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Reproductive Management of Meat Goat Operations

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1 Reproductive Management of Meat Goat Operations
Fred Hopkins-Dept of Large Clinical Sciences and Animal Science-UTK Kyle Rozeboom- Dept of Agriculture and Natural Resources-UTM

2 Goats Are Generally Really Good At Reproduction!

3 Reproduction is the most important factor that determines the profitability of a meat goat operation. Main goal for meat goat production: Optimum litter size (2-3 kids) with a high weaning percentage Low death loss.

4 The purpose of the reproductive management section is to provide information that will help improve the reproductive performance and consequently, the profitability of meat-goat operations.

5 The Structure and Function of the Reproductive System of the Buck and Doe
A thorough understanding of the male and female reproductive tract is important for any producer as they try to improve the reproductive rate of their herd.

6 Reproductive Organs of the Buck
Scrotum Testicles Epididymus Accessory sex glands Vas deferens Penis

7 The Scrotum Two-lobed sac that encloses the testes.
Its main function is in temperature regulation. Cremaster muscle raises and lowers testes Improper scrotal function and poor testicular distention during hot weather may lead to temporary infertility in bucks During periods of cold weather, the smooth muscle that lines the scrotum, in conjunction with the cremaster muscle that surrounds the spermatic cord, contracts and causes the scrotum to draw the testicles closer to the body. During periods of hot weather, these muscles relax allowing the testicles to distend down away from the body. The surface of the scrotum stretches, allowing a greater surface area. The surface contains both sweat and sebaceous glands (oil producing gland of the skin). Evaporation of the excretions of the glands cools the surface of the scrotal tissue and the testicles.

8 Testicles The primary sex organ of a buck and weigh about grams Suspended in the scrotum outside the body Two main functions: Produce Sperm Male hormone testosterone. Failure of one or both testes to descend into the scrotum is known as cryptorchidism. In mature bucks, they may change in size during the breeding season.

9 Epididymis Carries the sperm from the testicle to the vas deferens then to the penis. Sperm continue to develop (mature) in the epididymis and are stored there.

10 Vas Deferens Primary function is to move sperm into the urethra at the time of ejaculation. Removing or closing off a section of the vas deferens is known as a vasectomy. In vasectomized animals (teaser bucks) the animal still produces testosterone and sperm cells Prevents the passage of sperm from the epididymis to the urethra. It is a slender, muscular tube that runs from the tail of the epididymis to the neck of the bladder, where it joins the ampulla and accessory sex glands.

11 Penis Main function is to deposit semen in the female reproductive tract. It also serves as the passage for urine to the exterior. Sigmoid flexure (S-shaped portion) straightens upon erection; allows for extension In the non-erect state, the glans of the penis is contained in the sheath Mating time is very short in bucks. Intromission usually lasts less than 5 seconds. Bucks will generally throw their head back at ejaculation.

12 Accessory Sex Glands Includes the ampulla, seminal vesicles, prostate gland and the bulbo-urethral gland Function together to secrete fluids that make up seminal fluid. Sperm cells are suspended and transported within this seminal fluid Normal seminal volume during ejaculation for a buck is ml, with a concentration of billion sperm cells/ml. Seminal fluid provides a medium for sperm transport, as well as providing energy substrates, buffers and nutrients needed to assure sperm cell motility and survival within the vagina and female reproductive tract

13 Reproduction in the Doe
Female serves several functions in reproduction: 1. Provide ova (eggs) 2. Provide proper environment for fertilization 3. Nurture the embryo/fetus (gestation) 4. Deliver fetus to exterior 5. Feed the young goat (lactation) 6. Provide for proper behavior patterns Attracting male and mating Demonstrating maternal functions

14 Reproductive Organs of the Doe
Ovaries Oviducts Uterus Cervix Vagina Vulva

15 Ovaries Have two principle functions: 1) production of eggs (ova)
2) secretion of female hormones (estrogen and progesterone) The ovary differs from the testicles in that they only produce 1-3 eggs per cycle near the end of the heat period.

16 Oviducts (fallopian tubes)
Provide the site of fertilization and early embryo development before the embryo passes to the uterus. Transport the ova from the ovary to the site of fertilization which occurs midway down the oviduct. At the same time, moves the sperm cells in the other direction towards the ova from the uterus.

17 Uterus Small muscular organ that provides protection and nourishment for the developing embryo. It consists of a body and two uterine horns Inner lining of the uterus is made up of many button-like projections known as carunucles Transfer of nutrients between the doe and the developing embryo takes place via the placenta. caruncles (attachment sites for the placenta)

18 Cervix Muscular canal-like structure that provides closure to the uterus of a doe. Protects the uterus during pregnancy. During breeding, the cervix also assists the movement of sperm from the vagina to the uterus. The cervix is tightly closed and sealed during pregnancy. Cervix also acts as a sperm reservoir and prevents the transport of damaged or dead sperm cells to the uterus

19 Vagina The site of semen deposition by the buck during natural mating.
Once deposited, sperm cells are transported into the cervix and seminal fluid is either absorbed by the vagina or expelled.

20 Vulva The external opening of the female reproductive tract.
It serves as the entrance for the penis during breeding and is the end of the birth canal during parturition. It is the opening for both the urinary and genital tracts.

21 Estrous Cycle Goats are classified as seasonally polyestrous.
This means that does have multiple estrous cycles only during certain periods of the year. This period normally occurs during the fall in goats. Normally 21 days in length and can range from days.

22 Estrous Cycle The estrous cycle of a goat can be broken down into four periods: Estrus Metestrus Diestrous Diestrus.

23 Estrus Estrus is the period of sexual receptivity where the doe will stand (standing heat) to be mated by the buck. Lasts around 30 hours in a doe but can range from hours. Rapid tail wagging, mounting and bleating in does are all secondary signs of estrus in does. Ovulation of 1-4 ova usually occurs at the end of estrus or few hours after estrus ends (metestrus). During estrus the female is under the control of estrogen and will display female mating behavior.

24 Metestrus Metestrus begins at the finish of estrus.
It will normally last for 3-5 days. This is the period where the beginning formation of the corpus luteum (C.L.) takes place. Ovulation can occur during this phase in does. The C.L. is responsible for the secretion of the hormone progesterone. Progesterone is considered the hormone of pregnancy and is responsible for maintaining a pregnancy in does that have conceived.

25 Diestrus Diestrus lasts between 10-14 days and follows metestrus.
During this period the C.L. is fully functional and the secretion of progesterone is at its greatest point

26 Proestrus Proestrus lasts from 2-4 days.
Gradual increase in sexual behavior and receptivity By day 17 the endometrial lining of the uterus can recognize that no embryo is present. This causes a release of prostaglandin, which lyses(removes) the C.L. The C.L regresses, removing the doe’s source of progesterone. The doe now comes under the control of estrogen, which is being released by the ovary. Rapid follicular growth occurs and the doe begins to exhibit behavioral symptoms of the approaching estrus.

27 Factors Affecting Reproduction
Many factors affect reproductive efficiency in the goat. Fertility and prolificacy of the male and the female is determined by many genetic and environmental conditions.

28 Factors Affecting Reproduction
Puberty Seasonality Libido Heredity Age of dam Temperature Nutrition

29 Puberty The age at which an animal is capable of releasing gametes (spermatozoa and ova) and copulating. Can occur from 4-20 months of age. Influenced by factors such as breed, size, crossbreeding, inbreeding, health, nutrition and season of birth. Most doelings reach puberty by the time they reach 2/3 of their expected mature body weight and are bred in their second year of life. Bucks normally reach puberty at 4-6 months of age and doelings at 5-7 months of age. Larger breeds tend to be slower to reach sexual maturity than to smaller breeds. Within a breed, those goats that grow faster tend to reach puberty more quickly than slower-growing contemporaries.

30 Seasonality Considered short-day breeders.
Normally, September through January is the season of peak breeding activity In seasonal breeders, both males and females are affected by photoperiod (the duration of an organism's daily exposure to light) with each showing the greatest fertility during the fall breeding season (short daylight length). This means they are in anestrus (an interval of sexual inactivity)during the spring and summer, and only cycle and breed during the fall when the days are getting shorter. Breeding season begins when the ratio of daylight to darkness begins to decrease and usually ends when the ratio of daylight to darkness is nearly equal. During the spring and summer, bucks will often experience a reduction in sperm production, and a higher incidence of abnormal sperm cells. In some cases, bucks will become sexually inactive during the spring and summer.

31 Libido Buck activity and fertility play a major role in the reproductive rate of a doe. A strong libido is necessary for a buck to breed a high number of does during the breeding season. Factors such as body condition, genetics, environmental temperatures, and disease and parasites affect libido. It is important to maintain an acceptable buck-to-doe ratio (1:50 or less is recommended for mature buck). There also appears to be an advantage to running bucks in groups versus alone. Exceeding this ratio may lead to a buck experiencing sexual exhaustion, leading to decreased libido and increased health and physical problems. Body condition is also closely related to libido, as bucks that are obese, thin or undernourished have decreased libido.

32 Heredity As in other species, some breeds and genetic lines of goats produce more multiple births than do others. Nubian goats, for example, are well known for prolificacy and commonly give birth to triplets. Also, within a herd selection of replacements based on the dam’s ability to produce twins can increase the overall prolificacy of a goat herd. It has been shown that bucks from more prolific breeds appear to be more fertile than those from less prolific breeds.

33 Age of dam Age affects the reproduction rate of does.
A doe increases in fertility and prolificacy as she approaches middle age (5-7 years). Middle-aged does produce a higher number of twins than do 2-year old does. It is recommended retaining these does in your flock as long as they remain functional and sound in their structure and mammary system.

34 Temperature In the doe, temperatures above 90 degrees F for an extended period of time can decrease embryo survival and retard fetal development. High temperatures in latter gestation may cause smaller, weaker kids to be born. Lower sperm concentration, decreased sperm motility and a higher number of dead and abnormal sperm are all related to heat stress in bucks. Extended periods of exposure to temperature above 100 degrees have been shown to cause bucks to become less fertile. The mortality rate of embryos is especially high if does are subjected to these high temperatures from breeding to 8-10 days post breeding. Fat does or those on excessive feed consumption are generally more affected by heat stress Heat Stress Damage to the buck is not usually permanent and the bucks are usually fertile after 4-6 weeks of cooler temperatures.

35 Temperature To counteract heat stress
Provide good shade and proper air circulation to keep bucks and does comfortable. Minimize activity by not working goats during periods of excessive heat. During breeding season it may also be necessary to keep bucks penned up in the shade in a cool place up during the daytime when the temperature is at its greatest, and only allow the bucks to breed at night. This will minimize activity and lower the affects of heat stress on the buck.

36 Nutrition Reproduction of the doe can be enhanced by a well-managed feeding program. Doe size is determined by nutrition and genetics Larger does in a herd are more likely to produce multiple births than smaller, under-nourished does Proper plane of nutrition important throughout gestation to help build body condition reserves; maintain pregnancy; and ensure healthy, vigorous kids at birth Does that are thin, have a mineral imbalance or in a negative plane of nutrition (losing weight) will be more likely to have lower pregnancy rates, fewer numbers of multiple births and weaker kids than those with a stable or increasing plan of nutrition. Bucklings on a high level of nutrition will reach puberty earlier than those on an inadequate diet. Testicular size is also related to body growth and development. Research has shown that the testicular size of buck kids is positively correlated to the ovulation rate of their doe siblings.

37 Flushing Has shown to increase prolificacy in thin does
Flushing is an increase in the doe’s plane of nutrition 2-8 weeks prior to breeding season so that the doe is in a gaining state before and during estrus Shown increases in litter sizes Flush doe by turning out on a high-quality, pasture or feeding lbs of grain per head per day Flushing will improve ovulation rate, which can result in a percent increase in the number of kids produced in a herd Responses to flushing are greater in does that are thin to moderate in body condition, no response in fat ewes.

38 Gestation In goats the gestation length ranges from days, with 149 as standard. Influenced by genetics, maternal and fetal factors. During gestation, many changes must take place for the doe to prepare herself and the offspring for parturition. Inadequate nutrition of the doe, especially in late gestation, can result in weak kids and a higher death loss. It has generally been observed that younger does will have shorter gestation terms than older does. It has been shown that singles tend to be carried longer than multiple births and males longer than females A doe must be provided the proper nutrition and health management

39 The Normal Reproductive Characteristics Does
TRAIT AVERAGE RANGE Age at Puberty (mos) Estrous Cycle Length (d) Duration of Estrus (hrs) Ovulation After Estrus Beginning (hrs) Gestation Length (d) Litter Size Breeding Weight % of Adult Wt

40 The Normal Reproductive Characteristics Bucks
TRAIT AVERAGE RANGE Age at Puberty (mos) Breeding Age (mos) Breeding Ratio (Mature Buck) : :35-60 (Young Buck < 1yr. Old) 1: :10-25 Daily Sperm Prod. (billion) Ejaculate Volume (ml) Ejaculate Conc. (billion/ml)

41 Heritability of Important Goat Traits
*Age at 1st kidding=50% *Multiple births=15% Weaning weight=45% Weight at 7 mo.=60% Mature body weight=50% *Milk yield=50% Stature=50% Carcass weight=45-50% Quality grade=40% Ribeye area=40 to 45% Cutability=25 to 30% Muscling=40 to 45% Notice that a couple of these traits(*) are related to reproduction, though most are not. Improvement in reproductive performance is usually best accomplished by improved management.

42 Selecting a Breeding Buck
Pedigree Growth traits Multiple births Conformation Avoid inbreeding, thin or fat bucks Avoid bucks with birth defects Scrotal circumference is the most important reproductive trait for selection Reproductive traits are not usually a part of selection of breeding animals.

43 Breeding Soundness Evaluations in Bucks
Done with newer purchased bucks or herd breeding problems Physical Examination Exam of the reproductive tract Scrotal Circumference Semen analysis Volume=0.5cc Concentration = million per ml Motility=70% Normal morphology=80% This is not often done on bucks except when a problem with pregancy rate is encountered. Scrotal circumference relates well to daily sperm output Motility is % moving Morphology is % shaped and formed normally

44 Selecting Does for Reproduction
Polled Body condition Conformation Attachment of mammary gland Normal vulva Multiple births, growth Avoid birth defects

45 Sexual Behavior in Goats
Is both instinctive and learned Sexual behavior begins before sexual maturity (3 months of age) Sex drive is heritable and varies in the goat population These goats are young, penned and excited. They are practicing!

46 Signs of Heat in the Doe Seen best in sight and sound contact of a buck Standing to be mated! Seeking out the buck Vocalization Swollen vulva with mucous discharge Flagging and increased urination Standing to be mated is by far the best sign of heat

47 Breeding Systems for Does
Most are pasture bred The stocking rate varies but one buck per 20 to 100 does is most often recommended

48 Estrous Synchronization
Hormones can be used to have does come in heat at about the same time. Is used to shorten the kidding season, or when AI is used Works best if does are all cycling well 2 injections of prostaglandins given 10 days apart Progesterone as an implant or vaginal implant No product is cleared by the FDA for goats Details of programs vary and goats respond variably according to breed and other factors.

49 Artificial Insemination
Uses frozen semen Broader use of better or distant bucks Requires time, training, equipment and management Conception rates of to 75% have been reported with skilled inseminators Does are fairly easy to inseminate, but catching them in heat may be a problem Most does are bred in milking stands rather than flipped over like this one.

50 Embryo Transfer Increases the reproductive rate for does but at a cost
3 pregnancies per procedure Successful embryo transfer requires specialized training and lots of experience

51 Steps in Embryo Transfer
Donor selection Recipient selection Estrous synchronization of donor and recipients Superovulation of donor Breeding donor Embryo recovery Putting embryoes in recipients Objective measures of what make a superior female are hard to come by in the goat world Recipients should be healthy, fertile females rather than culls Recipients must be in heat at about the same time as donors for pregnancy to occur Collecting several embryoes per procedure brings down the cost per pregnancy

52 Pregnancy Diagnosis in Does
Wait for kidding (150 days-100%) Blood or milk progesterone (19 to 24 days-90%) Blood or urine estrone sulfate (50 to 60 days-near 100%) Radiography (after 70 days-near 100%) Ultrasound (after 35 days-90%+) The range or earliest date the technique is useful and its estimated accuracy is listed in parentheses.

53 Pregnancy Facts Average length is 150 days Restlessness for 12 hours
Labor for 2 hours or less Afterbirth falls away at an average of 6 hours 95% of kiddings do not require help Examine does after 1 hour of labor

54 Caring for newborn kids
Let the does do it if she will! Dry kids off Rub the chest to stimulate breathing Dip the navel with iodine Give colostrum if in doubt Let the doe do her job and bond with the kid if at all possible.

55 Pseudopregnancy in Does
The doe acts and looks pregnant but is not 3-5% of dairy does on some farms More likely with late fall pregnancies They “deliver” a large amount of clear fluid and may repeat in later years. Consider culling The animals health is not affected. Some hormone measurements will inaccurately call affected animals pregnant.

56 Cystic Ovarian Disease
2% of does affected Affected does show heat every few days but do not become pregnant Does may be treated but culling is a good idea Treatment with hormones may help but affected does tend to have the problem again. Female offpring of affected does are thought to be more likely to have this problem.

57 Abortion in Does Expelling a fetus before it can live
Up to 5% of healthy does may abort Diagnosis requires a diagnostic lab Toxoplasma, Chlamydia and other causes have been diagnosed The cause of abortion can not be determined by just looking at aborted goat fetuses or aborting does.

58 Intersex Condition in Goats
Associated with being polled and dairy breeds Animals are genetic females but have a mixture of reproductive organs They are sterile and should be culled This is what appears to be testicles on either side of a small, malformed vulva

59 THE END Questions?

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