A repeat of 2011 is happening.  I really recommend that you read this in detail.  You MUST keep your goats hydrated and out of sun and in shady areas and well ventilated.  Goats are dying in this heat.  Kids are dying in utero.  If you live in the southern part of the United States, I recommend that you breed for kidding no later than mid-April.  Summers like this one can be way too hot and induce way too much stress on pregnant does.

Suzanne Gasparotto

HEAT STRESS - A Case Study at Onion Creek Ranch in 2011

Spring and summer 2011 brought to West Texas severe drought and very high heat; temperatures above 100*F have been the norm. Consecutive days of temperatures as high as 109*F with 35-40 mph of hot dry wind combined with slightly more than one inch of rain since August 2010 have produced serious problems with both animals and pastures.

Onion Creek Ranch's Tennessee Meat Goats™ and TexMasters™ have been kidding in this environment. Kidding problems started occurring in May 2011, shortly after the 109*F heat and winds took place. Although the does were maintained in controlled areas for observation and assistance if required, kidding activity was anything but normal. We never saw any indication of the does' water breaking. Cervical dilation was minimal and sometimes non-existent. When the does tried to push their kids out, contractions were too weak to accomplish birthing. We had to go in and try to pull kids, some of which required veterinary assistance to get out. When kids were pulled, quite a few were dead on arrival. Several dams died. I did not have necropsies done. In retrospect, I doubt that necropsies would have been beneficial.

I have been raising goats for 22 years and I have never experienced these problems. I started searching for whatever could possibly be the problem. My first concern was nutrition. Dystocia (kidding problems) can result from improper nutrition and can be worse during stressful weather conditions. After consulting my livestock nutritionist and my vet, we concluded that my nutritional program was appropriate and I had no calcium or other mineral deficiencies. Nevertheless, CMPK/MFO was orally drenched when does went into weak labor in an effort to improve contractions -- without success. Water conditions were rechecked; extra water was offered and put in more shaded locations. Facilities were re-evaluated and methods of feeding pelleted grain and hay were reviewed. The conclusion was that something else was causing the problems.

On Sunday, June 5, 2011, yet another doe had stuck dead kids, so I made the 100-mile round trip with her to my vet. The kids were dead but the dam was saved. She had two dead kids and one hairless mummified fetus of about 3-1/2 months of age. I preserved it in a formalin-filled jar to show to students at GoatCamp™ in October 2011.

The conclusion was HEAT STRESS. The heavily-pregnant does were struggling in this very high heat to cool themselves, and when they went into labor, we concluded that they were not able to achieve cervical dilation and then push the kids out. The possibility of using injections to assist in delivery were discussed and dismissed (dexamethasone and/or lutalyse), because unless the precise date of conception was known, then the date of delivery was also unknown, and using these medications could cause more problems than already existed. We decided that oxytocin levels must be depressed by the heat, resulting in the does' inability to deliver their kids. I soon learned that this was an incorrect assumption.

The decision was made to add extra electrolytes daily to the automatic waterers while praying for relief to this drought and heat. I was already misting the does and wetting the dirt floors down with cool water several times a day, while a large oscillating fan and a stationary box fan were simultaneously circulating the air. I was pleased that the problem was not something that I caused, but I was equally distressed that there was not much more that I could do to prevent it.

On June 9, 2011, another doe went into labor. We got two dead kids out that were still in the sac, and we saved a very tiny female. She was obviously premature, with teeth still in the gums, difficulty breathing indicated by open-mouthed panting, and she could not eliminate feces unless she was given a warm soapy water enema. But she was alive! On the evening of June 12, 2011, she began having more problems -- passing no feces that afternoon or night despite enemas -- and she was dead by 9 am on June 13, 2011. I was distraught. What did I do to cause this? After mentally beating myself up all day, I began searching for studies on heat stress on the Internet. I found a paper written in 1991 on research done on heat stress in pregnant sheep (ewes) carrying twins at the University of Nevada Reno campus by Drs. Charles E. Dreiling, Franklin S. Carman III, and David E. Brown entitled "Maternal Endocrine and Fetal Metabolic Responses to Heat Stress. " Someone had already experienced this situation and researched its causes!

According to the University of Nevada Reno study and published research done in the 1980's by Dr. Brown at the University of Illinois, this is what had been happening: Growth rates in the fetuses were retarded. For every 1*C (roughly 5/8 of one degree F) of increase in the dams' core body temperature, uterine blood flow decreased by 30%. Heavy open-mouthed panting by the dams resulted in a loss of carbon dioxide in both the dams' and the unborn lambs' blood, resulting in a pH change called respiratory alkalosis. When the ewes became alkalotic (too little acid in their blood), uterine blood flow was greatly reduced, presumably to conserve blood volume for the dam as massive dilation of blood vessels in the skin occurs to eliminate excess body heat. However, uterine blood flow is how the fetuses receive nutrition, and they were essentially being starved in the womb. In the 1991 article, accompanying this decreased uterine blood flow were 60% increases in serum oxytocin (uterine contraction stimulator) and 100% increases in antidiuretic hormone which retains water in a body that is dehydrating. Not only were the fetuses effectively not getting sufficient nutrients for growth but uterine contractions were probably being induced as well in a massive effort to retain water for maintenance of adequate blood and body fluid volumes.

In the study, Caesarian sections on the dams were performed at a constant number of days from known mating dates in order to rapidly get fetal blood and liver samples without the effects of labor. When they were delivered, the newborns were 20% smaller than the control group. When twins were delivered, one of the lambs weighed at least one-third less than the other twin. Livers in the small heat-stressed lambs had one-fourth of the protein levels of its sibling when compared to lambs from non-heat stressed dams. Muscle protein was decreased and liver enzymes were elevated. Decreased liver protein levels meant that the fetuses were receiving inadequate amounts of nutrition in utero; inadequate nutrition meant decreased storage of proteins in the liver. Elevated liver enzymes meant that the lambs' internal organs were breaking down. Heat-induced abortions (non-bacterial/non-viral) were occurring as the dams' bodies were trying to rid themselves of excess heat.

The study produced the hypothesis that "heat stress stimulates the release of maternal antidiuretic hormone and oxytocin, which reduces uterine blood flow and causes a shift in fetal metabolism from anabolic (building up*) to catabolic (breaking down*) pathways; one fetus of heat-stressed twins is more severely affected than its litter mate."

There was nothing mentioned about mummified fetuses, but I suspect that the dead kid in each of my two dams' birthings mummified because it (thankfully) stayed encapsulated in the membranes rather than exiting it, then decomposing and producing toxins which then may be killing other kids in utero and possibly the doe as well. I further hypothesize that the lack of visual observation of the dam's water breaking when parturition began could be attributed to the does' bodies attempting to retain fluids when the antidiuretic hormones kicked in.

Just as this article was going to print, I received a return call from Dr. David Brown, who of the three authors, is the one who carried on this work. He told me that this research ultimately led to solving a major problem in the chicken industry. In the summer, laying hens produced soft-shelled eggs (very thin shell) or membrane eggs with no shell at all resulting in millions of dollars of lost revenue for chicken egg producers. Research had demonstrated that open-mouthed panting chickens lose carbon dioxide from their blood and have decreased uterine blood flow where the egg shells are made -- just as the ewes did. The solution was to pump carbon dioxide from canisters into the low-pressure closed watering system with multiple water nipples. Panting hens raised CO2 levels in their bloodstreams by drinking this soda water. Voila! No more soft-shelled eggs. The watering system has to be closed because carbon dioxide would escape into the atmosphere from an open system. A closed carbonated watering source for goats would have to be used about 100 days each year when temperatures are 100*F* and above. It is not preventative but rather must be applied during times of chronic panting only.

On June 13, 2011, two dams successfully delivered two kids each on their own in the early morning (cooler) hours. However, our daytime temperatures are soaring again, so this ordeal may not yet be over. My thanks to Dr. David Brown for his assistance in understanding his study and editing this article to make sure that I described events accurately.

* definitions in parenthesis added by Gasparotto

Suzanne W. Gasparotto, Onion Creek Ranch, Lohn Texas 6/23/11

The author, Suzanne Gasparotto, hereby grants to local goat publications and club newsletters, permission to reprint articles published on the Onion Creek Ranch website under these conditions: THE ARTICLE MUST BE REPRODUCED IN ITS ENTIRETY AND THE AUTHOR'S NAME, ADDRESS, AND CONTACT INFORMATION MUST BE INCLUDED AT THE BEGINNING OF THE REPRINT. We would appreciate notification from any clubs or publications when the articles are used. (A copy of the newsletter or publication would also be a welcome addition to our growing library of goat related information!)

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