Cows, calves and veterinary

Decisions, decisions - or, what do you do when mating goes wrong?

Seasonal dairying is one of those funny things where it helps if certain things match up. Grass growth, calving cows. Grass growth, peak milking and mating. Mating non-return rate, next year's grass growth.

Exactly four weeks ago today I put an Angus bull out with the herd to take care of any cows that weren't yet in calf.

About three days ago, I looked at the board where I write up matings before transferring them to permanent, paper records, and decided it looked wrong. There were the same number of cows on it as three weeks previous. I checked against the paper records, and of eight cows that had been mated by the bull 21 days or more previously, five had returned.
The next day, 150 returned. She's now in a herd not running with the bull, and I mated her to AB. So far, the bull's got 3 out of nine.
This evening, Giant Panda returned, a few days late. The bull's non-return rate has now dropped to twenty-two percent. I'll be mating her to AB in the morning.

You see, the problem with something going wrong at mating time is that it takes at least three weeks to know that your cow isn't in calf.
On the other hand, averages can be a funny thing. My bull could be perfectly normal, and with a 100% non-return rate from henceforth, finish the season with a good normal average of 50 - 65% conceptions against services. He is finding and servicing cows effectively.
So - if I bury my head in the sand, I might discover I don't have much of a problem at all.

On the other hand, I do have at least seven - good - cows who failed to get in calf during week seven of mating. If I'm running a low fertility bull, five of those have been mated again by him in week ten, and every other cow mated in that three week period also has a very low chance of being pregnant. An average herd will have 3 - 12% of the herd not in-calf at the end of a restricted mating season. A reduced conception rate over a four week period could be disastrous in the early part of the season, annoying in the later stages.

What to do now requires no thought. I have ten or eleven straws of semen left in the AB bank. We're at the stage of mating where everything conceiving from henceforth will be an October calver - marginal at best for being profitable in a seasonal calving system. I could use up the last of the straws, leave the bull in till the tenth of January as planned on the off-chance that he succeeds in getting cows in calf, and just accept the losses if a few extra cows are empty.
That wouldn't be a *bad* plan, but it's not a good one either.
You see, there are some excellent young cows that have come in season since the bull went out. If they don't get in calf, then not only do I lose the cow and all her future potential, but next year I'll quite likely be understocked again, and unable to fully utilise the potential of the farm.

There are about five cows due to return over the next few days. The number of these that come back in-season will determine whether there is a serious problem or not, and there's easily enough semen in the bank to cope with returns for the next week. By then I'll know whether I'm looking at a blip in an average, or if it's time to move into crisis mode and do a few things that I swore would never be part of my farming practice.

a) Call the LIC district manager in the morning. Check if semen deliveries will be possible over the Christmas/New Year break - if no, it may be wise to have ten or twenty further straws delivered immediately, even if they have to go into storage till next season.

b) Unless the bull's NRR rate drastically improves, AB all in-season cows until the tenth of January (20 October calving date). Leave the bull in with the herd until the end of January (10 November calving date) unless his NRR rate really is so abysmal he might as well not be there.

These will be late calvers. But there are options for late calvers. There's not much you can do with an empty cow - cull her, sell her, attempt a 2-yr lactation, or carry her over as an unproductive cow and give her another chance to get in calf next spring. None of these are good options for a young cow on a seasonal calving farm.
If she's late, you can sell her, cull her, let her calve naturally and milk her for a few months, either encouraging her to get back in calf quickly with fertility treatments or accepting that it will probably be her last productive year. Or induce her to calve early, in the hope that she will then get back in calf early for the following year.

My farming philosophy is to minimise fertility treatments and forgo inductions altogether. But faced with the likelihood of culling a good cow - yeah, I'll go back on that. It becomes a numbers game. Ideally there would be no October calvers. In practice, I'm happy with five to ten percent of the herd, as long as nearly all calve before mid-October. When I'm looking at potentially fifteen cows in calf due late October/early November - then I think I've got a case where inducing that group to calve at seven months gestation is justified.
With a short mating, you don't have those cows - they're gone, culled as emptys.

c) This will probably be the last year that I run a single bull with my herd. Even though I don't have more cows cycling than one bull can handle (I did six weeks AB, with a good NRR), this is the second year in a row that the bull has had problems. Last year we finished up with a fairly average empty rate of about eleven per cent, but due to the bull's lameness, lost the advantage of having him grazing with the herd picking out the cows as they came on heat.
Two bulls working together reduces the risk to almost nil. A friend once insisted three were necessary, regardless of the size of herd - so that two could fight over the cow while the third got on with mating her.

Earlier this season I considered dispensing with a bull altogether and doing AB for twelve weeks each year. I decided against for two reasons:
i) Eighty-four days AB means eighty-four days of full alertness detecting heat, and no, I don't get time off. While in theory asking a relief milker to draft cows for an LIC technician is possible, in practise I find relief milkers invariably miss cows in heat and clear instructions invariably get ignored or misunderstood (not intending to insult my current relief milker, who did identify every cow according to the tail paint. Two years ago I left a boss milking his own herd for a few days. He wrote down the numbers of four or five in-season cows for me (minus the dates on which they were on heat). I checked the tailpaint of every cow on my return and added *twelve* cows to that list. Last year, another relief milker somehow failed to see and draft a heifer whose back was rubbed raw. She got in calf three weeks later.)
ii) Bulls are very good at detecting heat - better than most stockmen. They also seem to have some effect in bringing on cows that may have been non-cycling, simply by their presence in the herd. It's not unusual for a bull to sire a calf without the farmer noticing that the cow was in heat, and the cow then gives the farmer a pleasant surprise by being found in-calf with no recorded heat (or a less pleasant surprise when she has a calf later than her last recorded due date).

d) Pregnancy diagnosis. Last year I only PD'd the cows I either supected or knew were empty, or that had an unusual interval between matings. What I discovered was that every cow I thought was empty, was. Every date I changed according to when the vet told me a cow was due, was wrong. For a while, I was considering dispensing with PD altogether this year and simply culling on the basis of whether they were cycling (they pretty much all cycle, in the end, even if they're anoestrus during mating) and sticking to the dates I'd recorded from my own observation.
What changed that plan was calculating my non-return-rate and discovering that it is actually slightly higher than the experienced technicians I've monitored over the last few years. While it would be nice to think that I'm simply very good :-), there's one very important rule in farming: If everything's going right, something's going wrong. It's standard advice that if an unusually high number of cows appear to be holding to their first service, you don't believe it.
The other, rather important reason why I changed my mind and decided to PD the whole herd - and do it early - is that I've used enough dairy semen to see about 45 heifer calves next year. Since the extra pen I made in the calf shed was too wet to use at all this season, I know I can't plan on having any more than thirty calves in the rearing shed. If I'm expecting many more than that in a short space of time, I need to do something about suitable accomodation for them, well in advance of calving.
Between the option of turning them out to pasture at very young ages and finding extra housing for the extra numbers, I'm leaning towards the idea of investing in a poly-tunnel.

Although pregnancy can be diagnosed from about six weeks, to be certain I really like to leave it seven. So a good plan at this stage might be to PD every cow supposedly holding to AB around the seventh - tenth of January. Those not identifiably in calf *may* be in-calf to the bull, non-cycling or about to cycle again.
That would give me an estimate of how many heifer calves to expect next year (45 - 50% of all the cows holding to dairy AB who aren't likely to be culled for other reasons) and identify those who possibly aren't holding.
A later PD should be timed late enough to detect *all* pregnancies, but early enough to date those resulting from natural matings. Some vets can date a pregnancy up to fourteen or fifteen weeks, others only twelve - given the inaccuracy of the information last year's vet gave me, I'd aim for the lower number.
So, all cows not previously confirmed in-calf should be pregnancy diagnosed six and a half to seven weeks after the bull comes out - fifteenth to twentieth March if he's left in until the end of January. Pregnancies dated less than twelve weeks at this stage will be October calvers or later.

PD at this stage doesn't do much about getting empty cows in calf, but it does give information which is essential for making plans for next year - not least, deciding which cows to cull when the feed starts getting short in the autumn.

*

If life doen't scare you from time to time, chances are you're not doing it right :-0 The same is very true for farming. Sometimes you have to step out of your comfort zone to progress, other times you get thrown out of your comfort zone.
When something goes wrong with a programme as essential to the business as getting cows in calf, it's too late to be proactive - now you have to identify the problem and act quickly.
Just the same as if it was a drought. Staff problems. Machinery breakdown.
Things have stopped running smoothly, and it can look as if the effects are out of your hands.
But that is rarely true. I believe it's been said that the best farmers are simply those that respond to weather/market conditions a week before everyone else.

Monitor. Identify. Act.

I'm sure there are fancier ways to get that point across. But that'll do for now.

ETA At this stage about 66% of cows mated in the bull's second week out are apparently holding - so hopefully not too much to worry about. One of those cows I'm very surprised at: she's a heifer who was treated for metritis after her first cycle and failed to clear, was still discharging large quantities of pus at her last heat three weeks ago. Yet at this stage she's a few days overdue, suggesting either a miracle conception or a break in her pattern of strong, regular heats.

posted by nellta holdings @ 1:47 AM