March 2, 2010

Twins, again.

Well, it's that time of year again. Breeding season arrived at Fields Quarter Horses right on schedule this year. Each year- foaling season for the Quarter Horse at our farm runs from January 1st until mid-June. Because a horse gestates on average 340 days and we do not want our foals born before January 1st, breeding season opens a month later in February. This year, we've been quite busy already breeding mares.

The first set of mares were bred on February 12th by artificial insemination. Chevy has lots of lady friends but very little actual experience when it comes to meeting, dating, or otherwise wooing the opposite sex. His first venture to the breeding shed produced semen which was used to inseminate 4 mares. Those mares had been prepped for breeding season by being housed in stalls under lights for 16 hours each day. This process causes their bodies to produce more melatonin because their eyes are tricked into thinking that the days are longer than they really are. The increase in melatonin causes the balance of their hormones to "shift" and causes them to begin producing viable (or useable) eggs on their ovaries.

So, the first mares were poised on the bring of virtual Spring, they were inseminated, and again we intervened by utilizing a special compounded drug called Deslorelin to encourage the mares to ovulate the more fertile eggs (also called follicles). With the brave Chevy swimmers (semen) on board, it was left to Mother Nature to work her magic and we waited the long 16 days to determine if we had produced pregnancies. During the 16 days while we were waiting, we stacked the deck sort of by also giving the mares oral progesterone to make sure that their hormone levels stayed at a healthy level to maintain a budding pregnancy.

Well, I'm pleased to say that Chevy's first 2011 foals are on their way. Essi, who is a notorious culprit for producing twins, has been ultrasounded with a single healthy pregnancy. We will of course be checking her again at 21 days and then breathe easier when we find a heartbeat on the new embryonic horse at 27 days. From there, it will be 10 more months of feeding and nurturing the little life.

Sabrina, on the other hand, has decided to be generous and produce twins. Unfortunately, the mortality rate of  twin foals is not very high so the best chance of a surviving foal is to eliminate one of the fetuses. Dr. Bruce Howard of Rood & Riddle visited the farm today to perform the procedure. As fascinating as the modern technology is, I am always sad at the loss of an embryo- particularly at our hands. But, I understand that it is absolutely necessary for the health of the mare and her unborn foal.

First, the vet identifies the position of the two embryos. He quickly makes a determination regarding which embryo has the best chance for survival based upon its size and position in the uterus of the mare. Frankly, it does pay to be the biggest, strongest, and have the best seat in the class. After determining which embryo will be the survivor, he isolates the unfortunate one into a different area of the uterus (if possible) and literally "pinches" it between his fingers. As I watched the little ball of genetics disappear on the ultrasound screen, I said a prayer that it would have a speedy return to horse heaven. The fluid from the dying embryo seeped around the healthy one before it was absorbed by the spongy walls of Sabrina's uterus.

To make sure the insult doesn't end up with an abortion of the survivor, we administer additional progesterone and anti-inflammatory drugs to the mare. She will be watched closely for several days but the vet felt that the procedure was pretty much textbook and the larger, healthier embryo would persevere.

So, I suppose breeding season also means that it's twin season at Fields Quarter Horses. We have good semen, good drugs, and a good feeding program. All these factors combined cause our farm to also have a high ratio of twin pregnancies. We are careful to examine the early pregnancies for any chances of twins for the safety of our mares but it is my fear that someday, we will deliver a set. I surely hope that we will not.

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