Field Knowledge.
Built for Practitioners.

The problem

Temperature variation above 1.5°C during handling damages the protein responsible for oocyte penetration. The sperm looks normal under microscope — but it can't fertilize.

10 critical steps

• Remove canister from nitrogen tank, work below frost line — max 10 seconds
• Use precooled tweezers, transfer straw to thaw bath in 5 seconds or less
• Thaw at 95°F (35°C) for 45–60 seconds in temperature-controlled bath
• Pull 3 straws at a time — never 10+
• Pre-warm gun to prevent cold shock
• Remove straw, dry with clean towel — do not touch with bare hands
• Load straw in gun, plug end first
• Cut straw at right angle at semen level
• Use within 5 minutes of thawing
• Record: date, cow, bull, technician

Storage rules

• Keep canisters below frost line at all times
• Check nitrogen level weekly, keep above 4 inches (10 cm)
• Store tank raised off ground in dry environment
• Update inventory every time semen enters or exits the tank

Luciano Penteado, owner of Firmasa Tecnologia Para Pecuaria — one of Brazil's leading FTAI specialists — ran a field test on 280 cows. Same semen. Same protocol. Same day. Two groups differing only in straw handling.

The test

• Group A: pulled 10 straws at a time — temperature variation above 1.5°C
• Group B: pulled 3 straws at a time — variation kept below 1.5°C

Result

44% vs 56% conception. 12 percentage points. From one handling step. The sperm looked normal — it would pass a visual assessment — but a specific protein responsible for oocyte penetration was damaged during the temperature drop.

Practical checklist

• Pull straws 3 at a time — never 10+
• Transfer from tank to bath in under 5 seconds
• Thaw at 35–37°C for minimum 30 seconds (45–60 best)
• Use within 5 minutes of thawing
• Check one straw from the batch before committing the rest

📊 Penteado L., Firmasa — 280 cows, InterCorte, Campo Grande MS. Under guidance of Prof. Pietro Sampaio Baruselli, FMVZ-USP.

Equipment

• Thawing bath calibrated to 35–37°C
• Tweezers precooled in nitrogen vapor
• Insemination guns cleaned and warmed
• Thermometer calibrated and working
• Clean dry towels available at station

Storage

• Nitrogen level above 4 inches (10 cm)
• Tank inventory updated and verified
• Canister positions documented
• Tank stored off ground, dry environment

Team

• All technicians briefed on 5-second transfer rule
• Recording sheets ready (date / cow / bull / tech)
• Backup equipment available on-site

Understanding the numbers

• Total motility: percentage of all moving sperm — minimum 50% for approval
• Progressive motility: sperm moving forward in a straight line — minimum 30%
• Concentration: sperm cells per ml — varies by species and dose requirements
• Morphology: percentage of normal-shaped sperm — minimum 70% normal

Borderline results — what to do

• Re-test with a fresh straw from the same batch before rejecting
• Check thawing protocol — temperature errors cause false-low motility
• Compare against the bull's historical baseline if available
• Consider dose adjustment rather than full batch rejection

MAKSA vs CASA correlation

MAKSA correlates with CASA systems at r > 0.90, meaning results are statistically equivalent for field use. Minor differences in absolute values are normal — use consistent methodology for trend tracking.

An internal audit at a large AI center compared conception rates across 3 technicians handling identical semen batches from the same bull on the same day.

The findings

• Technician A: 61% conception rate
• Technician B: 54% conception rate
• Technician C: 43% conception rate

An 18-point gap. Same bull. Same semen. Same day.

Root causes identified

• Differences in straw exposure time during canister retrieval (3 sec vs 11 sec)
• Inconsistent thawing bath temperature maintenance between straws
• Variation in gun pre-warming practice
• Different straw handling — one technician used bare hands

What changed after the audit

• Standardized handling protocol posted at every insemination station
• Pre-season semen quality checks introduced for all technicians
• Conception rate gap narrowed to 4 points within one season

Track conception rates by bull, technician, date, and season. Identify underperformers early and benchmark against your historical baseline.

What the template includes

• Monthly conception rate by bull and technician
• Season-over-season comparison columns
• Automatic average calculation per bull and per technician
• Industry benchmark reference: 50–60% for cattle, 65–75% for sheep
• Notes column for protocol changes and environmental factors

How to use it

• Enter results within 24 hours of each insemination session
• Review weekly with your team — flag any technician below 45%
• Use the season summary tab for annual reporting