Large Animal Clinical Reproduction

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Large Animal Clinical Reproduction by Mind Map: Large Animal Clinical Reproduction

1. Applied Endocrinology

1.1. Reinstating reproductive activity in adult healthy animals - induce oestrous/ovulation

1.1.1. Seasonally anoestrous ewe Continuous GnRH infusion - pulsatile fashion PMSG/eCG injection at P4 sponge removal Photoperiod/melatonin implants (dark hours) Ram - seperate for 4 wks, oestrous, ovulate - prime with P4 sponge/IM 3-5 days before

1.1.2. Anovulatory post-partum cow True anoestrous, correct underlying problem (NEB, maternal bond, disease) PRID/CIDR - 12 days - removal = inc LH PRID/CIDR - 12 days +500 iu eCG on day of removal

1.1.3. Sustained increase in LH pulse fq

1.2. Induction of puberty in gilts

1.2.1. PG600 (PMSG + hCG) IM LH and FSH Pre-pubertal gilts - induce puberty, prevent delayed puberty (6-7 mnths, 100kg; >8mnths) First litter sows - prevent anoestrous On day of weaning Multi-parous and first litter - treat anoestrous, 8-10 days after weaning Multi-pparous, first litter sows (seasonal anoestrous) - prevent anoestrous (Seasonal) On day of weaning

1.3. Synchronisation of oestrous/ovulation

1.3.1. Fixed AI time, high pregnancy rate Control luteal phase and/or follicular growth Progesterone - induce CL lysis, make dominant follicle ovulate PGF2a - control/shorten luteal phase - 10 days - 1-5 days too early, CL unresponsive Injection technique, may do two AI fixed time once/twice Not very effective Ovsynch = follicular wave synchrony (GnRH), shorten luteal phase (PGF2a) - heavy dose bolus, follicle utilised - 7 days after, PGF2a, lyse CL, synchronise LH surge with GnRH at day 9, AI day 10 Effective, expensive Follicle wave synchrony with P4 + extend luteal phase (PRID/CIDR + PGF2a) PRID at day 8, one day before develops, add PGF2a, stop development

1.4. Embryo survival

1.4.1. Progesterone supplementation - varied effect Less than 6 days from AI then effective, otherwise little effect for pregnancy establishment

1.4.2. Luteal deficiency/poor maternal recognition Progesterone supplementation GnRH day 11 (cows); day 9 (ewes) Herds with low pregnancy rates

1.5. Treating Reproductive Disease

1.5.1. Cystic ovarian disease - ovulatory mechanism defect, failure of pre-ovulatory LH Stress, low oestradiol conc., low hypothalamic sensitivity to oestradiol Uterine infection NEB Luteal cysts - prostaglandin - heat 3-4 days later Follicular cysts - GnRH/hCG - luteinise cyst Pyometra - persistent CL - PGF2a Pseudopregnancy - persistent CL

1.6. Control Parturition

1.6.1. Cow, sheep, goat, sow - foetus must stop prog. production by CL/placenta - parturition = foetal pituitary-adrenal axis Foetal stress = ACTH, inc. cortisol, inc. oestrogen:progesterone ratio, CL regression, inc myometrial contraction, cervical dilation etc.

1.7. Increased Gamete number

1.7.1. Inc. follicular recruitment = FSH Recombinant FSH (superovulation of donor) Then inseminate Varied response

1.7.2. Nutrition - inc. nutrition before mating - high energy, lower oestradiol concentration, promote FSH release (less negative f/b)

1.8. Immunological control

1.8.1. Immunisation against androstenedione (remove -ve f/b) - single dextran adjuvant injection, increase ovulation rate in ewe Fecundin, Androvax plus, Ovastim

1.8.2. Vs GnRH - inhibit gonadotrophins and gonadal steroids, reduce testicular size, function Control aggression, male odours Vaxstrate - calves Equity - horses Gonacon - deer Improvac - boar SpayVac for others, + wild - bind ZP, sperm cannot bind

2. Fertility in cows

2.1. Calving every 12 months - all year round Or seasonal periods

2.1.1. 12 month period = optimal milk Seasonal - milking reliant on pasture

2.1.2. Pay-off between fertility and milk yields

2.2. Sub fertile = fails to reach target

2.2.1. Structural, functional, management, infectious causes No observed oestrous, regular/irregular returns to oestrous after AI, abnormal vulval discharge, abortion, still birth No oestrous - congenital abnormalities = no puberty Other reasons for no oestrous Cow/heifer - oestrous every 18-24 days unless pregnant or 4-6 weeks post-partum Ovarian cysts - >2.5cm, persists more than 10 days, form anovulatory Graafian follicles - granulosa cell layer degenerates, cessation of normal cyclic activity = cow becomes acyclical or nymphomaniacal No calving after service?

2.2.2. Infertile = sub-fertile or sterile Increasing over time

3. Herd Fertility

3.1. Optimal = one calf per cow per year

3.2. Calving interval

3.2.1. Voluntary Waiting Period (VWP) = Earliest service date after calving = 42-55 days Too early, lower pregnancy rates Too late, wasted time Average value - cows not served missed, large spread not seen Calculate 1st service (24d) submission rate (day 50 post calving)

3.2.2. Calving-First service interval (average 65) VWP, post-partum problems, return to cycle, oestrous detection

3.2.3. Calving - Conception interval (average 85) Oestrous detection, pregnancy rate Detection - affects submission rate, inter-oestrous intervals Inter-oestrous interval - more than one service - should be around 21 days - sums up how good oestrous detection is Some late, some 48 days (missed) If random distribution of early, late etc. then suggests human/detection error Can also milk sample at AI, test for progesterone - should not be high at AI Cu-sum graph - shows trends, see how good pregnancy detection is and how it varies - point to causes?

3.2.4. Conception rate (55-60%) 120 day In Calf rate - most should - benchmark of 64% 210 days Not in Calf - <7% Regular monitoring - routine visit: Exam animals, records, advice Animal problems: Retained foetal membranes, metritis, Vulval discharge Post-calving/pre-breeding checks Irregular inter-oestrous intervals Oestrous not observed, pregnancy diagnosis - US and manual palpation Records: Key indices, oestrous detection, pregnancy rates

3.2.5. Calving index - average calving interval of all cows in a herd at a given time (days) - historical figure, hides those culled/lost animals - target 365 days

4. Sheep Infertility + Goats

4.1. Fertility

4.2. Fecundity

4.3. Survival rates

4.4. Lambing percentage

4.4.1. Poor % = poor conception rates, poor ovulation rate, high embryonic/foetal loss, abortion/still birth/perinatal loss Single lambs - ovulation Barren ewes - conception rate, embryonic/foetal loss Less Ewes rearing lamb - abortion, stillbirth, death Conception rate Ovulation rate Embryonic/foetal loss Late foetal death - overfeeding (early pregnancy) - placental insufficiency Or underfeeding (late pregnancy) w/ poor BCS Abortion/Still birth/Perinatal loss

4.5. Targets - different per breed, season, environment Vs MLC Flockplan records for local area/breed

4.5.1. Planning for next year! Pre-mating exam - male fertility, BCS, health Mating harnesses? Flushing Pregnancy scanning Submission of aborted foetus (cause)

5. Nutrition in Pregnancy

5.1. Water - Quality, clean, cool, access Also water in feed - palatibility and utilisation

5.1.1. Lactation, season, temp

5.2. Metabolisable Energy (ME) - 1 Calories = 4.2 Joules MJ = 1,000,000J

5.2.1. Energy requirements: 1 litre of milk - 5MJ/litre Maintenance (700kg) = 72MJ/day Activity - high level = 19MJ/day Pregnancy - increases nearer later stages 0.5 - 44MJ/day Pregnancy toxaemia in cattle - much less common vs sheep Dry cow off at same BCS 3 Dont want too fat cow at calving Alter BCS during late lactation - do not reduce diet during dry period! Growth, cold weather etc. Breeds, milk composition Weight loss - 1kg/day = 35MJ BCS - Spinous process, eye muscle, transverse process, back bone, skin, fat cover Protein Rumen degradable protein (RDP) - ammonia, energy, carbon fragments Rumen undergradable protein (UDP) By Pass Protein High source (protein meals, soybean, cotton seed, fish meal, NPN) Moderate (Alfalfa, legume hay) Low (Grass hay, cereals, straw) Minerals and Vitamins Macro vs Micro, production demands (calcium), balance, interactions Lactating mineral to dry cows as milk fever more likely

5.2.2. Main source of energy = Cereals Although get SARA/acidosis if too much By product feeds also has high source of energy Moderate = TMR, Maize silage, haylage, good quality pasture, good quality hay Grass ME = 10-11 MJ/kg Low - low quality hay, low qual pasture, straw, by products

5.3. Acidosis

5.3.1. Highly fermentable carbohydrate - sub-acute ruminal acidosis/ruminal acidosis Acidosis SARA

5.3.2. Voluntary Feed Intake/ Dry Matter Intake Kg/day DM Appetite, may not be able to meet energy demands, reduced around calving-late pregnancy and early lactation Reduced in fat cows (also calving/early lactation) Ketone bodies increases as energy deficient, loss of BCS Feed: Palatability, Fresh, Heated, Mouldy, Trough space How much actually being fed? Fresh and palatable enough?

5.4. Sheep

5.4.1. Gestation = 144 days/20 weeks Need nutrition, no abrupt changes, minimise embryo loss Separate feeding for groups

5.4.2. BCS - fat coverage - handling Too fat - dystocia Too thin - health at risk - sudden demands of lactation after lambing - can't keep up

5.4.3. Pregnancy Diagnosis From 40 days gestation (wks 11-15) - number of foetuses - management and feeding of pregnant ewe Different amount of food/concentrates depending on how many lambs

5.4.4. Pregnancy toxaemia/twin lamb disease Excessive energy demand, severe NEB Late/on point pregnancy, Recumbent, neuro signs, twins/triplets, stress Life threatening, poor prognosis Reduce energy demand (induce abortion via corticosteroid, although endometritis risk) Energy source into ewe - IV glucose, Oral propylene glycol, oral electrolyte carbohydrate source (liquid lectade)

6. Pregnancy diagnosis

6.1. Management: Stage of pregnancy, accurate timing for drying off, date of parturition, number of foetuses (correct feed)

6.2. Methods

6.2.1. Non-return to oestrous in polyoestrous species

6.2.2. Measure hormones/other substances

6.2.3. Detect gravid uteris and contents - manual palpation, US, radiography

6.2.4. Identify gross and microscopic changes in genital system structure - not that useful

6.3. Cows

6.3.1. Early pregnancy: after service, 90% fertilised oocyte Interferon Tau, stop leuteolysis Embryo loss, <21 days loss 22% 21-42 = 6% 42+ = 5% Non-return to oestrous = 18-24 days B-mode real time US from 30 days Progesterone in plasma and milk 21-24 days Milk progesterone assay: Potassium Dichromate Tablet (preservative), Lactab, 4 degrees, ELISA - better than plasma More for non-pregnancy rather than preg - more likely to be false positives (other factors for +ve PG)

6.3.2. Membrane slip - palpation of chorionallantois from 33 days - accurate, but take care not to induce abortion Disparity in horn size - unilateral cornual enlargement with fluctuation, thin uterine wall from 35 days Foetus palpation 45-60 days Placentomes (caruncles.cotyledons) from 80 days Hypertrophy of middle uterine artery from 85 days in broad ligament (Fremitus) - can be confused with pulse in other arteries Oestrone sulphate in milk and plasma from 105 days (120 ideally) Disparity in horn size care - incomplete involution (takes 28 days), fluid in horns, pus (pyometria), mucous, watery

6.3.3. Ultrasound Transrectal, favourable lighting, high FQ and resolution, biosecurity Alongside manual palpation Not 100% - scan ovary from all sides See fluid, embryo, placentomes, amniotic sac etc.

6.3.4. Oestrone Sulphate - oestrone produced by feto-placental unit - sonjugated to sulphate in fetal liver - blood sample from 120 days (possibly 105)

6.4. Ewe

6.4.1. Non-return to oestrous 16-18 days after service Plasma progesterone 15-18 days Transabdominal B mode US (as early as 30 days, foetal numbers 45-50 days) Doppler US transabdominally (not anymore) Vaginal biopsy (research) Palpation of caudal uterine artery - no Radiography - pet sheep

6.5. Goat

6.5.1. Failure to return to oestrous - 21 days after service Milk/plasma prog. 21 days (false +ve in pseudo) Oestrone sulphate in plasma/mlik from 50 days Transabdominal B mode US from 30 days Abdominal palpation from 60-70 days (not recommended)

6.6. Sow

6.6.1. Non return 18-22 days (stands firm when pressure applied to pelvis) Plasma prog. 16-24 days Transrectal B mode US 12 days Oestrone sulphate plasma 24-28 days Vaginal biopsy 18-22 days Rectal palpation 30 days (difficult) Transabdominal B mode 24 days A mode transabdominal US 30 days (works well) Transrectal Doppler US 25 days (not really done)