Prostaglandin programs for milkers
Modified why wait (Six day AI and PG)This is a tried and true program that is recommended for most herds. All cows are inseminated when they show signs of heat. Cows that have been calved four weeks and have not been joined are injected with PG.
| Days 1-6 | AI cows as usual. |
| Day 6 | Inject only cows that haven't been joined And that have been calved > 4 weeks |
| Days 6 - 12 | Join cows as they come on heat. Most cows should come on during days 8 - 10. |
| Day 14 | Vet check any cows calved > 30 days that haven't been joined. |
Why wait program
Premating heats are collect for a period of 11 days prior to the start of mating. Cows are injected with PG six days after they are seen on heat and they will cycle within the first 10 days of mating. Cows are inseminated when they are on heat. This program is time consuming but only cows that are cycling will be treated.
For both the Modified why wait and why wait programs cows need to be already cycling. About 40% of the herd calved greater than 30 days will be treated in a why wait program, while 70% of the herd will be treated in a modifed why wait program.