Small Rum 1 Flashcards
In terms of reproductive performance in sheep flocks at what 7 stages do you measure
1) pre-joining
2) gestation
3) ferilisation
4) early gestation
5) later gestation
6) birth -0-3 days
7) lamb marking
How do you measure reproductive performance on a farm during pre-joining, gestation and fertilisation and common issues
1) Pre-joining - Enter oestrus but not as much ovulation - fewer multiples
- One of the most important ones in sheep industry
2) Gestation - failure of insemination -> ram unable or unwilling to inseminate the ewe
- Now get increase in returns to service and fat rams (not as much activity)
3) Fertilisation - If ram the issue -> less maiden ewes (about 2 years old) pregnant
- Toxic problem and accumulative generally problem in older ewes (decrease pregnancy)
How do you measure reproductive performance on farm during early gestation and what is important about this stage
pregnancy diagnosis in second trimester so will come up then
- Few pregnant and aborted foetuses (generally don’t find aborted foetuses)
PRENGNANCY SCANNING -> first time can check for losses from ovulation to early gestation
- Unsure on when reproductive failure has occurred
How do you measure reproductive performance in late gestation, birth 0-3 days and lamb marking. which is most important
1) Later gestation - aborted foetuses are the clinical signs - again don’t see often
2) Birth + 0-3 days - due to perinatal ability of the mother (colostrum, weather etc), will see via dead newborns and low marking %
3) LAMB MARKING -> 1-2 weeks after lambing marking occurs - second time can check for reproductive failure
What are the 4 main reasons ewes might be in anoestrus in pre-joining
- Haven’t reached puberty yet
- Too young
- Too lightweight - want them to be 75% of their adult standard weight - Have reached puberty but are currently low bodyweight/CS
- Wrong time of year
- Short-day breeders (extent varies with breed)
- Less seasonal breeds can be induced with ‘ram effect’ - Some toxins affect reproductive hormones & suppress oestrus
- e.g. coumestans from lucerne/white clover
How to tell that ewes are in anoestrus at pre-joining and what influences anostreous if ewes old enough what is the main determinant of anoestrus
Anoestrus ewes show no mating activity
- Won’t be observed standing to be mated by rams
- Won’t be marked by rams wearing mating harnesses
If ewes are old enough, right and no toxins still depends on CONDITION SCORE
- Aim at condition score 3 mating and lambing
○ Increasing condition score = fewer dry ewes, more twins
- Short-term increased protein intake pre-mating (flushing) also increases conception rate
- 1 extra CS = extra 10-20% lambs born
What are the 4 main reasons rams may not inseminate ewes
- Poor libido
○ Merino - high libido 1 ram per 100 ewes
○ Suffix - 2-3% - Balanoposthitis (‘knob rot’)
○ Treat symptomatically/ topically (antibiotics if severe) - Musculoskeletal problems discourage/prevent mounting
- ‘5 Ts’
– Teeth - need to be able to eat
– Torso - condition score 3.5 prior to mating -> will lose some weight
– Toes - not lame
– Tossle - penis and prepuce
Top 3 failure of insemination
– (Testes) - failure of conception (Fertilisation)
What are the 2 reasons rams may mount ewes but not fertilise and how to prevent this
- Poor sperm output
- Not enough testis (size, no. rams) for ewes! - Poor semen quality
- Heat: fever, scrotal mange
- Orchitis e.g. brucellosis
Diagnosis, treatment, prevention:
- Use ‘1%+1’ fit, healthy rams
- Always use pre-mating Breeding Soundness Examination (5 Ts)
What is a common disease cause of failed fertilisation in male, why does it lead to this, what lead to in females and transmission
Ovine Brucellosis (Brucella ovis)
- Mainly male infertility
○ Epididymis & testicular granulomas (shrink) after inflammation (swelling) -> asymmetry of testicle
○ Ewe abortions rare(?)
- Spreads male to male
○ ± mechanical transmission via served ewes -> 1 day to a week the bacteria can last in the vagina
Homosexual behaviour between rams -> transmission
Ovine Brucellosis (Brucella ovis) how present and treat
- Lifelong infection, refractory to treatment
○ Acute phase - fertility 0% but chronic infection -> regains some fertility
§ Clinical presentation -> initially large decrease then years of suboptimal fertility in rams
○ Need to eradicate
○ Accreditation schemes exist
Ovine Brucellosis (Brucella ovis) what are the 3 main options for eradicating and which recommended with pros and cons, also what diseases look like this and therefore should be tested for
- Cull all rams & replace from accredited flock
○ High changeover cost - OR test & slaughter - most common (described below)
○ Palpate & serology q 14- 21 d.
○ Two negative tests 30 & 90 days after last cull -> takes a while to seroconvert - Two flock system - not recommended
○ Keep existing rams
○ Buy new clean rams and keep separate
○ Slowly cull existing infected rams
§ Pros - not high changeover cost, may not be able to get all new rams in time for breeding season
§ Cons - need to keep them COMPLETELY SEPARATE -> high risk
Disease ○ Histophilus ovis, actinobacillus seminis, haemophilus somnus -> LOOK LIKE BRUCELLOSIS SO WORTH TESTING FOR IF ACCREDIATED BUT HAVING EPIDIDYMITIS
Ovine Brucellosis (Brucella ovis) diagnosis and intervention timeline what are the 8 steps
- Suspect -> low/variable %, testicular abnormalities found during BSE
- Test rams - palpation, serology: some/all rams
- B. ovis positive
- Put rams in small groups - minimise the spread while get test and cull programme going
- Test and cull -> repeat for 2-3 weeks
- All negative test result
- Final ‘free’ test 1-3 months after all-clear
- Other considerations -> assess biosecurity, enter a state accreditation program (not for commercial flocks)
What are some causes of failure of fertilisation of the ewe with return to service or without return to service
- With return to service
○ Something impairs sperm fertilising egg but doesn’t disrupt normal oestrus cycle
○ EG - oestrogenic clover, mating young ewes (ovulation not well timed with oestrus behaviour) - Without return to service
○ Ewes not pregnant but no longer cycle
○ EG - if mating period coincides with beginning or end of normal breeding season
§ OR oestrous may cease if ewes are under severe nutritional stress
○ Pregnancy loss after maternal recognition of pregnancy looks the same as this
Oestrogenic clover what is the disease caused by, what occurs and clinical signs
Clover disease caused by phytoestrogens
- Impaired sperm transport or chronic uterine change
Clinical Signs
○ More older dry ewes - decrease fertility in older ewes
§ Accumulative effect -> longer exposure in older ewes so permanent infertility
○ Increased teat length, precocious lactation, enlarged genitalia in wethers & dry ewes
○ Vaginal, uterine prolapse (& ewe & lamb mortality)
Oestrogenic clover disease diagnosis and treatment
Diagnosis ○ Identify clover ○ Wether teat length assay ○ Uterine histopathology -> cystic endometrial hyperplasia - not common Treatment ○ Avoid risk pastures near joining ○ Cull at younger age(?) ○ Graze cattle ○ Reduce stocking rate (to ↑ grass & ↓ clover) ○ Pasture renovation
Embryonic or foetal loss clinical signs and causes d12
- Early embryonic loss looks like failed fertilisation with no return to service
- May miss abortus if in early pregnancy (<3 months)
- Ewes often OK
- May see prematurely born lambs if late abortion
d. 12
1. Selenium deficiency (NZ)
2. Onion grass poisoning - toxin fron fungus, can also cause neurological signs
3. Pestivirus
4. Listeria monocytogenes
5. Toxoplasma gondii
6. Campylobacter
List the 3 main infectious causes of foetal loss and what do they all have in common
1) campylobacter
2) toxoplasma
3) listeria
- all zoonotic
- all oral
Campylobacter how transmit, what occurs with infection, diagnosis and treatment
- when give birth shed organism and ewes that become exposed to environmental
○ If pregnant will abort and then will get lifelong immunity - ALSO - leads to target lesions on the liver
§ Main issue in maiden ewes with abortions -> just vaccinate these
○ If not pregnant then just get lifelong immunity - Culture - very hard to culture but SMEAR - will see the typical shape -> important diagnosis
- a/bs - antibiotics -> generally resistant to broad spectrum antibiotics -> HARD TO MANAGE OUTBREAK WITH THESE
Toxoplasma how transmit, what occurs with infection, diagnosis, treatment and prevention
oral exposure to oocyst in cat faeces (generally younger cat)
- Protective immunity again important - so abortion depends on if pregnant when first exposed
○ Again main issue with maiden ewes -> so just vaccinate these (only in NZ)
- Foetal brain - good to find histology signs, maternal serology also important
- Treatment -> may not work as well if foetuses are already dying -> not 100% effective
- Prevention -> manage contact between ewes and cats -> exposure BEFORE PREGNANT
Listeria transmission, what age occur, diagnosis, treatment and prevention
- ubiquitous in the environment -> delivery of infection through a source - predisposing factors are important
- Exposure doesn’t lead to immunity therefore can occur at ANY AGE GROUP
- Organs for histology, culture foetal brain membranes
- Treatment - antibiotics (penicillin or oxytetracycline)
- Prevention - manage feed sources and general ewe health
Define pregnancy rate and conception rate, possible value, normal range, when measured and how to increase
Pregnancy rate
- No. ewes detected pregnant/ No. ewes mated x 100
- 0-100%
- >95%
Conception rate
- No. foetuses detected/
No. ewes mated x 100
- 0-200%+ (triplets)
- 95% (single lambing merinos) 150+% - fecund breed
- Measured at pregnancy scanning - later than bovine or equine
INCREASE - via nutrition (body condition score) at mating
Define lambing rate and marking rate, possible value, normal range, when measure and how
Lambing rate - No lambs born/ No. ewe mated x 100 - 0-150+% - 95-150+% - Could be measured in the post-lambing period by regular counting of lambs, must include detection of dead lambs (hard to count)
Define marking rate and weaning rate, possible value, normal range, when measure and how
Marking rate
- No. lambs marked/
No. ewes mated x 100
- 0-100+%
- 70 (merinos) - 150%
If <65% flock won’t breed enough to be self-replacing
- Count from lamb marking (2 weeks after end of lambing)
Large loss generally between lambing and marking - due to hypothermia, bad mothering etc.
Weaning rate
- No. lambs weaned/
No. ewes mated x 100
- 0-100+%
- 70-150%
- Usually little change from marking to weaning, except if outbreak of infectious disease eg tetanus
What are the 4 ways to influence the oestrous cycle
1) melatonin
2) ovastim vaccination
3) PGF2 alpha
4) glucocorticoids
What does melatonin and ovastim vaccination do to the oestrus cycle, is it recommended and when use
- Melatonin
○ Increase GnRH -> starts cycling and more follicles in the wrong season
○ Trade name: Regulin - Ovastim vaccination
○ Protein specific to negative feedback mechanism is in vaccination -> immune system destroys theses
○ Reduces androgen via -ve feedback -> more follicles -> increase amount of ovulation per cycle
○ Not recommended -> can improve the fertility but without increases nutrition -> results in increase undernourished and dead lambs
§ ONLY USE IF CONDITION SCORE IF PERFECT
§ Better in cross-breeds as generally larger lactation so can provide for the increase in number of lambs
PGF2alpha and glucocorticoids what do they do to the oestrous cycle and when use
- PGF2alpha
○ Luteolytic (day 5-50/150 - end of first trimester or up to first half of pregnancy)
§ Regression on corpus luteum and at this point of cycle only source of progestagens so abortion
○ Goats -> don’t have placental take over for production of progestagens so give PGF2alpha ANYTIME in cycle and will result in abortion - Glucocorticoids
○ Induce parturition in the last 10 days of pregnancy
§ Cattle: GCs work for longer time before normal calving
○ Only do to save the ewe under strict
What are some breed differences that help with breeding outside season
- ALL breeds naturally in oestrus in winter APRIL - JULY - GENERALLY MOST FARMS ARE HAPPY
- Merinos aren’t as seasonal so higher percentage in oestrus during other months
○ Depth of anoestrus reflects how easy it is to induce cycling at these times
§ MERINO is the easiest
What are the 2 main techniques for getting merinos to breed all year round
1) exposure to males can induce oestrus
2) regulin - increases out of season cycling and ovulation rate
Exposure to males to induce oestrus what is needed from males, and how to perform - when come into oestrus and therefore when to mate and AI
- Males showing sexual behaviour and secreting pheromones
- Males and females needed to have been separated for >500m for 3-4 weeks
1. Most ewes ovulate after ram intro BUT NO OSTREUS (won’t allow mating) - don’t have progesterone primed brain
2. About half of the sheep CL regresses quickly and have normal cycle 17 days later - in oestrus - Other half of sheep CL regresses normally and have normal cycle 19 days later - in oestrus
- THEREFORE -> 3 weeks after introduction of rams will see sheep in signs of oestrus
- Not good to synchronise animals -> 1 week spread of variation of ovulation THEREFORE GOOD ENOUGH FOR NATURAL MATING NOT GOOD ENOUGH FOR ARTICFICAL INSEMINATION
What are the 2 main types of teaser ram/bucks should you use with exposing ewes to males to induce oestrus and which shouldn’t you use
a. Surgical vasectomy
§ Not fertile but still producing testosterone so still showing sexual behaviour
b. Testosterone-treated wethers
§ Long-acting testosterone and will induce male sexual behaviour
§ RESTRICTION ON THE USE -> only registered for use in AI programs or pizzle rot prevention
- Shouldn’t use fertile rams because will then get a very long mating period -> BAD FOR MANAGEMENT
Regulin how given to the ewes, what does it do and what need to ensure
- Subcutaneous implant that slowly releases melatonin
- Stimulates out-of-season oestrus cycles
○ Premium prices for autumn lambs
○ Still works best in less seasonal breeds - merino - Still must separate ewes and rams before
- Reduced ovulation rate afterwards if missed joining
Feed kgDM needed for late pregnancy grazing or triplets and at lambing CS
- Late pregnancy ○ Grazing 900-1000kgDM/ha FOO (-3cm+) ○ Triplets: 1100-1200kgDM/ha (4cm) - At lambing ○ Ewe CS 3.2 ○ Grazing > 1800kgDM/ha FOO (6cm)
Pregnancy diagnosis how done, what day, what looking for and cost
- Ultrasonography
- Day 50-100
○ Empty/single/twin -> looking for cotyledons - Lay contractor: 50-80 cents/ewe
What are 6 important background influences on male reproduction
1. Age ○ Puberty, Sexual maturity ○ fertility - bell shaped curve -> generally 12 months of age ○ Senescence - old age 2. Season ○ Remember rams short day breeders! 3. Social interacting rearing 4. Environmental factors ○ Pastures - oestrogenic pastures ○ Pollutants - heavy metals and fracking ○ Predators 5. Nutrition ○ Bodyweight effects 6. Management factors ○ Time of joining, length of joining ○ Handling at mating ○ Male to female ratio ○ Factors around semen handling, storage and insemination in AI programs
what examining in a ram for scrotum and contents, what is important and what do you what the consistency of the testicles to be
- Scrotal skin
- Cords
- Symmetry
- Testicular size
- Testicular consistency
- Epididymis: head body and tail
Size of testicles
- Scrotal circumference
- Ranges Adult >32cms, lambs >30cm
Consistency of testicles - FIRM AND RESILIENT
what is a common what to collect semen, what useful for, discomfort levels
electroejaculation
- Rectal probe delivers electrical stimulus to nerves and tissues controlling ejaculation
- Useful/practical for collection in large numbers of rams (assess ram teams, pre-sale)
- Level of discomfort/pain comparable to that of handling alone
Examination of semen in field what are the important aspects and which stain used
- Volume.
- Concentration,
- Morphology
○ Small amount of abnormalities is normal - Estimate “Wave motion”
-> RAPID SWIRLING WAVES - in low power - MOTILITY= % moving actively forward
○ Want minimum of 30% - Examination of semen in the laboratory - we now send it off
○ Sample for concentration:
§ Nigrosin eosin stained smear
□ Estimates % live sperm (no stain - dead sperm takes up the stain)
What are the 2 main congenital abnormalities that lead to reproductive disorder, uni or bilateral and what result in
- Testicular hypoplasia - bilateral or unilateral
○ Smaller testes results in lower concertation of semen, lowered motility, not as firm or resilient
○ Could have normal head morphology or abnormal midpiece/tail morphology - Cryptorchidism - unilateral
○ Can still be fertile in the other testicle - difficult to tell by looking at the sperm
What is the main acquired abnomrlaities that is a reproductive disorder, result of infection and treatment
- Scrotal mange - chorioptes bovis
○ Local increase in scrotal skin temperature resulting from inflammation
○ Exudative inflammation, thickening of scrotal skin, scaly, crumbly
○ Impairment of heat loss cause of testicular degeneration
○ Treatment: MLS - moxidectin, Ivermectin - repeated treatment
What are 2 reproductive disorders that can be acquired or congenital, causes, result from infection and types if applicable
- Testicular degeneration
○ Acquired or congenital - thermoregulation failure to occur
§ Can be due to pyrexia or local inflammatory process, wool covered scrotum (reduces evaporative cooling)
○ Abnormal sperm and decreased scrotal circumference
○ Reduced fertility often infertile if severe - Spermatic granulomas
○ May result from acquired injury (nothing last year) or congenital defect (more likely in younger rams)
○ Any condition that causes leakage of spermatozoa or Spermatozoal antigens into the extratubular compartment is potentially complicated by this reaction
○ Spermatozoa incite - a granulomatous/pyogranulomatous response
○ Spermiostasis -> may result if granuloma blocks the efferent tubules in the ram
§ If bilateral -> will see semen but no sperm within
