ADSC 2010 Lecture 27Outline of Last Lecture I. Reproduction- Gestation LengthII. Reproduction- ParturitionA. Preparatory StageB. Expulsion of FetusC. Expulsion of PlacentaIII. Factors Influencing Fetal Size1. Genetics2. Age and Size of Dam3. Nutrition4. Litter Size5. Ambient Temperature6. Fetal HormonesOutline of Current Lecture I. Reproduction: Post-Partum Estrus A. CattleB. EweC. SowD. MareII. Management of the Reproductive Tract III. Estrus in the FemaleIV. Estrus DetectionCurrent Lecture: I. Reproduction: Post-Partum Estrus A. Cattlea. Dairy: 30-70 daysb. Beef: 45-105 days- Suckling or increased frequency of milking will delay the first “estrus” after calving- Take calf away from cow for a day to stimulate estrus- Anestrus: not cycling- Estrus: time ovulating/receptiveB. Ewe- Seasonal breeders- Shorter days stimulate “estrus” : fall/winter- Considerable variation C. Sow- Anovulatory estrus 1-3 days: not ovulating- Don’t usually cycle during lactation- Wean pigs- functional ovulatory estruso 5-7 days post-weaning to first ovulatory “estrus”D. Mare- Seasonal breeders- Foal heat: 5-15 days after birth- Functional because long gestation period: ovulation- To maintain annual production: can breedo Requires more care- Longer days stimulates “estrus” – spring- May show signs all year- Seasonal breeding: target production of offspring before growth/flush of foodII. Management of the Reproductive Tract A. Estrus SynchronizationB. Artificial insemination (AI)- Utilize superior genetics, increases quality, cheaper rateC. Embryo Transfer- Female produces large numbers of fertilized embryos** put into another femaleD. Pregnancy DetectionIII. Estrus in the FemaleA. Signs of Estrusa. Cowo Swelling redness of vulvao Restlessness/vocalizationo Rides herdmates: typical Bos cowo Stands to be mountedo Clear mucous dischargeb. Eweo Few signs except standing to be ridden by matec. Sowo Swelling redness of vulvao Restless/vocalizationo Mounting other sowso Stands to be mountedo Stands to hand pressure: pressure on back- responds accordingly ifin heato Erect earsd. Mareo Nervousnesso Frequent urination: squattingo Winking of vulvao Stands for maleIV. Estrus DetectionA. Cowo Visual observation (am / pm)o Marker animal (chin ball marker)o Female - Androgen treatedo Male - vasectomized, penectomized, penile deviatedo Heat detection patches - KMAR Patcho “Heat Watch” - electronic detection systemB. Eweo Vasectomized ram with breast marker / marking harnessC. Sowo Boar exposure / hand pressureD. Mareo “Teasing” with a stallion - note acceptance or rejection- not always safe: stallion can get aggressive Sometimes use pony/stud: easier to manage try to have some kind of separation If not in estrus: female may try to
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