Small ruminant breeding Flashcards
what is a ram marker harness? how do we use it?
§ male, teaser male, androgenized female
§ To determine if return to estrus
§ Only useful in season but
§ Poor predictive value
methods of preg diagnosis in sheep and goats?
§ Ram marker harness
§ Udder palpation
§ Abdominal ballottement
§ Biopryn ELISA
§ Ultrasound
Goat specific:
§ Digital palpation of cervix
§ Estrone sulfate in serum, urine or milk
when can udder palpation be used to diagnose pregnancy
§ Last few weeks of gestation
when can abdominal ballottement be used for pregnancy diagnosis?
After 110 to 120 days gestation
when can we use Biopryn ELISA to diagnose pregnancy and how does it work?
– 30 days post- breeding (Pregnancy Specific Protein B)
what are pregnancy diagnostic methods that can be used in goats but not sheep?
§ Digital palpation of cervix
§ Estrone sulfate in serum, urine or milk
when can digital palpation of cervix be used to diagnose pregnancy in goats?
Before 30 days
-After 30 days gestation can no longer feel
when can estrone sulfate in serum be used to diagnose pregnancy in goats
urine or milk
§ After 50 days gestation
when can we count fetuses in small ruminants? what is the process and technique?
§42 days after male removed
§ 50 to 90 days of pregnancy
§Hold off feed overnight
§Dry wool
§Handling facilities
Ultrasound:
§Curvilinear probe
when can we count fetuses in small ruminants? what is the process and technique?
§42 days after male removed
§ 50 to 90 days of pregnancy
§Hold off feed overnight
§Dry wool
§Handling facilities
Ultrasound:
§Curvilinear probe
why is it important to count fetuses?
Feeding ewes on the basis of litter size (+ body condition, parity)
goat cycle length
21d
sheep cycle length
17d
what is considered breeding success?
UNSYNCHRONIZED IN SEASON
Pregnancy rate to first cycle: 70 – 80%
Pregnancy rate over breeding period: 95 – 100%
SYNCHRONIZED
Pregnancy rate in season: 60 – 70%
Pregnancy rate during anovulatory season: 50 - 70%
What do you think is wrong if…
§These does were scanned at 55 to 80 days of gestation and
§80% found evidence of a pregnancy
§5% no evidence of a pregnancy
§15% found a large black echo on U/S with no structures
Caprine False Pregnancy
Caprine False Pregnancy; how common? presentation? diagnosis? treatment?
§Cloud burst / pseudocyesis
§Common – up to 10% of herd
Presentation:
§ Anestrus
§ Enlarged abdomen
§ May be no breeding history
Diagnosis:
§ U/S – no placentomes or fetus
Treatment:
§ PG – single or double treatment
A goat client with a “pet” herd
§Noticed kids born with abnormal external genitalia
§About 13% of the kids born are abnormal
§What do you think is going on?
Intersex with polled condition
what is Intersex with polled condition in goats? how does it arise and how common is it?
§Polled X Polled breeding
§25% of doelings are PP doelings:
> May be true hermaphrodites
> May be pseudohermaphrodites
> Range from phenotypic females with or without masculinized sex organs to phenotypic males
§25% of bucklings are PP bucklings
>Often sterile with sperm granulomas
how common is intersex in ewe lambs in mixed pregnancies?
Intersex in ewe lambs occurs ~ 5% of time in mixed sex pregnancies (freemartism) and also occurs in goats
Caprine Cystic Ovarian Disease; how does it present?
Presents as anestrus / persistent estrus / irregular cycles
Caprine Cystic Ovarian Disease; treatment
§ HCG (500 iu) or GNRH (100 to 250 iu)
§ PGF2α 9 days later
Caprine Cystic Ovarian Disease; what types of irregular cycles might we see and when are they worse? how can we improve things?
§ Shortened or lengthened / split heats
§ Worse at beginning & end of season
§ Teaser doe or buck will improve
§A client with both sheep and goats housed together calls and asks if his buck breeds the ewes, will they give birth to “geeps”?
§What do you think?
§ Rams will breed does
§ Bucks will breed ewes
§ Only does will conceive
§ Most abort < 60 days with occasional negative outcome for the doe
§ Live births are very rare
§ 57 chromosomes (54 in sheep versus 60 in goats)
§ True geeps are very rare!
- The owner of a small flock of sheep comes to the barn in the morning and finds that the ram lambs intended to be sold that week to market have broken into the ewe pen
- He sees some breeding activity between mothers and sons– what should you advise?
Induction of Abortion
§Wait 11 days from the event to make sure active corpus luteum
how do we induce abortion in a sheep after a breeding event?
§Wait 11 days from the event to make sure active corpus luteum
§ Sheep
§ < 50 d gestation PGF2α
§ > 50 d gestation, PGF2α + dexamethasone once/day for 2 to 3 days
how do we induce abortion in a goat after a breeding event?
§Wait 11 days from the event to make sure active corpus luteum
Goat
§ PGF2α at any stage of gestation
when should we induce parturition in sheep? how?
§When breeding dates are certain – post 142 d gestation
§Concentrate lambing / kidding for labour, facilities
Sheep:
§ Dexamethasone i.m.
§Will lamb 24 h to 72 h later.
§ PGF2α will not work as pregnancy not CL dependent
when should we induce parturition in goats? how?
§When breeding dates are certain – post 142 d gestation
§Concentrate lambing / kidding for labour, facilities
Goat:
§ Dexamethasone i.m.
§ Results variable 7 to 10 d
§ PGF2α will work as well as pregnancy is CL dependent
§A sheep flock of 200 ewes, induced estrus out of season using MGA and eCG
§After 14 days on MGA and 500 iu eCG, 10 rams were added to the group 24 hrs later
§The pregnancy rate when scanned 60 days later was only 30%
What could have gone wrong?
not enough ram power!
How many rams are needed?
Breeding Situation:
Mature – breeding paddock 1:40 to 1:80
Yearling – breeding paddock 1:20 to 1:25
Mature – rough terrain 1:20 to 1:30
Mature – transition synchronization* 1:20 to 1:25
Mature – synchronized in season 1:10 to 1:15
Mature – synchronized out-of-season 1:5 to 1:7
- When using ram effect
How do we know if the problem is the ram?
Male Breeding Soundness Evaluation
Male Breeding Soundness Evaluation; how often
BSE should be done
§ Pre-breeding at least annually
§ If suspect a problem
§ Prepurchase
Male Breeding Soundness Evaluation; components
Components
§ Physical examination of the animal
§ Examination of the scrotum and contents
§ Examination of the prepuce and penis
§ Semen collection and inspection
BSE – Physical Examination
Feet
§ Straight and clean and no footrot or deformity
Legs
§ No signs of malformations
§ No chorioptic mange
§ Soundly moves out
Teeth
§ No over or under bite or loss of premolars
Eyes
§ Clear, no evidence of entropion or pinkeye
§ No other evidence of disease conditions
what should small ruminant scrotal circumference be
> 70 kg
30 cm SC
> 110 kg
36 cm SC
BSE: Examination of the testes; what should we see, and what should we look out for?
§ Freely moveable from the scrotum
§ Uniform in size
§ Firm to touch but not hard or
lumpy
§ Orchitis = swelling, hard, draining tracts
> Actinobacillus seminus
§ May be hypoplasia secondary to injury or infection
BSE: Examination of the epididymides; what do we want to see and what should we look out for?
§Tail easily palpable but soft, uniform
§Head also palpable, feels softer and smaller
§Hard lumps or increased size indicates inflammation – epididymitis
§Brucella ovis
Chorioptes bovis is often found where? what does it cause?
Chorioptes bovis (sheep / goat strain) is commonly found on fetlocks and pasterns as well as scrotum
§ Heats testicles and causes subfertility of rams and bucks
Balanoposthitis (Pizzle rot); cause
Corynebacterium renale + high levels of urea in urine (high protein diet)
BSE: Semen Collection Techniques
Electroejaculator - sheep only ?
Artificial Vagina - sheep and goats
BSE: Semen Characteristics
Volume (ml)
Total sperm/ejaculation (x109)
Sperm concentration (x109/ml)
Motile sperm (%)
Normal morphology (%)
Mounting each other is common in group housed rams. Can cause:
ascending orchitis / epididymitis
how common is a buck with low libido?
A buck with poor libido is unusual!
Teaser Bucks and Rams; what are they? how do they come about?
Select sexually experienced, healthy male
* Vasectomy
* Epididectomy
* Not too big
Other methods
* Androgenized female or castrated male (wether)
> 100mg testosterone proprionate once/wk for 3wks
> good for 4-8wks
* Penile deviation is rarely done
