11/24/25

Participants in the class are advised to hang up their phones for better focus.
Lizzie will assist with tasks scheduled for the upcoming week as the instructor is unavailable on Mondays.
A transition to discussing dairy cows is indicated, specifically focusing on their life cycle.

The life cycle of a dairy cow will be explored; particularly the relationship between age and milk production.

A scale will be used for the discussion:
- Age (months) on the x-axis.
- Pounds of milk on the y-axis.
This will serve to illustrate the milk production through different stages.

Target Breeding Age: 12 to 14 months.
Variations exist based on breed, with some dairy cows being bred as late as 15 months.
- Most lactations are desired, necessitating early breeding.

Breeding at 12 months: gestation period is approximately $285$ days.
- Equivalent to about 9 months.
By breeding at 12 months, a cow will calve at approximately 21 months.

Milk production after calving begins at zero and typically rises sharply before plateauing.
- Continuous milking can be maintained throughout a cow's life as long as the mammary glands are stimulated.
After calving, cows should usually go through a dry period of 45 to 60 days before being bred again.
- Cows experience estrous cycles every 21 days, but breeding is recommended after the specified dry period to allow proper uterine recovery.
Uterine involution is important - the uterus must return to a pre-pregnant state prior to reinsemination.

Uterine involution enhances fertility rates and extends the likelihood of a successful pregnancy.
The importance of allowing a proper rest period after calving is emphasized by the instructor.

Following first calving at 21 months, there will be an anticipated reduction and stabilization in milk production following subsequent breedings.
- Typical practice involves drying out in the last 60 days of gestation.
- Dry periods help regenerate mammary tissues and assist with producing higher milk yields with each lactation following a rest.
The instructor emphasizes the importance of allowing natural biological rhythms in order to optimize long-term milk production.

Average lifespan of dairy cows in the U.S. is roughly 5 years with around 2.8 lactations.
Causes for earlier culling:
- Mastitis (inflammation of the mammary gland).
- Lameness issues.
Comparative data:
- Countries like the Netherlands have an average of around 8 lactations before culling.

Around 90% of all mastitis cases are subclinical, leading to significant economic loss due to reduced milk quality.
- Estimated financial loss is about $200 per infected cow, considering veterinary therapies and treatment costs.
Somatic Cell Count (SCC) is critical for assessing milk quality, with elevated counts indicating possible mastitis.

Grade 1: Subacute, mild changes.
Grade 2: Visible changes, possibly mild inflammation and temperature increase.
Grade 3: Systemically affected cow showing signs of illness.
Grade 4: Chronic, potentially longstanding issues with multiple quarters affected.

The California Mastitis Test (CMT) assesses milk quality by determining white blood cell presence, indicating mastitis.
Treatment options and protocols for mastitis must consider antibiotic resistance and environmental contamination.
Focus on cow hygiene to mitigate mastitis incidence:
- Pre-dipping prior to milking ensures cleanliness.
- Post-dipping applications after milking to protect from environmental pathogens.

Emphasis on animal welfare is highlighted, especially during outdoor time, adequate space, socialization, and hygiene practices.
Practices such as using brushes and providing cooling systems during hot weather promote health and comfort, leading to increased productivity.

Dairy farming practices exemplify the balance between productivity and animal welfare.
Instructors stress that improvements in dairy cow care can lead to healthier cows, which ultimately results in increased milk production and quality.

Average days to re-breed after calving: 45 to 60 days.
Common mastitis-causing bacteria include:
- Environmental: E. coli, Staphylococcus, Strep species.
- Contagious: Staphylococcus aureus, Strep agalactiae.

Participants encourage maintaining focus on animal well-being and production efficiency.
Open dialogue about cow management practices continues as a means of improving industry standards.