| Swine Theriogenology | ||
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Phillip G. Hoyt, DVM
Course # 5326 Fall 1998 References: American College of Theriogenologists and Society for Theriogenology and American Association of Swine Practitioners. Proceedings of Swine Reproduction Symposium, August, 1996. Kirkwood, R.N.; Thacker, P.A.: Increasing Reproductive Performance. Large Animal Veterinarian, pp. 26-32, September / October 1988 Kirkwood, R.N.; Thacker, P.A.: Gilt Management Tips. Hog Farm Management, pp. 25-28, May 1988 Almond, G.W.; Dial, G.D.: Pregnancy Diagnosis in Swine: Principles, Applications, and Accuracy of Available Techniques. JAVMA, 191(7):858-870, Oct. 1, 1987 McDonald, L. E.: Veterinary Endocrinology and Reproduction, 1971 Pond, W. G.; Houpt, K. A.: The Biology of the Pig Pond, W. G.; Maner, J. H.: Swine Production in Temperate and Tropical Environments Wrathall, A. E.: Prenatal Survival in Pigs: Part I Wrathall, A. E.: Reproductive Disorders in Pigs Marrow, D.A.: Current Therapy in Theriogenology Reproductive Examination of the Boar. Journal of the Society for Theriogenology, Volume XIII In a 1981 Swedish study done by Ehnval et al on 2041 replacement gilts the reasons for culling were listed. Reason for Number of Percentage of Culled in percent culling culled gilts culled gilts of recruited gilts Slow growth rate 162 14.6 7.9 High backfat thickness 308 27.7 15.1 High backfat thickness and inverted teats 76 6.8 3.7 Inverted teats 130 11.7 6.4 Anestrus 122 11.0 6.0 Repeat breeding 34 3.1 1.7 Not Pregnant 73 6.6 3.6 Abortion 11 1.0 .5 Miscellaneous 196 17.6 9.6 Total 1112 100.1 54.5 54.5% of the recruited gilts were culled. 21.7% of the culls were due to reproductive problems. Up until 9 months of age, the majority were culled because of slow growth rate, high backfat thickness, and inverted teats. After 9 months of age 66.9% of the culls were because of reproductive failure. 34% of these because of anestrus. Delayed puberty was the dominating reason. 6% of all gilts were culled because of anestrus. Predictable gilt breeding activity 12 strong normal pigs 100% survival to weaning Prompt conception after weaning Litters and pigs per sow per year: 114 day gestation 21 day lactation 5 day rebreeding 365 = 2.6 litters per year 140 day farrowing interval 140 Pigs weaned per litter = 12 2.6 X 12 = 31.2 pigs weaned per sow per year Main reasons for poor reproductive performance: Late puberty Boar locomotor, behavioral , and infertility problems Low conception rates Pregnancy loss from abortions and pseudopregnancy Seasonal infertility High culling rate among sows and boars Small litter size Undetected nonpregnant sows Preweaning loss Perinatal (shortly after birth) loss Records needed to evaluate the performance: Matings per week Monthly breeding herd inventory Boar usage charts Litters per sow per year Litter size Pigs weaned per litter Percentage of females in heat 7 days postweaning Slaughter checks of culled breeding stock: Cycling animals (CL and/or large follicles) Inactive ovaries (no CL and small follicles) Double mating a sow at 12-24 hour intervals: Increases conception rates Using different boars masks a boar with low fertility 1-2 extra pigs per litter Pen mating: 1 boar or more in a group of sows for 23-45 days 1 boar per 8-10 sows for continuous farrowing Rotate boars every 8-24 hours for double mating benefits Disadvantages: Can't identify bred females Can't observe mating behavior Can't identify the sire of the offspring In large groups, some sows may not get bred Mask boars with poor libido or depressed mating ability Pasture breeding: Very similar to pen mating Being replaced because of confinement Hand mating: Estrus sows taken to breeding pen Advantages: Disadvantages: Close observation of mating behavior Good heat detection (Essential) Accurate breeding dates May require a vasectomized boar Controlled multiple matings Labor intensive Control of boar usage Artificial insemination: Advantages: Disadvantages: Few boars needed Similar to hand mating Use of higher quality boars Very labor intensive Equipment needs Number of boars needed depends on: Age of boars Mating system Libido Lameness incidence Breeding pen size Season of the year Weaning practices Initiate puberty in gilts and heat detection Each pregnant uterine horn one meter or more in length Very tortuous Cervix: Muscular External orifice small with overlapping folds Spiral tip of penis penetrates 1-2 rings Ovaries: Many corpus luteum formed Both function at same time Left ovary ovulates 55-60% of ova Uterotubular junction: Not clearly defined Not a true sphincter Mucosal folds swell at the end of estrus Epithelial-chorial placentation: Six layers separate maternal and fetal blood Endothelium - Connective Tissue - Epithelium - Chorian - Connective Tissue - Endothelium Diffuse attachment Landrace earlier than Yorkshire Durocs are the latest Crossbreeds reach puberty earlier Delay puberty: Inbreeding Nutrition: Severely limiting feed intake Normal limit feeding doesn't delay puberty Vitamin B12 deficiency Protein deficiency Full feeding Excessively fat gilts Season of the year Confinement: Decreases number of gilts reaching puberty by 8-9 months 40-50% Increases age of puberty by 30-60 days Lighting (total darkness) Hasten puberty: Large breeds and crossbreeds Presence of boar: Gilts cycle up to 40 days sooner When the gilt reaches 170-190 days of age House gilts in groups Transport stress: Hauling Changing pens Mixing with new penmates Lighting: 18 hours of light and 6 hours of darkness ideal Intensity (10 - 20 candles is ideal) Average length of 21 days (19-23): Breed differences High environmental temperature has no effect on length Silent heats occasionally occur Proestrus: 1-3 days Alert to boar's approach, but will not let boar mount Mounts other sows & accepts mounting by other sows Estrus: 3-4 days but sow mates for only 2-3 days Red swollen vulva and vaginal discharge Extreme restlessness and spontaneous activity (fence walking, follow moving objects) Mounts other animals & frequent mounting by other sows Frequent urination Will seek out boar Mating stance (immobility reaction) All 4 legs locked in extension Ears cocked Stimulated by: Pressure on back or rump Olfactory (boar pheromones) Auditory (boar sounds) Visual and tactile stimuli lessor role Metestrus: 2 days Very similar to diestrus Diestrus: 14 days Boar fiercely rejected Poor success with the vaginal smear in detecting cycle stage Corpus luteum fully developed 7 days after start of estrus CL progesterone decreases 14 days after estrus starts CL regression starts 15 days after estrus starts Reproductive life of many years Ovulation: Occurs spontaneously from mid to late estrus: Last 1/3 of estrus (36-40 hours after estrus onset) Breed differences Duration usually about 2 hours (extends to 6-8 hrs.) Ovulation rate: Mature sows between 15-20 (17) ova Gilts between 10-15 (13) ova Breed differences 40-50% heritability Increase ovulation rate: Flushing gilts 2 weeks prebreeding (questionable in sows) Older gilts: 10 days older equal .5 CL more Puberty through first 4-5 estrus cycles 1 - 2 more pigs / litter when bred on the 2 - 3 heat Heavier gilts at weaning and breeding Decrease ovulation rate: High environmental temperature Age of sow (fewer ova in gilts) Fertilization: Considered an all or none response (Several billion sperm and fewer than 24 ova) Percent fertilization after mating and ovulation: 24% after 2-3 hours 72% after 5 hours 100% after 8-14 hours Ova fertile for 24 hours after ovulation Breed during first half of estrus: 10-25.5 hours after start of estrus is optimal Second AI from 36-38 hours after standing heat starts 12 hours after onset is best for sows Sperm transport: Uterotubular junction in 10 minutes Number of sperm in oviduct not affected by live or dead sperm Sperm motility drastically reduced after 2 hours Sperm viable for 25-30 hours in oviduct Lower fertilization rates with older sperm Decreased embryonic survival with older sperm Conception rate: Percent of matings which result in viable fetuses First service conception rates in gilts and sows: 70% acceptable 90% possible Conception failure: Abnormal anatomy Boar infertility Cystic follicles Environmental temperature Improper timing Diseases Bacterial infection of reproductive tract or semen Double mating Heat stress reduces reproductive efficiency Embryonic & fetal mortality: 30-40% fetal mortality between 1 and 114 day of gestation Failure of fertilization is only 5-10% of prenatal loss 50% or more of losses during the first 25 days of gestation Embryonic survival influences litter size more than ovulation rate Intrauterine migration: Migrate for up to 12 days Must be at implantation site by day 13 Embryos in each horn from 10 to 12 days (after 12 days not needed) Day 12: Need at least 4 embryos Less than 4 embryos causes sow to recycle in 25-27 days Day 30: 2 live embryos needed to maintain pregnancy Increased embryonic death: High plane of nutrition immediately after breeding Large litters from excess progesterone from number of CL Starvation of gilts beyond 41 days without exogenous progesterone and estradiol High environmental temperature (summer infertility) Uterus: Limits embryos that survive the first month of gestation (mechanism is unknown) After 30 days space may be a problem (exceed 14 embryos) Mummies: Considerable loss Fetal death after 40 days More prevalent in large litters Stillborn: Increase during last 1/3 of farrowing Increase in large litters Pregnancy detection: Failure to show estrus 21 days after breeding Ultrasound at 30-90 days of gestation (film SVM library) Rectal palpation (difficult on gilts) Complete list: Almond, G.W.; Dial, G.D.: Pregnancy Diagnosis in Swine: Principles, Applications, and Accuracy of Available Techniques. JAVMA Oct. 1, 1987; 191(7):858-870. Gestation: Average of 114 days (3 months, 3 weeks, 3 days) Domestic pigs 10 days shorter than feral pigs Litter size: Depends on: Number of ova produced Percent fertilization Degree of prenatal mortality: Number of stillborn Number of mummies Number of embryonic death Maximum during 4-7 litter Gilts farrow an average of 1-2 pigs less: Second and subsequent litters larger with bigger pigs 1 - 2 more pigs / litter if gilts bred on 2 - 3 heat 60-70% of ova ovulated Small litters associated with a marginally fertile boar Breed differences Frozen semen decreases number of live pigs Induction of parturition: Why? Avoid weekend and holiday farrowing Equalize litter and pig sizes Better crate utilization Uniform post weaning estrus How? Prostaglandins: 10 mg at 112 days & 60-90% farrow in 18-36 hours (28 hrs) Before 112 days = small pigs and low survival After 112 days = less synchronization Give at 8:00 AM and sows farrow next day Oxytocin (doesn't always work) Corticosteroids (decreases neonatal survival) Parturition (Farrowing): Behavioral changes: Uneasy Nest Colostrum Fetal adrenal glands important in onset Duration from 1-2 hours to 24 hours (4 +/- 30 minutes) Rules of thumb: 2 hours for first pig Pig every 1/2-1 hour (19 min.) Examine sow if times are longer Placentas passed when finished One or more pigs before any placenta Head or rear feet first are normal presentations (65% head first) Umbilical cord still attached at birth (pig breaks after birth) Obstetrical care: (Minimal usually) Manual: Lubrication Gentle C-section: Good sow survival if labor less than 6 hours Decline in sow survival with longer labor Artificial respiration: Clean mucus from pig's nose Make loose fist with hand Pig's nose pushed up behind thumb and trigger finger Blow through thumb and trigger finger Lactation: Select replacements with 7 functional teats per side: 3 per side anterior to the umbilicus No ovulation Signs of heat may occur 1-3 days after farrowing (no ovulation) Estrus and ovulation 3-14 days (5-10 days) after weaning: 8 week weaning = 5-7 days return to estrus Shorter weaning = longer return to estrus 2 day weaning = 14 day return to estrus Induce estrus by temporary removal of pigs (1 day) Estrus synchronization by weaning Milk supplementation: Pig physiology: Average duration on milk letdown is 28 seconds Nurse every 65 minutes 32 hours to establish teat order Recognize mother by three days Commercial milk replacers available: Cow colostrum: (Not good, but helps) Freeze in ice cube trays 1 cube per pig every 1-2 hours Control of the estrus cycle: Weaning and heat in 5 - 14 days (Most common) Prostaglandin: 5 mg per sow Given on day 12-13 Luteolytic PMS (400 IU) at weaning: HCG (LH) (200 IU) or GnRH 96 hours later Ovulation in 2 days PMS (1200 IU) in cycling sows: HCG (500-1000 IU) 96 hours later Ovulation Oral estrogens followed by progesterone in cycling sows Oral dithiocarbanoylhydrazine derivative for 18-20 days: PMS on day after drug removal HCG 96 hours later Gilts ovulate about 40 hours later Low fertility (poor conception and small litters) with induced estrus: Gilts should be bred at the following estrus Many gilts fail to show a second estrus Work in sows Product available since March, 1990. "P.G. 600" (400 I.U. PMSG and 200 I.U. HCG) IM Fertile estrus in 3 - 10 days in 59% gilts which are non-cycling, 5 1/2 months old, and weighing >185 pounds Will not work on cycling gilts or those under 5 1/2 months old or <185 # Altrenogest ("Regumate"): 15-20 mg per day 18 days Heat in 3-5 days Embryo transfer: Has been done Superovulation by exogenous gonadotrophins (PMSG) Surgical procedure Fertilized ova transferred: 2-8 cell stage Ova collected 5-6 days after mating are best Blastocysts recovered on day 7-8 have produced pregnancy Donors 1-2 days before or 1 day later than recipients Anestrus: Failure to show heat or failure of heat detection: Sow Boar People Delayed puberty: Infantile reproductive tracts Confinement Season Other Pregnancy Lactation Seasonal anestrus: July, August, and September in the U.S.A. More infantile reproductive tracts in the late summer More postweaning anestrus Especially in first litter gilts and old sows Sudden elevation of ambient temperatures Negative nutritional balance Pseudopregnancy: All fetuses reabsorbed Hormonal pregnancy Mammary development and maternal behavior Prevalence and cause is not understood Silent estrus: Behavioral anestrus Up to 30% of confinement gilts Hormonal events occur Estrus behavior doesn't occur Presence of an active CL Nonfunctional ovaries: Confinement gilts 1-2 normal cycles and then anestrus No infectious agents cause anestrus: Clinical ill or debilitated animal not likely to cycle Systemic disease Chronic infections of the uterus and oviducts Cystic ovarian degeneration (not common) Poor boar libido: Not anestrus Owners call it anestrus Management failure: Missed estrus Can't recognize estrus Poor design of breeding area Poor facilities making it difficult to move and observe animals Return to estrus: Regular: Prior to 25 days post mating Failure to conceive Embryonic death before day 12 Irregular (delayed): After 25 days post mating Pregnancy failure after day 12 Undetected because estrus detections stop after 40 days Increase during July, August, and September Infectious agents (parvovirus, brucellosis, etc.) Pregnancy loss: Abortion Difference between number farrowed and number bred or diagnosed pregnant 5-10% loss is accepted on most farms: With ultrasound pregnancy diagnosis before 40 days May reach 20% in the summer and fall Abortions: Causes: Maternal failure: Systemic reaction (toxemia) Febrile reaction (acute erysipelas, acute salmonellosis) Endometritis Few or no pathologic changes in fetus Conceptus failure Combination of both Survey: 22% viral causes: 16.5% bacterial and fungal causes (leptospirosis mainly) 61.5% undiagnosed Seasonal pattern (late summer period of low fertility) High carbon monoxide levels Reproductive tract infections cause sporadic abortions: Actinomyces (Corynebacterium) pyogenes Pasteurella multocida Staphylococcus aureus Streptococcus Brucella suis: Any stage of gestation Occurs 30 days post exposure Few signs in early abortions, just a return to estrus Purulent vaginal discharge in later abortions Leptospira: Well developed placenta required (after the second month) Occurs 2-4 weeks after exposure Diseased or dead pigs Abortion storms Pseudorabies and swine fever (viremia) Mycotoxicosis Environmental stress, fighting, and heat stress Stillborns: 5-7% of all pigs farrowed Umbilical cord: 24-30 inches long (uterus 5-6 feet long) After cord ruptures, the pig must be born in 5 minutes Very low anoxic tolerance (hypoxia results in weak pigs) Meconium in lungs and trachea and on the skin Two types: Type 1 die before parturition (can be infectious agents) Type 2 die during parturition (usually noninfectious) Infectious agents: Brucella suis Parvovirus Leptospira Enterovirus Swine fever Pseudorabies Estrogenic mycotoxicosis Environmental factors: Heat stress: (Temperature of 39 C or higher on days 102-110) Increases number of stillborns Decreases number of pigs Decreases birth weights Nutritional deficiencies Infectious agents High levels of carbon monoxide: Gas heaters Ventilation Hemoglobin levels below 9 g/100 ml in sows: Iron deficiency Eperythrozoonosis Congenital abnormalities Duration of farrowing: 1 hour = 2.4% stillborn 8 hours = 10.5% stillborn Increase when 45-55 minutes between pigs Increase in the last 1/3 of the litter Litter size: Increase in litters of <4 or >9 Mummies: Death of fetus after 34 days of gestation (skeletal calcification) Brown, dry, shriveled up fetus (leather) Disintegration of fetus results in macerated fetus Prolonged gestation length: No fetal adrenals Weeks passed due Most commonly follows viral infections: Parvovirus (most common) Enteroviruses Swine fever Pseudorabies Leptospirosis Toxoplasma gondii (protozoan) Malformations: Often born alive Survival depends on the severity Occur between 14-25 days of gestation Inherited congenital disorders: Atresia ani Cranioschisis Splayleg (questionable) Lumbar spinal defects Various limb abnormalities Cleft palate Hydrocephalus Nutritional deficiencies: Vitamin A Calcium Panothenic acid Iodine Teratogenic agents (limb abnormalities): Tobacco plant (Nicotiana tabacum) Jimson weed (Datura stramonium) Hemlock (Conium maculatum) Hormone-like substance: Methallibure: Estrus synchronization of gilts Malformed pigs if feed to pregnant sows Viral infections: Death or malformation depending on organ involvement Type of malformation depends on which tissue involved Low conception rates or repeat breeding: 80-85% farrowing rate in sows mated at first post weaning estrus Fertilization failure or very early embryonic death Low conception rates and small litters caused by boar and/or sow: Boar: Sperm defects Toxins (estrogenic mycotoxins) Heat stress (2 months) Musculoskeletal problems Severe febrile condition Orchitis (Brucella suis) Sow or gilt: Anatomical abnormalities Viral diseases Cystic ovarian disease Adhesions on oviduct or bursa Metritis and endometritis Return to estrus after 24 days: Embryonic death 12 days or later after fertilization Endocrine disturbances (ovarian cysts) Nutrition: Energy: Deficiency: Long post-weaning estrus interval Few problems unless severe restriction post mating If pig birth weight doesn't drop below 1 kg, no effect on survival Excessive: Increases early embryonic death Fat sows Protein deficiency: Increases weaning to estrus interval esp. in gilts Maintain pregnancy but a 20-25% decrease in birth weight 15% protein lactation ration sufficient for reproduction Ration quality and quantity after weaning affects ability to return to estrus and conceive: High nutrition post weaning reduces interval and variability of return to estrus (esp. gilts) High levels to sows post weaning (higher percentages show heatin 7 days) No severe effect on boars: Deficiencies can alter his health and well being Don't want a fat boar Reproductive abnormalities: Extreme muscling: Delayed puberty Poor mothering ability Low conception rate Pick gilts for soundness and reproduction Farrowing difficulty Infantile vulva: Rosebud vulva Accompanied by infantile uterine horns and nonfunctional ovaries Seen more in confinement gilts (higher in tethered gilts) Seen more in heavily muscled gilts Some can be stimulated to develop by transport and boar exposure PMSG helps some gilts Should you treat? Tipped vulva: Sky-hooked vulva Erectile tissue in vulva Effect on future reproduction is unknown May indicate other reproductive abnormalities Boars have difficulty breeding these gilts Shouldn't be kept for breeding stock Vulva injuries: Fighting Parturition Usually no effect on reproduction Atresia ani: Imperforate anus Females have a rectovaginal fistula anterior to the vulva Males die in 1-4 weeks Two pair of dominant genes or viral infections Red swollen vulvas: Appear like a sow in heat Mammary development Exogenous estrogenic substances Faulty underline (teats): Blind teats, pin teats, and inverted nipples Lack of sufficient teats: 7 per side Abrasive concrete can cause underline problems Poor teat spacing 3 teats on each side anterior to umbilicus Evenly spaced Straight line Replacement selection Reproductive tract deformities: 5-10% of all gilts have abnormal reproductive tracts Slaughter checks are required for diagnosing the problems: Hydrosalpinx or pyosalpinx: Clear fluid or purulent material in oviducts Occlusion or distention of oviducts Abnormal embryonic development Hereditary Irregular or absence of estrus Blind uterine horn: Unilateral Normal cycle Can get pregnant in unaffected horn but small litter results Pregnancy depends on the size of the blind horn Unilateral missing horn: Infrequent Normal cycle Small litter Blind, double, or missing cervix: Infrequent Normal cycle Blind or missing cervix can't get pregnant Double cervix can get pregnant Infantilism: Common Seen more in confinement gilts Ass. with rosebud vulva Absence of estrus 30% of the size of a normal cycling reproductive tract Hypoplastic nonfunctional ovaries Adhesions: Whole tract can be affected (oviduct and bursa most common) Intraperitoneal injections?? Signs depend on the severity Intersexuality (hermaphrodites): .5% of the total population More prevalent in Yorkshire (genetic?) Genetic females usually: True hermaphrodite Autosomal recessive Ovarian and testicular tissue separately or together (internal or external) Male pseudohermaphrodite: Phenotype female External and internal female Testes instead of ovaries Male behavior Study pedigree to remove carriers Cystic ovaries: Large cystic follicles or corpora luteum Irregular cycling (longer heat periods than normal) Enlarged clitoris in some sows Mainly secrete progesterone Partial or complete failure of ovulation Mycotoxins or exogenous steroids Diagnosis difficult on live animal Slaughter checks Treatment usually ineffective Diagnosis: Physical exam Herd history Breeding records Slaughter checks Treatment: Limited usefulness Good!! Select better females Don't create more problems Locomotor causes of reproductive failure: High culling rate High preweaning mortality Leg weakness: Cause unknown Combination: Rapid growth rate, good feed efficiency, and restricted exercise Conformation (abnormal angulation of joints) Osteochondrosis Foot rot: Flooring Abrasions and cracked hoof walls Osteomalacia: Downer sow in mid to late lactation Fractures of the femur or vertebra If they can't walk, they can't breed and reproduce. SMEDI Not a disease Group of clinical signs S = Stillborn M = Mummies ED = Embryonic Death I = Infertility Syndrome I: Fatal infection of embryo or fetus Dam is clinically normal (subclinical infection) Abortion rare Resorption of embryo or mummification of fetus Earlier in gestation, fetus more susceptible Porcine parvovirus, porcine enterovirus, Japanese B encephalitis virus Occasionally hog cholera virus and pseudorabies virus Problem not recognized until long after fetal death Except for parvovirus, viruses inactivated by mummification Syndrome II: Maternal illness with or without disease of fetus Abortion especially if in late gestation Pseudorabies, hog cholera, and swine influenza Viruses isolated from aborted fetus and newborn Porcine Parvovirus Nearly 100% morbidity in older breeding stock Worldwide distribution Extremely resistant virus Can be transmitted by copulation Boar fertility not affected Transplacental infection during first half of gestation Sow (No clinical signs) Fetus immunocompetent in the last half of gestation Virus isolated from mummies (FA of fetal tissue best) Vaccine available Porcine Enterovirus 9 serotypes Worldwide distribution Can be transmitted by copulation Subclinical in sow and decreased semen quality Developmental abnormalities reported (not common) Isolated from tissues of affected pigs No vaccination Japanese B Encephalitis Virus Not in U.S.A. Asia primarily Mosquito transmission No effect on boar Not transmitted by copulation Developmental abnormalities common (hydrocephalus) Affects fetus late in gestation: Stillborn Weak live pigs with nonsuppurative encephalitis Virus isolation and culture for diagnosis Vaccination, vector control, and controlled breeding Pseudorabies Virus Worldwide distribution Severe maternal disease Subclinical maternal and death to fetus Virus isolation from sow, fetus, or stillborn Vaccination and isolation of susceptible animals Swine Influenza Virus Prevalent in U.S.A. 20% of swine have antibodies Disruption of fetal nutrition during maternal respiratory disease Virus isolation from sow and fetus Vaccine available Hog Cholera Virus Worldwide U.S.A. is free!! Abortion Embryonic resorption, mummies, fetal abnormalities, stillborn, and weak pigs FA for diagnosis Porcine Reproductive and Respiratory Syndrome Lelystad virus (family Togaviridae) Affects pregnant females, unweaned and recently weaned pigs, and growing and finishing pigs Stillborn, abortion, mummies, autolyzed fetuses, and small litters Interstitial pneumonia and bronchopneumonia FA on fresh lung tissue and virus isolation for diagnosis Vaccines available (MLV or killed) Leptospirosis Primarily a reproductive disease in swine Mild signs in adults Serotypes: L. canicola L. grippotyphosa L. icterohaemorrhagiae L. pomona L. bratislava Shed primarily in urine Venereal transmission possible but not common Contaminated surface water the common source of infection Abortion occurs 1-3 weeks after fetal infection Infections late in gestation cause stillborn and weak pigs Mummification Vaccination and decrease surface water contact Brucellosis Orchitis and epididymitis in boars Embryonic death and abortion Can affect locomotor system (posterior paralysis) Stillborn or weak pigs Infertility No treatment Depopulation Validated free herd Vaginal prolapse: Replace Purse string suture Urinary catheter Cull Rectal prolapse: Replace and purse string suture Submucosal resection and purse string suture Rectal rings Amputation Cull Uterine prolapse: Some can be replaced vaginally (Very few) Abdominal incision and pull uterus back into abdomen Amputation Emergency slaughter Hematoma of vulva: Do nothing on a small hematoma If it ruptures, ligate arteries Horizontal mattress suture at the base of the vulva Lateroflexion of the bladder: Older gravid sow usually Bladder reflects between pelvis and vaginal wall Catheterize the bladder Use Foley balloon catheter and tape it in place C-section: Prognosis depends on how long sow has been in labor (over 6 hrs decreased prognosis) Either flank, ventral midline, or lateral & parallel to mammary gland approaches. Routine surgical procedure. Typical reproductive organs and accessory glands: Testicles Seminal vesicles Epididymis Cowper's gland (bulbourethral gland) Vas deferens Prostate Tip of penis with a left corkscrew twist Semen: Presperm fraction: High bacterial contamination Secretions of accessory sex glands Very few sperm Sperm rich fraction: Largest concentration of sperm Largest volume Postsperm fraction: Mainly gelatinous material Few sperm Strained out for AI use Semen volume and concentration: 250 ml (150-500) 100 million sperm per milliliter (25-300) Depends on size, age, and frequency of usage To increase semen production, house boars separately Daily collection gives more total semen and sperm production Semen volume: Testes and epididymis 2.5% of total Prostate and urethral glands 55-75% of total Seminal vesicles 15-20% of total Bulbourethral gland 10-25% of total Removal of accessory gland has no effect on other glands, ejaculation or libido Removal of seminal vesicles and bulbourethral gland No effect on fertility Decrease the number of abnormal sperm Increase the duration of sperm motility Puberty: Gradual process beginning at 4 months of age 6-8 months Feed restriction: Decreases growth rate Delays puberty Mature: Size at 1 year old Kept until 5-6 years of age Culled for reasons other than fertility: Bad attitude Lameness Size Etc. Number of boars required: Pen breeding 1 boar per 8-10 sows for continuous farrowing 1 boar per 5 sows for all in - all out farrowing 6 1/2 months of age 1-2 services per week 8-10 months of age 5 services per week 10-12 months of age 2 services per day 8 services per week Mature boar 3 services per day 12 services per week Castrated boar = barrow Temperature: High temperature can result in 2 month infertility Cold temperatures do not decrease reproductive function Depends on the behavioral reactions of sow If it stands still, breed it Must chase, sniff and nudge every sow in pen Pheromones: Preputial washings and submaxillary salivary glands Important for successful stimulation of sow Aerosol spray commercially available Reduces weaning to estrus interval Makes boar meat smell Courting song: Chant de cour Stimulates sow 3-20 minute ejaculation time Severe fighting among unfamiliar boars: (death and/or injury) Dominant boar breeds most often Shy breeders may need sow brought to them Boars raised in all male groups form stable homosexual pairs Semen storage and AI: AI not used extensively in U.S.A. Problems with AI: Heat detection Poor survival of fresh sperm beyond 3 days (viability 4-5 days) Semen storage: At 5-8 C for 30 hours doesn't affect fertility Looses motility and settles out on short-term storage Reactivated by warming and shaking at 37 degree C Artificial insemination: 50 ml total semen volume 3 billion sperm needed Assuming 60% motility, 5 billion sperm in 50 ml fluid Diluents (extenders): None promote sperm viability beyond a few days Sodium sulfate and potassium sulfate Calcium chloride and peptone Egg yolk-phosphate mixture Glucose tartrate and tartonic acid Milk and cream Citrate and phosphate extenders used for bull semen is toxic to boar sperm Freezing: Causes loss of motility and fertility Techniques have been developed Fertile boar: Normal libido Ability to mount sow Ability to protrude penis and penetrate vagina and cervix Ability to fertilize ova History: Age Origin Vaccinations Serological tests: Brucellosis Pseudorabies Previous diseases How long on current premises: Time in isolation (30 days minimum) Exposure to prospective breeding herd (30 days minimum) Frequency of use: Time of last usage Number of services per week Conformation and body condition Locomotor function: Ability to move Ease of movement Front and rear legs Stifles, shoulders, knees, hocks, fetlocks, and pasterns Top line (back) Feet!! Size of tusks Libido: Inexperience Overwork High ambient temperature Ability to mate Genital exam: All external parts present and accounted for Testes: Symmetrical Resilient Large (10-15 cm long and 6-7 cm wide in mature boar) Functional penis: Injuries Incomplete erection Hypospadias (urethra opens ventrally) Persistent frenulum Balling of penis in preputial diverticulum Semen evaluation Best: Libido Ability to mount and enter vagina Sow in estrus Glove on hand Boar mounts sow Gently grasp penis Ejaculate collected in a prewarmed thermos (37 C) covered with a layer of coarse gauze to filter out gel fraction Artificial vagina: Not practical because of equipment, sanitization, and cost No improvement over gloved hand method Electroejaculation: Primarily sperm-rich fraction collected Used in specialized cases: Lame or injured boar No sow in heat Old boar Shy boar Bad attitude Restraint: No anesthesia: (injury to boar and/or handlers) Anesthesia: Ultra-short-acting barbiturates: Surital at 4.4 mg/kg for first 180 kg then 2.4 mg/kg 8 mg/kg maximum dose 1 gram/ 350 pounds (140 kg) Light plane of anesthesia Halothane: Face mask Porcine stress syndrome Xylazine (1 mg/#) plus ketamine (1 mg/#) IV Procedure: Remove feces from rectum Lubrication Insert probe approximately 25 cm into rectum Express preputial diverticulum Clip hairs around prepuce Manual exposure of penis: Light electrical stimulation Push sheath caudally Grasp glans penis Atraumatic forceps to grasp the tip of penis: Bozeman uterine dressing forceps Rubber padded sponge forceps Simulate for 5-7 seconds and rest for 5-10 seconds Semen collected in prewarmed container Advantages: Collection from boars unable or unwilling to mate Convenience Testicles and penis easily examined Disadvantages: Libido and mating ability not examined Possible anesthetic accidents Small volume Age of Boar 8 - 12 over 12 Interference months months Levels Volume 100-300 ml 100-500ml Color opalescent to milky watery to pink Concentration 50-200 250-500 <50 (sperm / ml) X 106 X 106 X 106 Total sperm 15-30 30-50 <15 X 109 X 109 X 109 Motility >85% >85% <60 Wave motion (0-4) 2-3 2-3 Progressive motility >70% >70% Primary abnormalities <10% <15% abnormal heads <5% <5% >10% proximal droplets <10% <10% >20% abnormal acrosomes <5% <5% >10% abnormal midpieces <5% <5% >10% Secondary abnormalities <10% <15% detached heads <5% <5% >10% Normal sperm >85% >85% <75% Free of blood, pus, and foreign material + + Equipment control: 37 degree C temperature No pH change No disinfectants No sunlight Clean, dry, and warm Check motility as soon as possible: Wave motion rated 0-4: 0 = absence of wave motion 1 = absence of wave motion but individual sperm motility 2-3 in normal fertile boars Progressive motility: Dilute with isotonic saline or buffered 2.9% sodium citrate Cover with a coverslip Evaluate for linear motility Volume: Only the gel-free volume measured (Varies according to collection method) Concentration: Color RBC unipettes (1:200 dilution) and a hemocytometer Coulter counter Spectrophotometer Total sperm = sperm / ml X volume Morphology: Stained slides (5% nigrosin-eosin or new methylene blue) View 100 cells (200 is better) Normal Primary abnormalities All head and midpiece defects Double midpieces Small, enlarged, double, and misshapen heads Proximal droplets Acrosomal defects Double tails Enlarged midpieces Tightly curled tails Secondary abnormalities: Distal protoplasmic droplets and bent tails: May not be significant Don't appear to affect fertility Commonly observed in rested and older boars Detached heads Abaxial midpiece attachments considered normal in the boar Occasionally normal appearing semen may not cause conception: Be careful Young boars (20-50% unacceptable breeders the first year) Infertile boar = sausage Very few sterile boars, many may be marginally fertile Usually treatment should not be recommended |
Swine
Index
