Routine Fertility Visit and Bovine Reproductive Management

Routine fertility visits are essential for proactive dairy farm management, allowing for the establishment of strong relationships with farm clients and a comprehensive understanding of the herd's health. These visits not only facilitate discussions on various herd health issues but also provide veterinary assistance for cases that may not warrant individual farm visits, thereby maximizing the efficiency of veterinary resources.

Reproductive Management
Effective reproductive management encompasses both herd-wide practices and targeted interventions at the individual cow level. It is crucial to assess the wider reproductive goals of the herd, as achieving high fertility rates is key to maintaining productivity in dairy herds. Keeping track of reproductive data helps in making informed decisions and implementing strategies that enhance reproductive success.

Bovine Oestrous Cycle
The bovine oestrous cycle generally lasts between 18 to 24 days, which is critical for understanding breeding timing and interventions. The cycle can be divided into two main phases:

• Luteal Phase: Lasts 14-18 days, during which progesterone predominates due to the presence of a functional corpus luteum, which is essential for maintaining pregnancy.

• Follicular Phase: Lasts 4-6 days, characterized by the predominance of estrogen in the absence of a corpus luteum, leading to the preparatory phase for ovulation, marking the end of this phase.

Follicular Development
Throughout the oestrous cycle, follicular development is crucial, with most adult dairy cows experiencing two follicular waves per cycle. Notably, individual variations can result in one to four waves. This complexity emphasizes that the dominant follicle does not ovulate until there is a significant drop in progesterone levels, thus ensuring effective breeding opportunities.

Hormonal Changes During the Cycle
Understanding the hormonal dynamics during the oestrous cycle is foundational for effective reproductive management:

• Oestrogen: Levels peak shortly before ovulation, which is vital for the triggering of the ovulatory process.

• FSH (Follicle Stimulating Hormone): Secreted by the pituitary gland, initiating the growth and maturation of ovarian follicles.

• LH (Luteinising Hormone): Experiences a peak surge right before ovulation, which is critical for ovulation to occur.

Ultrasound Examination
Ultrasound examination serves as a powerful tool in assessing the reproductive tract of dairy cows. Effective visualizations include:

• Corpus Luteum: Identified by mid-grey echogenicity, a suitable size for palpation or imaging, featuring a central lacuna.

• Follicles: Identified as anechoic, thin-walled structures, which signify healthy ovarian activity when measuring greater than 8mm in diameter, indicating readiness for insemination.

Pregnancy Diagnosis
Pregnancy diagnosis can be conducted via manual palpation or ultrasound. The advantages of using ultrasound include:

• Assessing the viability of the fetus through heartbeat detection and fetal movement, which helps ensure successful pregnancies.

• Informing farmers about any discrepancies between recorded gestation stages and actual assessments, promoting accurate record-keeping.

Routine Checks During Visits
Routine checks during fertility visits are systematic and include:

1. Pregnancy Diagnosis (PD): After mating, distinguishing between:

   • NSB (Not Seen Bullying): Showing that cows were not observed in heat.

   • ONO (Oestrous Not Observed): Indicating heat not detectable.

   • NDO (Non-Detected Oestrous): Identifying non-detected heats.

2. Repeat Breeders: Special attention is given to cows that have been inseminated but are not pregnant despite well-expressed oestrous signs.

3. Post Natal Checks (PNC): These checks are performed within the first three weeks after calving to identify common postpartum issues, such as metritis or retained membranes.

4. Pre-Breeding Checks: Cows are examined before breeding to identify any underlying abnormalities that could affect conception.

Cows for Routine Visits
Cows are grouped for routine visits as follows:

• Early PD: Checked closer to the insemination date.

• Late PD: Evaluated further out from insemination to assess ongoing pregnancies.

• NSB/ONO: Target the cows that have shown no signs of heat.

• Pre-breeding Check: Focus on cows approaching the end of the voluntary waiting period.

• Post Natal: Cows that calved within the last 14 days are prioritized for checks to ensure their health and readiness for future breeding.

Reproductive Disorders Noted in Visits
Several reproductive disorders may be identified during visits, including:

• Pyometra: Presence of pus in the uterus along with a corpus luteum and a closed cervix; often treated successfully with PGF2α in one session.

• Endometritis: An inflammatory condition diagnosed past 21 days post-calving, necessitating grading of discharge from 0-3, with clinical endometritis requiring intrauterine infusion treatment.

• Cystic Ovarian Disease (COD): Differentiates between follicular and luteal cysts based on their wall thickness and ultrasound appearance, with treatment varying based on cyst type; luteal cysts may be treated with PGF2α, while follicular cysts can require diverse management strategies.

Synchronisation Protocols
Common synchronization protocols such as OvSynch and CIDR/PRID Synch are valuable tools; however, it is essential to recognize that OvSynch is typically unsuitable for heifers due to differences in their follicular wave patterns.

Summary
Routine fertility visits play a vital role in the reproductive management of dairy herds, encompassing both treatment and monitoring aspects to ensure herd health. A deep understanding of the oestrous cycle, effective ultrasound examination techniques, and the ability to identify and treat reproductive disorders are essential components for successful dairy farming outcomes, directly impacting productivity