managing the problem cow
- Sexed semen tips and review of trial work
- FTAI protocols review
- How to easily integrate FTAI into your practice
Farmer webinar
- Dr. Federico Randi - DVM & PHD. International Technical Manager, Ruminant Corporate Marketing, CEVA Santé Animale
- Dr. Lauren Popiolek - Interchem's Veterinary Technical Advisor
- Niall Duffy - Dovea Genetics Dairy Programme Manager
- John Lynch - Dovea Genetics Beef Programme Manager
- How to optimise fertility with sexed semen
- Teagasc Trial work on sexed semen
- How to manage problem cows in the herd
- Synchronisation
- Sire selection
- ICBF EBI march update
- Dairy beef sires
Ask your vet for the highest-dose progesterone device on the Irish market that has been trialled by Teagasc to achieve optimal fertility results.
- Optimal follicular development and oocyte quality8,9
- Improved embryo quality and survival8,9,11
No. 1 Plan your mating start date
- Calving should coincide with spring pasture turnout to maximise grass-based nutrition and optimise profitability (see graph).Â
- The 6-week calving rate is currently at 65% and the aim is for 90%. This shortfall causes a loss of €206/cow1 and has a major impact on carbon emissions.Â
- 15 April M.S.D. will result in typical calving starting from 24th January 2025, while a M.S.D of 29th April will give a start date of 7th Feb (based on 284 day gestation).
- Impact of 1% difference in 6-week calving rate costs €8.22/cow.2Â
- Speak to your vet and AI technician and ask how synchronisation can achieve 100% submission on the M.S.D.Â
- A key benefit of synchronisation is advancing the mating start date. In a compact breeding system, this enables up to an additional 3 weeks in the breeding season for repeat service. Synchronisation is a critical tool in a targeted breeding programme to optimise a 12-week breeding season.
Harnessing grazing systems to be more profitable
No. 2 Pre-breeding checklist
- Heat detection prior to M.S.D. will identify any noncycling heifers and cows and leave time for vets to intervene and make recommendations.
- RainBĂł Roller tail paint is a convenient and economical oestrus detection aid available for farmers to effectively identify cycling heifers and cows.
- Body condition scoring is also important.Any cows with BCS ≤2.5 can start once daily milking and supplemental nutrition programmes to aid in condition gain that is necessary to optimise their fertility.
- Glycoline dietary complementary feed for dairy cows, ewes and goats contains a synergistic mix of glucose precursors including monopropylene glycol, sorbitol, glycerol, and propionate. Glucose is necessary for follicular recruitment and growth as well as quick uterus involution.
- Metricheck evaluationto identify any cases of endometritis enables time for treatments prior to M.S.D.
- 10-20% of cows will have subclinical or clinical metritis, resulting in reduced reproductive performance.
- Failure to detect metritis can lead to reduced submission rates, reduced 6-week in-calf rates, and reduced days in milk.
- If a corpus luteum is present and prostaglandin treatment is elected for management of chronic metritis, natural prostaglandin (dinoprost) has a superior uterotonic effect when compared to d-cloprostenol, a synthetic prostaglandin.4
Metricheck evaluation scoring5
No. 3 Why use synchronisation?
- Reduce labour - No labour-intensive heat detection, a single AI technician visit, and handle animals in groups with straightforward protocols.Â
- Eliminates heat detection - Avoid the costs of missed heat detections. Over half of cows will come into heat from 9 pm-7 am and nearly half display signs of heat for ≤ 8 hr, making visual observation problematic.Â
- Achieve 100% submission rates on the mating start date by inducing a timed ovulation to facilitate a seasonal calving pattern.Â
- Treat noncycling cows with synchronisation to shorten the calving interval.Â
- Enhance profitability - In the seasonal calving system, FTAI synchronisation with PRID E has proven to have a profit advantage over AI on heat detection. The greatest profit advantage can be achieved when synchronisation is used with sex-sorted semen in heifers and cows at an average €41.52/cow advantage.6
Farmers can earn more money when they use synchronisation!
Profit advantage of synchronisation with conventional semen (CONV) and sexed semen (Sexed) in heifers and both heifers and lactating cows over conventional semen AI to observed heat.6
No. 4 Synchronisation with sexed semen
Sexed semen has reduced relative pregnancy rates compared to conventional semen. It is important to mitigate risk factors associated with sexed semen use to achieve strong fertility results and profitability.Â
Here are four key advantages to using FTAI with sexed semen to optimise fertility:Â
1. Time AI to correspond with ovulation and manage narrower window of sperm viability (Fig. 1)Â
- Sexed semen goes through a sorting process that damages the sperm. It is a more fragile product that does not survive as long in the female reproductive tract (12-16 hours vs. >24 hr conventional semen).7Â
- Reduced sexed semen sperm viability creates a narrow fertility window around ovulation, and timing of insemination is more crucial.Â
- The recommendation for sexed semen is to service 14-20 hr after the onset of oestrus.7Â
- Synchronisation allows the timing of ovulation to be controlled by the protocol. Service can be scheduled to coordinate narrow sperm viability with ovulation to optimise fertility.
- FTAI advances submission of heifers and cows to the mating start date, facilitating a compact fertility season.Â
- Even if reduced conception rates occur with sexed semen, dams still have the full breeding season to achieve a pregnancy without negative effects on the calving pattern.Â
- Replacement heifers calve early in the season to enable maximum time for growth and development prior to first service.
- Sexed semen should be used on selected heifers and elite cows to optimise calf crop and profit.Â
- Synchronisation will ensure the AI technician can service the intended dam and she is not missed due to the tight window for AI after observed heat. (Fig. 2)
- Synchronisation and sexed semen are complementary technologies that can be implemented to further enhance profits.Â
- Irish research has confirmed synchronisation using the highest-progesterone device with sexed semen is a profitable endeavour for most farmers. (Fig. 3)
- Synchronisation with sexed semen used on heifers and cows averages €41.52 profit advantage per cow per year over AI on observed heat.
Fig. 1: Timing of AI with conventional and sexed semen (Stephen Butler, Teagasc)
Fig. 2:Â Example of 5 heifers with different times of first observed heat. Â Even with AI technician visiting at 7 am and 3 pm, one heifer is still not within the suitable window for sexed semen.7
Fig. 3:Â Example of 5 heifers with different times of first observed heat. Â Even with AI technician visiting at 7 am and 3 pm, one heifer is still not within the suitable window for sexed semen.7
No. 5 Importance of progesterone
- Controls follicular development – progesterone impacts age and health of ovulated oocyte (“egg”)
- Key role in maintenance of pregnancy
- Achieving ideal ovulatory oocyte (“egg”) size and age is an important factor influencing the success of a fertility program. It is, therefore, essential to provide high progesterone during the luteal phase to optimise results.8,9
- Maximal conception rates occur when ovulatory follicles develop under circulating progesterone > 2 ng/mL.10
- Progesterone levels are also positively correlated with embryonic survival. 20-50% of pregnancy loss occurs during Day 1-7 and is influenced by oocyte quality and progesterone levels before AI.11
The predicted probability of pregnancy 39 days post artificial insemination based on circulating concentrations of progesterone (P4) at time of final prostaglandin F2a (PGF) of Ovsynch in lactating dairy cows.9
Ask your vet for the highest-dose progesterone device on the Irish market that has been trialled by Teagasc to achieve optimal fertility results.
- Optimal follicular development and oocyte quality8,9
- Improved embryo quality and survival8,9,11
No. 6 Getting cows back in calf at the end of the breeding season
Synchronisation benefits:Â
Overcomes anoestrus (noncycling cows): The use of synchronisation protocols will promote cyclicity in cows that are in postpartum anoestrus.Â
- Optimal body condition score (BCS) and nutrition are crucial to optimising fertility and should be addressed in all fertility plans.Â
- Cows should be a minimum 40 days in milk at the time of AI (30 at the start of the protocol) to allow for physiologic uterine involution.Â
- Always assess for reproductive diseases, such as metritis, and other causes of anoestrus that may require interventions.
Manages persistent follicles or cysts: Teagasc synchronisation protocols featuring GnRH on Day 0 will effectively manage cysts to achieve ovulation (Fig. 1).
Enhances profitability: Synchronisation protocols using the highest-dose progesterone device have been shown to increase profitability on Irish dairy farms compared to AI on observed heat.6
Fig. 1:Â Recommended protocols based on published Teagasc trials using the highest-dose progesterone device.12,13,14
References: 1. Teagasc 2020 - Setting the targets for spring breeding - Teagasc | Agriculture and Food Development Authority. [online] Available at: [Accessed 11 March 2022]. • 2. Teagasc 2014. Why is six week calving rate important to my farm. [online] Available at: [Accessed 11 March 2022]. • 3. O’Donovan M. Harnessing grazing systems to be more profitable. Teagasc, Animal & Grasslands Innovation and Research Centre, Moorepark. https://url6.mailanyone.net/scanner?m=1rhtvY-0001Ri-5c&d=4%7Cmail%2F90%2F1709741400%2F1rhtvY-0001Ri-5c%7Cin6a%7C57e1b682%7C26251357%7C11122387%7C65E896A45CEB6FADFE915B9BBC60D914&o=%2Fphtr%3A%2Fptscnesm5.oetsr%2Fhnesiannrg--zigga-tsyomstsee--bpor-emliro-abeftpsbn%26.%2Frd&s=Di77phqXFM4lLqWwZAqwlBOS4XU; • 4. Mallem Y, Desfontis J-C, Gautier F, Gogny M (2003). Uterokinetic effects of dinoprost and d-cholprostenol in the isolated bovine myometrium. J. vet. Pharmacol. Therap. 26 (Suppl. 1):82-307. • 5. Doyle R, Millar C, Holden S, Butler S. Uterine health in pasture based production system. Irish Dairying- Growing Sustainability. Animal & Grassland Research and Innovation Centre Moorepark. 3 July 2019: 206-207. https://url6.mailanyone.net/scanner?m=1rcSkZ-0008cc-54&d=4%7Cmail%2F90%2F1708445400%2F1rcSkZ-0008cc-54%7Cin6k%7C57e1b682%7C26251357%7C11122387%7C65D4CFB7AAFD3EFC5B4197239326CD87&o=%2Fphtw%3A%2Fwtssew..gactaamiewdi%2F%2Fepiebbe%2Fustnali%2Fioscto920eMor1%2FIkpai9-rr1yDshniri-aeog-.kltbofdp&s=IPbpp9Tc5fHtlcUgU5mRMzyXlnY. • 6. Walsh DP, Fahey AG, Longerhan P, Wallace M. Economics of timed artificial insemination with unsorted or sexed semen in high-producing, pasture-based dairy production system. J Dairy Sci. 2022 Feb;105(4):3192-3208. • 7. Appendix 1: Guidelines for sexed semen usage in dairy herds. 2020. Teagasc Agriculture and Food Development Authority; [accessed 30.1.21]. https://url6.mailanyone.net/scanner?m=1rhtvy-0001Fy-3m&d=4%7Cmail%2F90%2F1709741400%2F1rhtvy-0001Fy-3m%7Cin6f%7C57e1b682%7C26251357%7C11122387%7C65E896BE294FE2DF675B851FBF648DA2&o=%2Fphtw%3A%2Fwtssew..gactaamiewdi%2F%2Fepiebbe%2Fustnali%2Fioscti020eGud2%2Foeli--frnseeSee-Smxd-sn-ngeiUaHi-Dry-earfdp.sd&s=pVUjs2xxlzp0BQhnpt7uO2Yf1-I : • 8. Lonergan P. Influence of progesterone on oocyte quality and embryo development in cows. Theriogenology. 2011 Dec;76(9):1594-601. doi: 10.1016/j.theriogenology.2011.06.012. PMID: 21855985. • 9. Pursley JR, Martins JP. Impact of circulating concentrations of progesterone and antral age of the ovulatory follicle on fertility of high-producing lactating dairy cows. Reprod Fertil Dev. 2012; 24: 267–271. • 10. Denicol AC, Lopes G Jr, Mendonça LG, Rivera FA, Guagnini F, Perez RV, Lima JR, Bruno RG, Santos JE, Chebel RC. Low progesterone concentration during the development of the first follicular wave reduces pregnancy per insemination of lactating dairy cows. J Dairy Sci. 2012 Apr;95(4):1794-806. doi: 10.3168/jds.2011-4650. • 11. Wiltbank MC, Baez GM, Garcia-Guerra A, Toledo MZ, Monteiro PL, Melo LF, Ochoa JC, Santos JE, Sartori R. Pivotal periods for pregnancy loss during the first trimester of gestation in lactating dairy cows. Theriogenology. 2016 Jul 1;86(1):239-53. doi: 10.1016/j.theriogenology.2016.04.037. • 12. Drake E, Holden SA, Aublet V, Doyle RC, Millar C, Moore SG, Maicas C, Randi F, Cromie AR, Lonergan P, Butler ST. Evaluation of delayed timing of artificial insemination with sex-sorted sperm on pregnancy per artificial insemination in seasonal-calving, pasture-based lactating dairy cows. J Dairy Sci. 2020 Dec;103(12):12059-12068. • 13. Randi F, Kelly AK, Parr MH, Diskin MG, Lively F, Lonergan P, Kenny DA. Effect of ovulation synchronization program and season on pregnancy to timed artificial insemination in suckled beef cows. Theriogenology. 2021 Sep 15;172:223-229. • 14. Moore SG, Crowe AD, Randi F, Butler ST. Effect of delayed timing of artificial insemination with sex-sorted semen on pregnancy per artificial insemination in synchronized dairy heifers managed in a seasonal-calving pasture-based system. JDS Commun. 2023 Jul 21;4(5):417-421.