Lesson 8 - Parturition and Related Problems and Illnesses

Lesson 8: Parturition and Related Problems and Illnesses Student Learning Objectives (Enablers) As a result of this lesson, the student will … 1. Identify gestation lengths of livestock. 2. Understand the physiological changes that occur prior to, during and after delivery of fetus. 3. Describe malpresentations commonly found during delivery. 4. Demonstrate the correct placement of obstetrical chains on a calf. Time: Instruction time for this lesson: 50 minutes. Resources • Scientific Farm Animal Production, Taylor, 4th Edition (MacMillan) • University of Nebraska Cooperative Extension, http://ianrpubs.unl.edu/Beef/g539.htm • http://www.usask.ca/wcvm/herdmed/applied-ethology/articles/maternal.html • http://www.animal.ufl.edu/yelich/3316/Notes/WWWRuminatPartDystocia.pdf Tools, Equipment, and Supplies • Timer/stopwatch • Overhead projector or computer with projector • Instructor copy of AS U5 L9 PowerPoint (will need transparencies if not using PowerPoint) • 1 copy per student of AS U5 L9 Student Mission Worksheet • 1 copy per student of AS U5 L9 Student Evaluation • Board for obstetrical chain placement activity (preparation directions - in the review section ) • Obstetrical chains & handles • Fun reward for opening “mission” • Student notebooks • Writing tools Key Terms: The following terms are presented in this lesson and appear in bold italics: gestation dystocia placenta parturition cesarean section cotyledons Interest Approach This introduction challenge will get students thinking about gestation and parturition. The objective of this activity is to have students quickly find the gestation lengths of the species listed on the challenge sheet. Variations can be made to the rules to fit the available resources. Variations may include use of only textbooks, combination of textbooks and Internet or any other available resources. Please leave the worksheets I am handing out to you face down on the table. Give each student worksheet Student Mission Worksheet Objective 1: Identify gestation lengths of livestock. We are going to start today with a mission. Your mission is to find the gestation lengths of the species listed on the sheet I have passed out. You may accomplish this mission using the animal science textbooks or the Internet. I would suggest that the textbook be your offense, but you can decide your own plan of action. When I say “action” you will have 5 minutes to accomplish this mission. At the end of five minutes, you will immediately sit back down in your seat and turn your paper over. Be sure to put your name on the paper. It is required that you complete this mission in silence. Upon the completion of the mission, the student or students with the most correct answers will receive _____________. Are there any questions as we begin? Okay – good luck on the mission and “action”. Carefully time students to exactly five minutes to add to the excitement. Be sure they work independently. Time – please put your mission tools away and return immediately to your seat with your paper face down. Good job working on this mission. Let’s see how the results come out. Give your paper to the person on your right. We will go through the gestation lengths and the person with the most correct will be congratulated. Please mark the correct answers with a “c” and leave the incorrect answers unmarked. Is everyone ready? Display PowerPoint slide #2-3. Go through and discuss the lengths and months. Please count the number of correct answers and circle that number at the top of the paper. Who has a paper that got all nine correct? If no one does – continue the countdown until you determine a winner. Be sure to have enough of whatever the prize is for the entire class incase they all succeed on their mission. Cheap, small pieces of candy do wonders! Please pass the gestation challenge sheets back to their correct owners. Think about the relationship between the sophistication of the animal and its gestation length. Please listen to the following scenario taken from the log of a veterinarian. “Most cows are able to calve on their own. When there is difficulty, most farmers are capable of assisting the cow with the delivery. When that fails, they call the veterinarian for help. One notable calving call came three years ago. The farmer told me that she had reached into the cow in an attempt to determine the problem. She told me that she was confused, because all she felt was this "thing." Now I was confused. Her description did nothing to tell me what she was touching when she reached inside the cow. I drove to the farm, wondering what I was going to find. Even someone with limited experience is able to tell me if they can feel a hoof or a nose. This caller did not recognize anything she was feeling. I cleaned the cow and reached through the vulva and into the uterus. I have helped with hundreds of calvings, so I was confident that I could explain what was occurring. As my hand finally reached the calf, my first impression was exactly the same -- all I felt was this "thing." She was right; it did not feel like a hoof, a nose, a rump or a back. I had to investigate more thoroughly. Reaching in as far as my arm could go, I was able to feel more parts. Unfortunately I now knew what had happened, but I also knew that I was in for a lot of work. I was finally able to feel a leg, but I also felt loops of intestine and a heart! When I felt the heart, I knew that the calf was inside out. This calf had a condition called schistosomus reflexus. Display slide #4. The deformity of the calf prevented a natural delivery. With the assistance of the farmers, I performed a Cesarean section -- surgical removal of the calf from the cow. We removed the calf through a large surgical incision on the left side of the cow. The cow stood through the entire procedure. It is difficult to explain what the calf looked like. The calf was basically turned inside out lengthwise. Instead of the legs pointing downward from the spine, they were pointing upwards. The skin was folded upwards as well and the internal organs were all exposed. The calf was dead at birth, but the cow did well and actually bred back to have a normal calf the next lactation.” The above excerpt is obviously a rare occurrence. We are now going to look at the various aspects of parturition. Display slide #5-8 Note important aspects of each picture. Presentation, etc. Summary of Content and Teaching Strategies Objective 2: Understand the physiological changes that occur prior to, during and after delivery of fetus. **A majority of this content text is taken directly from a publication from the Nebraska Cooperative Extension, Institute of Agriculture and Natural Recourses, University of NebraskaLincoln. Written by Gene H. Deutscher, Extension Beef Specialist and Donald B. Hudson, Extension Veterinarian. Obtained on the web page listed in the references section. Used with permission of the publisher (1/6/05). Successful calving is essential for cattle producers. Calves are the source for replacement animals for the herd and the source of a marketable product for the producer. Six to ten percent of all calves born in beef cow herds in the U.S. die at or soon after birth. Approximately half of those deaths are due to calving difficulties. This multi-million dollar annual loss is second only to losses from cows failing to conceive. Display slide #9. There are several hormonal changes that take place as parturition approaches. Progesterone levels decline and estrogen levels increase. The increase of estrogen levels prepares the uterus for delivery. The fetus releases a hormone called cortisone. This hormone stimulates the beginning of the birth process. Parturition or delivery of the newborn occurs normally at a point when the fetus is capable of surviving on its own. Display slide #10. Normal calving is divided into three general stages. Those stages are preparatory, fetal expulsion and the expulsion of the placenta or afterbirth. The time interval of each stage varies among types and breeds of cattle and among individuals of the same breed. Display slide #11. The preparatory stage will last from two to six hours. During pregnancy, the fetal calf is normally on its back. Just prior to labor, it rotates to an upright position with its forelegs and head pointed toward the birth canal. This position provides the least resistance during birth. Toward the end of gestation, the muscular lining of the dam's uterus increases in size, this aids in delivery of the calf. In the preparatory stage, the cervix dilates and rhythmic contractions of the uterus begin. Initially, contractions occur at approximately 15-minute intervals. As labor progresses, they become more frequent until they occur every few minutes. These contractions begin at the back of the uterine horn and continue toward the cervix, forcing the fetus outward. Any unusual disturbance or stress during this period, such as excitement or even movement, may inhibit the contractions and delay. At the end of the preparatory stage, the cervix expands allowing the uterus and vagina to become a continuous canal. A portion of the placenta (water sac) is forced into the pelvis and aids in the dilation of the cervix. This water sac usually ruptures and the membranes hang from the vulva until stage two. Display slide #12. Stage two or the delivery stage should last one hour or less. This stage begins when the fetus enters the birth canal, and usually occurs while the cow is lying down. Uterine contractions are now about every two minutes and are accompanied by voluntary contractions of the diaphragm and abdominal muscles. Surrounded by membranes, the calf's forelegs and nose now protrude from the vulva. After the nose is exposed, the dam exerts maximum straining to push the shoulders and chest through the pelvic girdle. Once the shoulders have passed, the abdominal muscles of the calf relax, and its hips and hind legs extend back to permit easier passage of the hip region. The calf is normally born free of fetal membranes (placenta), because they remain attached to the cotyledons or "buttons" of the uterus. This insures an oxygen supply for the calf during birth. Upon passage through the vulva, the umbilical cord generally breaks, and the lungs become functional. Delivery is normally completed in one hour or less. Special assistance is warranted if this stage goes beyond two to three hours. Display slide #13. The final state is the cleaning. The caruncle-cotyledon, or button attachment between uterus and placenta, relaxes and separated after parturition. The placenta is then expelled by continued uterine contractions. Cows normally expel the placenta within two to eight hours. These three stages are considered normal for most cows. Heifers may vary in length and actions during some of these stages as they tend to be more nervous. However, whether working with a heifer or cow, if the stages are severally out of place or not progressing, assistance may be needed. Check for understanding using the Me, You, Us e-Moment. I want you to silently think about why the calf is normally born without the placenta covering. You are going to have a moment to think about your answer. Wait for about a 30 seconds. I know want you to turn to the person on your left and discuss the answer to this question. Give them about 1 minute to discuss. Now I would like for one or two groups to tell the class their answers. Call on several groups, even if the first gets the correct answer in order to check for understanding. Great job, we are now going to continue with the lesson. Objective 3: Describe malpresentations commonly found during delivery. About five percent of the calves at birth are in abnormal positions, such as foreleg or head turned back, breech or rear end position, sidewise or rotated, etc. This requires the assistance of a veterinarian or an experienced herdsman to position the fetus correctly prior to delivery. If fetal position cannot be corrected, the veterinarian may have to perform a caesarean section. Display slide #14-15. Preparing for Calving Assistance Normal delivery should be completed within two to three hours after the water sac appears in heifers, and one to two hours in cows. If prolonged, the calf may be born dead or in a weakened condition. Since timing is vital to providing proper assistance, frequent observations are a must. Assisted deliveries should not be attempted without proper preparation of facilities and equipment. A clean, well-lighted maternity stall with head catch facilitates examination. Clean pulling (OB) chains and handles should be placed in a bucket of water with disinfectant before use to reduce bacterial contamination. Disinfectant, soap and lubricant should be in plastic squeeze bottles to enhance use. Check with your veterinarian for advice on when to assist a cow alone and when to call him. Experience will help determine if the calf can be delivered with assistance or if a caesarean is necessary. Determination is usually made on initial examination. The goal is to deliver a live calf from every cow. Steps in Calving Assistance Display slide #16. 1. After observing a delay in delivery, a pelvic examination should be done to determine the extent of cervical dilation. The cow's vulva and rectum should be scrubbed, in addition to your hands and arms, and a plastic shoulder length OB sleeve worn. 2. Determine the position of the fetus. If it is in an abnormal position, experience and judgment must be used to determine if a correction can be made or if professional help should be summoned. Display & Discuss slides #17-19. Display slide #20. 3. Examine the size of the calf relative to the birth canal. A large calf forced through a small pelvic opening may result in death of the calf and injury (including paralysis) to the cow. If this examination is made when the head and front feet are still in the birth canal, the opportunity for a successful caesarean section exists. Display slide #21 4. Attach the obstetrical (pulling) chains to the front legs of the calf, placing the loop of each chain around each leg. Then slide the chains up on the cannon bone two to three inches above the ankle joints and dew claws. Make sure the chain pulls from the bottom of the leg (dew claw side). Display slide #22 5. Attach the obstetrical handles and pull gently, making sure the chains have not slipped. Although some calves can be delivered by pulling both legs evenly, it's usually best to alternately pull on one leg and then the other a few inches at a time. This is called "walking out the shoulders." Display slide #23 6. Once the head and shoulders are exposed, pull the calf downward at a 45° angle, or nearly parallel with the rear legs of the cow. This tends to raise the calf's hips and lessens the chance of hip lock. 7. "Hip lock" can be a problem serious enough to cause loss of the calf. If this happens, push the calf back a short distance and rotate the calf a half a turn and pull downward and forward between the cow's legs. If the cow is lying down, roll her on her back and pull the calf forward over the udder between the hind legs. Make sure the calf begins breathing normally as the umbilical cord will be pinched closed. Call your veterinarian if the hip lock cannot be readily delivered. 8. Posterior presentations (backwards calf) occur in less than five percent of calves born. The posterior presentation is a problem because the calf's hind legs and hips do not dilate the cervix as well as the front legs and head. Due to premature rupture of the umbilical cord, early assistance and rapid delivery is needed. A backwards calf in the setting position with feet and legs up under him (breech presentation) must be detected early in labor and corrected. Cows will start labor but nothing will show externally except occasionally the tail of the calf. If not detected, labor will cease and will not start again until the calf is emphysematous three to seven days later. 9. Cows with torsion of the uterus (posterior uterus and cervix twisted) will act similar to cows with a breech presentation; however, they will usually show much more pain. On examination, the calf is difficult to palpate and the twisted opening can be determined. If detected early, the torsion can be corrected or a caesarean performed to obtain a live calf. 10. A calf puller should be used correctly and only by experienced people. A calf puller can apply traction equivalent to the pull of seven men. First examine the cow, making sure the calf is in the proper presentation and position, lubricate the vagina, and then apply gradual traction. If no progress, a caesarean may be needed. Excessive traction may kill the calf, traumatize the cow and both may be lost. Display slide #24. 11. Correcting abnormal presentations and positions after extended labor usually requires professional help. Remember: be clean, learn your capabilities and learn when to call for help. Starting the Calf Display slide #25-26. Once delivered, clear any mucus from the calf's mouth and throat with your hand. Then, if necessary, stimulate the calf to breathe by either rubbing it briskly, tickling the inside of the nostril with a straw, slapping it with the flat of the hand, or suspending it briefly by its rear legs to allow drainage of fluid from the lungs. Artificial respiration can be applied to the calf as follows: place a short section of garden hose into one nostril, hold mouth and nostrils shut so air enters and leaves only through the hose; then alternately blow into the hose and allow expiration of air. Repeat at five to seven second intervals until the calf begins to breathe. Another method is to alternate pressure and release on the rib cage. Commercial respirators also are available and may be a wise investment in larger herds. Potential Post-Delivery Problems Display slide #27. Uterine Prolapse. This is an inversion of the uterus that can occur following calving. Prolonged labor, difficult birth, excess traction and subclinical milk fever are predisposing factors. Uterine prolapse should be treated as an emergency. Contact a veterinarian for treatment and necessary drugs. Cull heifers or cows that prolapse because of the probability of it happening again. Display slide #28. Retained Placenta. The placental membranes are normally expelled within two to eight hours after birth. Occasionally, however, they fail to separate from the uterus. If not treated, this condition may pose a health threat to the cow and cause problems in rebreeding. The reason for retained placentas is not known, but high incidence may indicate a disease problem. They also commonly accompany difficult births, multiple births, short gestations and bull calf births. Research has shown that manual removal of retained placentas will decrease fertility. The recommended treatment is to wait for about 48 hours after birth and then give injectable antibiotics along with uterine boluses or uterine infusions. Observe the cow closely for swelling of the vulva or signs of illness. Review/Summary Objective 4: Demonstrate the correct placement of obstetrical chains on a calf. Obtain set of obstetrical chains and handles. Prepare a 2”x2” or 2”x4” piece of lumber about 3 feet long to substitute for a calf’s leg. One end of the board should have a v-shaped notch to simulate a calf’s front hoof. As our last activity today, we are going to practice placing obstetrical chains on a simulated calf’s leg. Use the Me, You, Us e-Moment first to prepare students to conduct this activity. First, I want each of you to silently remember how to place the chains on the calf’s leg. Give them 30 seconds to think about their answer. Now, I want you to grab a partner and discuss how you plan to place the chains on the leg. Allow 30 seconds for discussion. Now, I would like one group to volunteer to be first to demonstrate the correct placement. Allow the first group to demonstrate to the entire class. Great job. Now each group is going to take a turn at this process. Continue until each group has gone. Be sure to encourage and congratulate each group. A variation to this review could be to have multiple boards or another way of simulating a calf. Application Extended classroom activity: Take a field trip to a local ranch to view a calf delivering if timings are possible. Arrange to take or get a video of a calf being born or of a C-section being performed. There are various videos available for purchase through curriculum companies on this topic. FFA activity: Take an educational tour to a veterinarian’s office to see where they would do a Csection and other tools they may use. A tour of ranch during calving would also work. SAE activity: Have a student who has livestock be involved in the parturition process. They can report to the class or take a video to share with the class. Evaluation Use the Student Evaluation. Answers to Assessment: 1. Year 2. Cattle = 279-292 (usually 283)(9 months) Sheep = 144-155 (5 months) Horses = 330-342 (11 months) Pigs = 112-115 (3 months, 3 weeks, 3 days) Goats = 145-155 (5 months) 3. Physical = thick mucous discharge from vulva, loosening of ligaments around the tailhead, fullness and distention of the udder and teats, swilling or distention of the vulva Behavioral = agitation, restlessness, frequent urination and defecation, lifting of the tail, kicking at the right side with hind foot, walking backwards 4. True 5. Calving difficulty 6. Estrogen 7. True 8. 3 9. born feet first, with the head location on top of the knees Name: ___________________________________ Date: ___________________ Average Length of Gestation **To find the average in months, average the days and round to the closest month. Species Length in days Cattle (Bovine Goats Sheep (Ovine) Pigs (Porcine) Horse (Equine) Dog Cat Rabbit Elephant Number correct: ________________________________ Average in months** Name: ___________________________________ Date: ___________________ Parturition Student Evaluation 1. Both dairy & beef producers expect cows to produce a calf each ______________. 2. How long is the gestation period for: a. b. c. d. e. Cattle ___________ Sheep ___________ Horses __________ Pigs ____________ Goats ___________ 3. List two physical and two behavioral signs of calving seen prior to delivery. 4. Both beef & dairy producers can breed cows to calving ease sires to reduce in incidence of dystocia. True / False 5. What is dystocia? 6. What hormone prepares the uterus for delivery? 7. The fetus releases a hormone which starts the birthing process. True / False 8. How many stages does parturition have? _____________ 9. Describe the normal presentation of a calf at birth.