Synchronization protocol compliance

Definition

Synchronization protocol compliance is the share of scheduled protocol steps (hormone injections and the timed insemination) that were actually given on the scheduled day. It measures execution of a timed-AI program, not the biology of the cows.

Timed AI works only if each injection is given on time: the GnRH and prostaglandin (PGF2α) doses are spaced so that a new follicle grows, the corpus luteum regresses and ovulation happens close to the insemination. A missed or late step breaks that sequence, and the cow is inseminated at the wrong time or without ovulating.

Common protocols and step timing

Ovsynch (Pursley et al. 1995), the core of most programs:

Day / time	Step
Day 0	GnRH
Day 7	PGF2α
Day 8 (optional)	Second PGF2α, 24 h after the first
Day 9, 56 h after PGF2α	GnRH
Day 10, about 16 h after the second GnRH	Timed AI

The 56 h / 16 h timing is the Ovsynch-56 schedule (Brusveen et al. 2008), which gave more pregnancies per AI than Cosynch at 48 or 72 h in that trial. Older schedules give the second GnRH at 48 h and inseminate at 0–24 h after it (the original Ovsynch bred 24 h after it; Pursley et al. 1995). The optional second PGF2α on day 8 raised complete luteal regression and P/AI in a meta-analysis of seven trials (Borchardt et al. 2018).

Presynch-Ovsynch (Presynch-11, -12 or -14): two PGF2α doses 14 days apart, then Ovsynch starts 11, 12 or 14 days after the second PGF2α; the number in the name is that gap. Moreira et al. 2001 used 12 days (Presynch-12) and Fricke et al. 2003 used 14 days. Cows seen in heat after a presynch PGF2α are often bred on that heat and leave the protocol.

Double-Ovsynch (Souza et al. 2008): a “Pre-Ovsynch” of GnRH, PGF2α 7 days later, GnRH 3 days after that; then 7 days later a full Ovsynch.

Day	Step
0	GnRH (Pre-Ovsynch)
7	PGF2α
10	GnRH
17	GnRH (Breeding Ovsynch starts)
24	PGF2α (often a second dose on day 25)
26, 56 h after PGF2α	GnRH
27, about 16 h later	Timed AI

This matches Souza et al. 2008 (AI 16–20 h after the last GnRH; the second PGF2α dose on day 25 was not part of their trial).

Resynch programs restart Ovsynch in cows not seen in heat after an earlier insemination, usually starting GnRH a week or so before the pregnancy check. The same compliance rules apply.

On time, late, early, missed

For each scheduled step:

On time: given on the scheduled day (or within the herd’s allowed window, e.g. the same milking shift for the second GnRH).
Late or early: given, but on a different day. A PGF2α one day late shifts the whole timing and lowers conception. A GnRH given early can ovulate the follicle before it is ready.
Missed: never given. The cow either continues the protocol with a gap, or should be pulled out and restarted.
Not due: the cow left the protocol for a valid reason (bred on a detected heat, sold, died, marked DNB, found pregnant). These steps are removed from the denominator, not counted as missed.

Report missed and late separately. Missed steps usually mean a cow was not found or not sorted; late steps usually mean a scheduling or list problem.

Formula

Plain text:

Step compliance (%) = steps given on the scheduled day / steps scheduled (excluding cows that validly left the protocol) × 100

Missed (%) = steps never given / steps scheduled × 100
Late (%)   = steps given after the scheduled day / steps scheduled × 100

Cow-level compliance (%) = cows that received every step on time / cows that completed or should have completed the protocol × 100

LaTeX:

C_{\text{step}} = \frac{N_{\text{on time}}}{N_{\text{scheduled}}} \times 100
\qquad
C_{\text{cow}} \approx C_{\text{step}}^{\,k}

Where k is the number of steps per protocol. Step compliance compounds: with 5 steps (GnRH, PGF2α, PGF2α, GnRH, TAI) at 95% each, only 0.95^5 ≈ 77% of cows receive all of them on time. At 90% per step, it falls to about 59%. That is why a “90% compliant” program can still lose a lot of pregnancies.

How to pull it in DC305

DC305 has no built-in compliance report. Compliance is computed by comparing recorded protocol events against the schedule.

Protocol injections are recorded as events, for example a synch or shot event per injection with a remark naming the hormone, or one event per protocol step. Event names and remark codes vary by herd; look them up in the herd’s private dc305-vocab mapping and DC305 events.
Many herds keep a user item with the protocol start date, so that each step’s scheduled date is start date + the step’s day offset.
The timed AI itself is a BRED event, usually with a breeding-type code or remark that marks it as timed AI.

EVENTS\2SI                  list of cows and events; prompts for the date range (\S) and which events (\I)
EVENTS\2S30I                the same, starting 30 days ago
EVENTS\W                    events by day of week
LIST ID PEN ... FOR ...     the herd's shot list for a given day (from its protocol-date item)

Steps to compute:

From the protocol start date, build each cow’s scheduled steps and dates.
Match each scheduled step to a recorded event of the right type within the allowed window.
Classify each step as on time, early, late, missed, or not due (cow left the protocol).
Report step compliance by step (first PGF2α, second GnRH, etc.), by day of week and by pen or crew, because problems cluster there.

A quick proxy when events aren’t recorded per injection: the share of timed-AI breedings that fall on the protocol’s insemination day, and the spread of days to first service.

Typical range

Herd context: US Holsteins, lactating cows, freestall or dry-lot, timed AI for first service and resynch.

Measure	Typical	Goal
Step compliance (on time)	85–95%	> 95%
Missed steps	2–8%	< 2%
Cow-level full compliance	60–85%	> 85%

Effect on conception: missing the PGF2α or the second GnRH, or giving either a day off schedule, can cut pregnancies per AI substantially for that cow (often by a third to a half or more), because the cow does not ovulate at insemination.

Second PGF2α dose: adding a second PGF2α 24 h after the first in Ovsynch improves luteolysis and usually raises P/AI by a few points, but it also adds a step that must be complied with. A meta-analysis of seven trials (5,356 cows) found +11.6 points complete luteal regression and +4.6 points P/AI (Borchardt et al. 2018).

Common mistakes

Counting cows that validly left the protocol as missed. Cows bred on a detected heat, found pregnant, sold or marked DNB should leave the denominator.
Only measuring the AI step. A cow can be inseminated on time after a missed PGF2α. The insemination is compliant; the protocol is not.
Reporting one average. Break compliance out by step, day of week and pen. Weekend steps and the PGF2α that falls on a different day from the other shots are typical weak points.
Ignoring compounding. 92% per step sounds good; across 5 steps it is only about 66% of cows fully on schedule.
Unrecorded shots. If injections are given but not entered, the data show them as missed. Check the recording before blaming the crew.
Blaming the protocol. A low timed-AI CR on a herd with poor compliance is an execution problem. Fix compliance before changing protocols.