Heat stress and preg testing

[Chocolate Cow]

I'm lost.....I have a group of 22 Angus yearling heifers that were pasture exposed from May 27 - July 27. We brought them home Saturday and I preg checked them Sunday. 6 were open. :shock: I took the bull to the vet yesterday and he tested good. Veterinarian stained the sample and checked for deads. Nothing. Testicles were good with no problems. The bull settled 16. He's a 4 year old and is only used on my heifers. Nothing got into the pasture nor did he go anywhere. These heifers have good BCS and were vaccinated in March with Bovi-Shield FP5 VL5. I took them to grass April 20 so they could acclimate from their winter feed to green grass. In 2016, I put 40 heifers with this bull and one more for 30 days and had 100% conception. Yesterday evening, 3 of these 6 heifers were in standing heat. grrrr

Only thing I can come up with is our summer was really hot & humid. I'm wondering if these opens are a result of embryo death from the heat. The pasture has 4 ponds and a well but no trees. They had salt, mineral, a protein tub, fly control. But I didn't sing to them :roll:

Any ideas would sure be appreciated.

 

[MRRherefords]

It may very well be heat stress. We had embryotic deaths due to heat this year and that can keep them from settling too.

 

[angus9259]

I suspect heat stress as well. Could be heat stress on the bull too - buddy had one that went to zero semen and came back. His vet said testicular heat stress.

That said, What's the difference between a 3 yo and 4 yo bull in weight? Some just not up for the weight?

 

[dun]

Did you do a Repro Tract Score (RTS) on the heifers before you turned them with the bull?

 

[Chocolate Cow]

Yes, the heifers had been examined by my vet. I asked him if the bull had problems with the heat, would it be a reoccurring event. He said 'No. It's something that hits a bull one year and not the next. No way to know other than pulling him part way through the breeding season and have him checked.'

angus 9259 - do you mean some heifers can't support the weight of an older bull? There was a smaller heifer in the group and she was bred. I'da bet money on her not being.

I went back and found the daily temps for June & July in my area. Average daytime temp for the 60 days he was in with the heifers was 107. :shock:

 

[dun]

If all of them had an RTS of 4-5 then I would start thinking weather/temp-humidity. May have affected the females but it may also have made the bull lethargic and disinterested. Or it could be using roundup

 

[Chocolate Cow]

I'd sure like to think there's little to no Roundup exposure, Dun. I've got a road to the north, road along the east with a pasture across that road.....actually, I'm surrounded by other pastures. There are Fall herds in the pasture south and west of me, so no bull pressure. I don't spray Roundup for weed control. There is some crop ground on north of me but it drains to the north. Guess there's always 'drift'.
I appreciate everyone taking time to offer their thoughts. This has been a disappointment for me.

 

[Ebenezer]

I'm wondering if these opens are a result of embryo death from the heat.

My bet. Several years ago there was a researcher in GA who found it to be a bigger issue than expected. For us in the east, friend In KY has seen positive relationship to little shade and more pinkeye. Not heat but in the same vein of discussing environment.

 

[Lucky_P]

CC,
At this point in time, it's all sheer conjecture.
Heat stress and embryonic death are definite possibilities. 107 is pretty doggone hot... and I'll bet that it didn't cool down much at night, so they probably had a hard time dissipating much of that heat that built up over the day.
But... just because the bull was good in 2016... and again right now... doesn't mean that something didn't happen - either to his testicles or his 'wheels' that resulted in temporary infertility &/or inability/reluctance to service those heifers for a period of time.
A semen evaluation is just a snapshot of that particular point in time... and indicates that the development process that started 60 days prior has continued with no glitches.
Chasing infectious disease problems months out is problematic, and often unfruitful. The picture gets fuzzier the farther out from the event that you get.
I'm a firm believer in incorporating LeptoHB (hardjo-bovis) bacterins into vaccination programs. I see far more opens that potentially fit the picture of a LHB problem(early embryonic death) than I do mid-to-late-term abortions that we've historically associated with Leptospirosis.

 

[Ebenezer]

Just shows that it pays to always keep heifers out of cows that have calves!

 

[Lazy M]

Just shows that it pays to always keep heifers out of cows that have calves!

If the cow didn't have a calf then there'd be no heifer to keep

 

[Ebenezer]

Just shows that it pays to always keep heifers out of cows that have calves!

If the cow didn't have a calf then there'd be no heifer to keep

A little joke about fertility.

 

[wbvs58]

I don't really buy into that heat stress, I would be looking elsewhere. I am a believer that some heifers just don't allow the bull to do his job especially yearling heifers. Some bulls will not let them get away and wrap their arms around them and hook them in while others will just expect them to stand there while they just jump on and try to do their job.

Ken

 

[TexasBred]

I'm lost.....I have a group of 22 Angus yearling heifers that were pasture exposed from May 27 - July 27. We brought them home Saturday and I preg checked them Sunday. 6 were open. :shock: I took the bull to the vet yesterday and he tested good. Veterinarian stained the sample and checked for deads. Nothing. Testicles were good with no problems. The bull settled 16. He's a 4 year old and is only used on my heifers. Nothing got into the pasture nor did he go anywhere. These heifers have good BCS and were vaccinated in March with Bovi-Shield FP5 VL5. I took them to grass April 20 so they could acclimate from their winter feed to green grass. In 2016, I put 40 heifers with this bull and one more for 30 days and had 100% conception. Yesterday evening, 3 of these 6 heifers were in standing heat. grrrr

Only thing I can come up with is our summer was really hot & humid. I'm wondering if these opens are a result of embryo death from the heat. The pasture has 4 ponds and a well but no trees. They had salt, mineral, a protein tub, fly control. But I didn't sing to them :roll:

Any ideas would sure be appreciated.

Just a thought but are you always 100% right with your preg checking? I use to think I was pretty darn good until I missed one by 8.9 months. :lol2: :nod:

 

[Chocolate Cow]

I ultrasound. And, it's only as good as the person running the probe. A pregnancy is easy to detect. I always take more time with an open because it's a financial thing and possibly the sale of a cow. Pregnancies 35 days to 6 months are straight forward. 8-9 months take a little more effort.

I have a fall herd, so after testing the bull in question, I put him back with this group. I'll put the re-bred heifers into the fall herd. Amazing-that sucker won't mix with them. He's standing in the pen. They go out to graze, come in for water, one or two will ride him but he doesn't pay any attention. So-I own a LBGTQ bull? :???:

 

[angus9259]

So-I own a LBGTQ bull? :???:

Happens more often then you think. Some version of low libido I reckon.

That said, my money is on the bull dynamic. Heat stress or injury to the bull combined with small heifers that may not want to be crushed under his weight. Eventually it becomes not worth the work (especially at 107 degrees).

 

[Chocolate Cow]

a few pictures of the heifers

 

[LocustDaleCattleCompany]

We have lower conception rates with our two Spring herds than our two Fall herds. Like 80-85% compared to 95-100%. We have tried everything in the world to improve conception with the Spring herds but we (vets and local guys around me) keep coming back to heat stress on the bulls. Pretty hot and humid for the boys in June and July. Same bulls used for Spring herds and Fall herds and plenty of redundancy (usually an extra bull put in with each herd). BSE performed 1 to 3 weeks on bulls every time before turn out. And breeding heifers has its own challenges with conception.

 

[gizmom]

My bet would be on heat stress.

Gizmom

 

[Chocolate Cow]

Thanks everyone for offering suggestions. I realize I may never know the cause of the high percentage of opens. I have bought a new bull to put on this next years heifers and we're going to build some sort of shade in this pasture for cattle comfort. Other than that-it's business as usual. :deadhorse: :tiphat: