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REPRODUCTION Reproduction is most important trait

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Presentation on theme: "REPRODUCTION Reproduction is most important trait"— Presentation transcript:


2 REPRODUCTION Reproduction is most important trait
Bull - represents > 50% of the herd No. of cows per bull ??? percent calf crop & conception rate Ave. age of herd- Generation Interval A. I. vs E. T. vs natural Body Condition Scores (1-9)

3 Reproduction of Cattle
functions of the cow produce eggs develop calf fetus give birth produce milk functions of the bull produce sperm, semen, and testosterone

4 Breeding and selection
Breeding habits months of age (Puberty) Age vs. size to breed mos. or at least 65 % of mature weight (breed dependent) Estrus / hours Estrous Cycle / day intervals Occurrence / 6-8 weeks after parturition

5 Breeding and selection
signs of estrus nervousness, attempts to mount others, swelling of vulva, frequent urination, mucous discharge breed the last 10 hours of standing heat or the first 10 hours after standing heat Twelve hours after observed in standing heat or hours after initial heat

6 MALE ANATOMY Testicles- primary sex organ
produces sperm cells (spermatogenesis) Seminiferous tubules- within the testicle place where sperm cells are formed Interstitial or Leydig cells Place where testosterone is produced Scrotum- regulates temperature of the testicles (tunical dartos muscle)

7 MALE ANATOMY Cryptorchidism- one or both testicle that do not descend into the scrotum during embryonic development Epididymis- four functions for sperm cells transport storage maturation concentration

8 MALE ANATOMY Ampullae – storage of sperm before ejaculation
Vas deferens - function is to transport spermatozoa to the urethra Secondary sex glands that produce seminal fluid – cowpers, seminal vesicles, and prostate

9 MALE ANATOMY Pampiniform plexus- network of arteries and veins to provide blood supply of the testicles located above the testicle within the spermatic cord Penis and urethra- transport spermatozoa to the female for natural insemination

10 HORMONAL CONTROL MALE Influenced by the anterior lobe of the pituitary gland Gonadotrophic hormones that affect the male FSH (follicle stimulating hormone) development of seminiferous tubules and sperm cells LH (luteinizing hormone) influences interstitual cells to secrete testosterone

11 SEMEN Criteria motility – minimum 70%
percentage of normal versus abnormal sperm cells Volume concentration

12 To produce the eggs or ova to be fertilized by sperm
Female Anatomy Functions To produce the eggs or ova to be fertilized by sperm To serve as as receptacle for the penis during copulation To house and nourish the fetus until parturition

13 Female Anatomy Ovaries Produce eggs Produce female hormones estrogen
progesterone stimulates the development of secondary sex organs and sexual receptivity maintains uterine lining during pregnancy keeps estrus from occurring causes mammary system to develop

14 Female Anatomy Ovaries Follicle
blister-like mass on the surface of an ovary containing a developing ovum (egg) follicle ovum

15 Female Anatomy Ovaries Follicle functions hold the growing ovum
secreted from follicle to signal the remainder of the reproductive tract to prepare for ovulation Follicle functions hold the growing ovum produce and store estrogen at ovulation, the follicle ruptures, expels the ovum, enters the infundibulum and awaits fertilization in the oviduct

16 Female Anatomy Ovaries Corpus Luteum (CL)
forms after ovum is released from the follicle function produce progesterone

17 process of discharging an ovum from the mature follicle of an ovary
Female Anatomy Oviducts Transport eggs from ovary to uterus Are site of fertilization Infundibulums Pick eggs at ovulation and direct them into the body of the oviducts process of discharging an ovum from the mature follicle of an ovary

18 A sow has a very long uterus and a mare has a very short uterus
Female Anatomy Uterus Consists of horns and a body uterine horns uterine body Is site of embryonic growth Is site of placental and fetal development Varies in shape among species A sow has a very long uterus and a mare has a very short uterus

19 major barrier and protection of the uterus and developing fetus
Female Anatomy Vagina Is receptacle for the penis during copulation Serves as birth canal at parturition Is separated from uterus by the cervix Is passageway for expelling liquid wastes major barrier and protection of the uterus and developing fetus

20 Female Anatomy Vulva Clitoris
Is external portion of the female reproductive tract Serves to: protect internal system from infection initially receive the penis at copulation act as passageway for urine Clitoris Sensory erectile organ

21 HORMONAL CONTROL FEMALE Estradiol: produced by the Graafian follicle
Estrogen: a collective term for a number of hormones similar to estradiol Functions: development of secondary sex organs onset of estrus (heat cycle) affects rate and type of growth as well as deposition of fat

suppresses production of follicles and estrogen prepares the uterus to receive the fertilized egg

FSH- stimulates growth of the follicle LH- causes rupture of the follicle LTH (lactogenic hormone)- milk secretion Luteotropic hormone- formation and maintenance of the corpus luteum (CL)

24 Estrous Cycle University of Nebraska-Lincoln Learning Module


26 Estrus Synchronization
Cow vs Heifer protocols / Bovine Elite Website/Handout MGA-PG Select synch, Co-synch, Ovsynch Two shot PG (lutalyse) CIDR- progesterone implant Five day CIDR vs seven day CIDR vs ????

27 Estrus Synchronization
Handouts/Internet – Bovine Elite

DEFINITION: deposition of spermatozoa or egg in the female genitalia by artificial rather than natural methods ADVANTAGES: Increases the use of outstanding sires alleviates the danger of keeping several bulls decreases sire cost decreases disease transmission

DISADVANTAGES Requires a skilled technician Requires more money to start Honesty

30 Embryo Transfer Expensive, yet yield rate of improved genetics much faster Donor vs recipient Protocols- Handout ???? Time and labor and facilities Expertise and certification

31 Pregnancy Determination
Ultrasound Heat detection observed Blood Test Palpation stages of pregnancy, Fetal sizes, systematic approach, outline of factors to consider

32 Reproductive Ability - cow
Milking ability-weaning weight correlation replacement heifer selection/handout quality of udders- udder score EPD’s Dystocia

33 Calving/Dystocia Calving difficulty
Normal parturition = three stages – 1) cervical dilation, 2) expulsion of the fetus, and 3) involves expulsion of the fetal membranes Stage 1 labor begins with initial contraction of the uterus and ends when the cervix is dilated and fetal parts (normally front feet and nose) enter the birth canal (usually lasts 2-6 hours)

34 Calving/Dystocia cont.
Stage 2 labor (30 minutes to 4 hours)- begins when the fetal parts enter the birth canal and stimulate the abdominal press. First water bag (chorioallantoic sac) ruptures early stage 2 The second water bag (amniotic sac) is forced through the vulva. Delivery should be completed within 2 hours after the appearance of the amniotic sac at the vulva.

35 Calving/Dystocia cont.
Stage 3 labor is the expulsion of the fetal membranes, usually within 8-12 hours following delivery of the fetus. Assistance should be provided if the cow or heifer has been in stage 1 for > 6 hours, or more than 4 hours for stage 2 labor. Usually use chains, nylon straps, or cotton ropes for pulling calves when needed.

36 Causes of Dystocia Improper selection and development of heifers
Too rapid growth (<1.75 #/day) Don’t feed excess energy - excess fat Genetic influence (birth EPD’s) Improper calf posture as a fetus Cows with small pelvis Problems - retained placenta & expelled vagina Management Considerations

37 Abnormal Presentations
Cattle Normal Presentation Abnormal Presentations


39 Normal Presentation

40 Calving

41 Calving

42 Calving

43 Dystocia

44 Calving

45 Calving

46 Pelvic size in first calf heifers
Calving difficulty score Yearling B. W. Score (cm) (lb) 1 - no assistance 2 - minor assistance 3 – major assistance 4 – caesarean

47 Late Gestation, Dry Period
Increase in nutrient requirements establishing greater fat reserve energy reserve during lactation Problems with underfeeding calf growth calf survival lower milk yield, lower weaning wt. postpartum reproductive problem dystocia, retained placenta, re-breeding

48 Calving interval components
Conception (breeding) Open Gestation/Pregnant (~9.5 mo.) Calving interval components

49 gonadotropin inhibition
Postpartum group Breeding group Uterine involution Peak lactation 45 d 60-90 d Early postpartum stress 1st behavioral estrus Dystocia Retained placenta Uterine infection Metabolic disorders Ovarian cysts Mastitis 1st AI service Suckling -induced gonadotropin inhibition

50 calving 4 Months Early postpartum Gestation (late lactation) Dry 2.1
2.7 1.8 1.4 LACTATION 4 Months Energy (TDN lb/d) 12.8 15.2 11.8 10.2 Protein (CP lb/d)

51 The Effects of Energy During Late Gestation on Calf Growth and Survival
Energy Intake High 14.4 Mcal ME Low 9.3 Mcal ME Item Birth Weaning Survival (%) 100 90 71 Beal, 1996

52 Effect of Body Condition at Calving on Rebreeding Success
Probability of breeding early Probability of Preg. (60-d breeding season) 3 <50% 88% 4 50% 90% 5 60% 94% 6 71% 97% 7 79% 98% Pruitt & Momont, 1990

53 Effect of Energy Level on Postpartum Interval and Conception Rate
Feeding level (pre- & post-calving) % in estrus by 60 d post-calving 1st service CR High – High 80 67 High – Low 81 42 Low – High 45 65 Low - Low 17 33


55 Breeding heifers Breed heifers to calve as two year old (breed one month earlier) disadv: conception rate, %calf crop, dystocia adv: increase one calf per cow lifetime, cow cost/cwt of weaned calf will decrease Replacement hfrs- buy vs raise??????

56 RULES TO FOLLOW with heifers
use small headed bulls (lower epd’s) breed only well developed heifers well balanced ration extra care at calving increase feed at lactation wean early if feasible

57 General age and service of the bull
15 mos matings per year 2 yrs. of age matings per year > 3 yrs. 40 matings per year Reduces after 7 years of age

30-60 days prior to breeding Physical exam- overall appearance including BCS, sound feet and legs, eyes, teeth, hooves, healthiness Repro tract exam-rectal exam of parts – scrotal circumference Semen Evaluation- volume, concentration, motility and viability as well as normality Libido and ability to mate

59 Bull Soundness Exam scoring
Sperm motility- 70% Sperm normality – 70% Must have no abnormalities with seminal vesicles, ampullae, prostate, penis, testicles, scrotum (shape and content), etc.

60 Scrotal circumference guide (minimums, except Brahmans)
Age (months) Circumference (cm) < >

61 Fall vs Spring Calving Spring Calves most natural season utilize summer pasture (good grass) less labor if sold as yearlings, one winter is saved

62 Reproduction of Cattle
Producing fall calves cows are better condition at calving calves escape more parasites, flies, etc. cows give more milk for a longer period calves make better utilization during their 1st spring and summer

63 Rules to follow for higher percentage calf crop
Select older heavier heifers for replacement Proper post weaning care – don’t overfeed Select from cows with high reprod. Perf. Breed heifers 30 days earlier Check the cow herd 3-4 X daily during calving Develop adequate working facilities Pregnancy check Maintain herd health program

64 Rules to follow for higher % calf crop cont.
Develop and easy ID and record keeping system Breed heifers to bulls with small birth wts. Separate heifers calving as two year old from mature cow herd Provide adequate nutrition Observe the cow herd frequently during breeding Develop a definite breeding and calving season

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