Ill Thrift in Lambs Flashcards
what are lamb diseases in preweaning period
nematodirosis
coccidiosis
parasitic gastroenteritis
ruminal acidosis
pulpy kidney
what are lamb diseases in post weaning period
parasitic gastroenteritis
pneumonia
ruminal acidosis
pulpy kidney
why is lamb growth important
Reduce housing pressure
Increase grass for ewes
Environmental pressure
Reduce feed costs
Reduce worm/fluke issues
Reduce losses (pneumonia/pulpy kidney)
Lamb price at market
Price at slaughter
Meat quality
what are pre weaning target growth rates
300g/day
hill: 240g/day
what are possible pre weaning growth rates in pre weaning
500g/day
what gives max growth rate in pre weaning period
single male with milky mother
what is target post weaning growth rate
200g/day
what is possible growth rate in post weaning period
350g/day
what gives max growth in post weaning period
clover and grass at optimal sward height in rotational paddock system
what influence the birth weight
genetics of dam and sire
ewe nutrition during preg
Weighing all lambs at birth can be useful but not all farms have the capacity
But even 10-20% of lambs will help give variation between years
what influences 8 week weight
20kg
ewe management
ewe performance (selection?)
what influences weaning weight
what influences fortnightly post weaning
nutrition (appropriate/deficiencies)
presence of disease
what influences good milk production
what should the DMI be for lambs
2.5-3.5% BW
what should ewe milk yield be
1L/lamb early lactation
down to less than 500ml/lamb later in lactation
what can delay weaning
good grass: enough for lambs as well as ewes
what weight can help with selection of ewes and is an important indicator for later productivity of lambs
8 week weight
how do you compare pre and post weaning DLWG
If it decreases - some decrease is expected in the short term but it should not be excessive or prolonged
If it increases – was weaning too late? Meaning that the ewes were competing with the lambs for the best grazing
Or are there trace element deficiencies that are masked before weaning
what should lambs ideally weigh at weaning
over 25kg
min 16kg
what DLWG shoud lambs be weaned at
<200g/day
what are potential problems with inadequate nutrition
poor milk production (maternal undernutrition, maternal disease, maternal genetics)
excessive stocking rates
poor quality pasture
inadequate grass length (ideal 5-8cm)
how much trough space do lambs need
30cm/lamb
how much lying space do lambs need
0.9m^2
what is the role of protein, CHO after weaning
protein: frame
CHO: fat
what % of grass is utilized in paddock, small field and set stocking
paddock: 80%
small field: 65%
set stocking: 50%
what are inhibitors of growth
Parasitic gastroenteritis
Mineral deficiencies
Liver fluke
Lameness
Nematodirosis
Coccidiosis
Pneumonia
Orf
Navel ill
Joint ill
Poor nutrition
when does coccidiosis occur
spring/summer
what are the coccidiosis species
Eimeria crandalis
Eimeria ovinoidalis
Eimeria bakuensis
why is coccidiosis difficult to diagnose
Coccidiosis and Nematodirosis have similar timing and clinical signs, so can be difficult to differentiate in lambs with diarrhoea
Concurrent infection of pathogenic Eimeria and Nematodirus battus is possible and the clinical signs are more severe than for either disease alone
what are the risk factors for coccidiosis
3-8 weeks old
Post weaning in naive animals
Youngest lambs
Indoors; wet, dirty conditions
Short grass
Areas that lambs congregate
what is the PPP of coccidiosis
2-3 weeks
how long can sporulated oocysts survive
over 1 year
how are coccidiosis oocytes destroyed
UV
heat
dessication
what are clinical signs in acute disease of coccidiosis
Diarrhea, dark, mucoid, +/- blood tinged
Dehydration (normally cause of death)
Death
what is the clinical signs of chronic coccidiosis disease
Chronic ill thrift/poor growth rates
Chronic, subclinical infection OR permanent GIT damage after acute infection
how is coccidiosis diagnosed
History of intestine lamb management
Clinical signs
- Often coincide with start of oocyst shedding unless heavy infections, in which case signs can be seen earlier
Fecal oocyte count
PM
Response to treatment
how does fecal oocyst count diagnose coccidiosis
Fecal oocyst count >10-50,000
how can coccidiosis be diagnosed on PM
Hemorrhagic small intestines +/- cecum and colon
Histology or SI smear
Merozoites in smears from gut walls of freshly dead animals
Histopathology of guts from freshly dead animals
Samples have to be taken within 20mins of death because of the rapid autolysis of the intestinal mucosa
how is coccidiosis treated generally
Symptomatic treatment
Dehydration is most common cause of death
how is acute coccidiosis treated
Fluid therapy
Oral in most cases unless valuable lamb
Nutritional support may be needed if there is prolonged diarrhea and anorexia
Coccidiocidals
- Need to dose during the pre-patent period with both if possible, 14 days after moving to high risk pasture
- Diclazuril (Vecoxan) twice
- Diclazuril is thought to only treat the later stages of the Eimeria spp, so needs to be repeated
- Toltrazuril (Baycox) once
- Treats all stages of infection, so only needs to be given once
- Has more prolonged impact on DLWG and oocyst shedding in lambs
Anti inflammatories
Can help reduce the impact of the infection on the GIT
Reduce exposure
how is coccidiosis prevented
Avoidance is highly recommended and pharmaceutical products should only be used where they are unavoidable
Muck out sheds regularly
Avoid dampness in sheds
Rotate grazing
Keep later born lambs in different sheds/ on different pasture
Reducing stocking densities to reduce contamination
Maintaining good pasture height to avoid grazing too close to the ground
how pharamceuticals can be used to prevent coccidiosis
In feed treatment with the coccidiostatic, decoquinate, can be used in ewes prior to and after parturition.
Or it can be used for lambs, although because it is a coccidiostat, it is necessary to use it for a minimum of 28 days, otherwise development of the cocci stages will recommence and disease will only have been delayed
The coccidiocidal drenches used to treat lambs can also be used pre-emptively to prevent disease if the timing of exposure is known (e.g. when lambs were moved to a contaminated pasture)
what pharmaceuticals are used to treat coccidiosis
what does cobalt defiency in lambs cause
Epiphora
Poor growth rates
Unkempt fleece
Diarrhea
Anemia
Hepatic encephalopathy — associated with fatty liver (ovine white liver disease)
(Weak lambs)
what does selenium defiency in lambs cause
poor growth rates
poor fertility in ewes, neonatal disease
can be toxic
what does copper defiency cause in pregnant ewes
Reduced milk production
High perinatal lamb mortality
- Weaker lambs with reduced vigour that are slower to get up and suckle colostrum —> higher mortality rates
what is the function of cobalt
Incorporated into vit B12 by microflora in ruminoreticulum, released from microflora in abomasum and absorbed in small intestine
Gluconeogenesis from propionic acid (in liver)
Lack of utilization of propionic acid results in reduced appetite, hence clinical inappetance and ill thrift
what are risk factors for cobalt deficiency
Varies between years
Soil type, iron-rich, alkaline, and manganese-rich soils
Soil impaction
Fast growing pasture
- Improved pasture
- Spring/summer
Well drained soils/dry pasture — summer
Low pasture clover content
how is cobalt deficiency diagnosed
- clinical signs, grazing history and geographic location
- dose response trial
- serum vit b12
- liver vit b12
- soil cobalt
- pasture cobalt
- raised blood/urine MMA (methylmalonic acid)
how is cobalt deficiency treated
Clinical disease associated with deficiencies requires injectable vitamin B12 in the first instance, to promote increased appetite in the lambs
Then other sources of supplementation can be provided
how is cobalt deficiency prevented (6)
- cobalt salts (Co sulphate)
- anthelmintic, Co, Se drenches
- free access minerals
- intraruminal boluses (short or long term)
- minerals in compound feed
- pasture dressing in late spring (liquid or solid)
what does selenium deficiency in adult sheep
reduced fertility, ewes and rams = fewer ewes in lamb
what does selenium deficiency cause in pregnant ewes
causes weak lambs, white muscle disease
what does selenium deficiency cause in growing lambs
- ill thrift
- impaired immune function
what is the function of selenium (2)
- protects cell against reactive oxygen metabolites (ROM)
- complimentary role with vitamin E
where are the most reactive oxygen metabolites (ROM)
skeletal, respiratory and cardiac muscles
white blood cells
what are the risk factors of selenium deficiency (5)
- low soil content – large areas of UK
- fast grass growth (spring)
- under supply of other anti oxidants, as vitamin E
- high dietary oxidants (spring grass, root crops)
- generation of oxidants (exercise, infection, toxemia)
how is selenium diagnosed (5)
- clinical signs, flock history/location, exclusion of other causes
- soil, pasture or animal testing
- serum glutathione peroxidase (GSHPx)
- serum and liver selenium ($$)
- WMD: creatinine kinase and post mortem
how is selenium deficiency treated
care overdosing can be toxic
- injections
- oral supplementation
what are selenium injections used to treat deficiency
Injection with selenium salts +/- vitamin E (1-3 months) — more expensive
Controlled release injections (9-12 months) — reduced risk of toxicity
how is selenium deficiency treated with oral supplementation
Oral selenium salts
Intraruminal boluses (short or long term, often multiple elements)
Top dressing pasture (12-24 months)
Minerals in compound feed
Free access blocks/buckets/powders
how is vitamin E deficiency diagnosed
plasma a-tocopherol
<1umol/L — high risk of WMD without Se deficiency
<2umol/L — high risk of WMD if Se also deficient
what type of forages are high in vitamin E
green pastures
low in root crops
decline when forages are dried and stored for long periods
how is vitamin E deficiency treated
injection with Se or oral supplementation
what are the signs of acute selenium toxicity
Toxic to cardiovascular system
Dyspnea
Recumbency
Diarrhea
Death
what are the signs of chronic selenium toxicity
seleniferous plants
Non-specific
Dullness
Ill-thrift
Anemia
Brittle hooves (sloughing in extreme cases)
what does iodine deficiency cause in adult sheep
Perinatal lamb mortality (can be high)
+/- goitre
Scant wool
Poor thermoregulation
Poor lamb vigour
what are the risk factors of iodine deficiency
Pasture or forage crops high in thiocyanate goitrogens
Late pregnancy
how is iodine deficiency diagnosed
Post mortem — thyroid weight:body weight
- >0.4g thyroid:1kg BW
Plasma inorganic iodine (PII)
- Contemporary iodine intake
- Good estimate of sufficiency, less for deficiency
how is iodine deficiency treated
Intramuscular injection of iodized oil pre-mating
Sustained release ruminal boluses — I, Se, Co
Oral dosing
- 280mg potassium iodide 8 and 4 weeks before lambing
how is iodine deficiency treated with oral supplementation
Reduced IgG uptake by neonatal lamb
Beware of multiple supplements used:
- Concentrate feed minerals
- Intraruminal boluses
- Oral drenches
what does copper deficiency in lambs cause
sway back
ill thrift (not consistent)
lamb osteoporosis + fractures
tendon abnormalities – stiffness
depigmentation
steely wool
anemia
what are the risk factors for swayback
Severe copper deficiency in mid- to late pregnancy
Mild winters — less supplementary feeding
Improved pasture (raised pH can make Mo more available)
Spring (higher Mo levels)
Soil (+ iron) intake in wet conditions (reduces SI copper absorption)
Breed
Scottish Blackface
High fibre diets
what are the clinical signs of swayback
Swayback is either noted immediately after birth, with the congenital form, or at 2-4months of age after a stressful event
Hindlimb weakness results in a swaying, stumbling gait, along with other signs of neurological deficiency, secondary to demyelination of the nerve fibres
what are the two forms of swayback
congenital
delayed form (enzootic ataxia)
what are the clinical signs of congenital swayback
Small, weak lambs
Fine head tremors
Less severe — bright, poor coordination, weakness in hindlimb
Fine boned, dull coated
what are the clinical signs of delayed form of swayback
Normal at birth, from 2-4 months of age
Hindlimb weakness results in a swaying, stumbling gait, along with other signs of neurological deficiency, secondary to demyelination of the nerve fibres
how is copper deficiency diagnosed
Clinical signs and flock/local history
Histopathology brain/spinal cord
Plasma or serum (10-20% lower) copper
liver copper (3 samples)
response to supplementation (care)
how is copper deficiency treated
congenital – hopeless
delayed may respond to supplementation
how can copper deficiency be prevented through injections
Lasts 2-4 months
Good mid pregnancy swayback prevention
Overdosing = severe toxicity
how can copper deficiency be prevented using oral supplements
- oral copper salt drenches
- boluses
- concentrate feed with minerals
- blocks/buckets/powders
- pasture top dressing
how are oral copper salt drenches used
4-8 weeks pre-lambing
Risk of toxicity limits dose
how are oral copper boluses used
Gelatine with copper oxide wire/needles
- The copper oxide wires have lower toxicity risk in deficient animals than other more quickly absorbed methods
- They are absorbed over 3 – 4 weeks and top up liver copper stores, wires stay in the abomasum during this time and dissolve in the low pH
- Not susceptible to molybdenum or Sulphur interference in the rumen, but they are susceptible to reduced absorption due to iron absorption with soil ingestion in wet conditions
Multi trace element boluses
- Multi-element boluses may not provide enough Cu in peak requirement times on deficient farms
how are concentrate feed minerals used to prevent copper deficiency
Include molybdenum to reduce available copper
how are blocks/buckets/powders used to prevent Cu deficiency
Copper levels low to avoid toxicity
how is pasture top dressing used to prevent Cu deficiency
Top-dressed pasture cannot be grazed by stock for 3 weeks after dressing, or after heavy rain
Unweaned lambs have very efficient Cu absorption so should not be grazed on recently top-dressed pasture
what breeds are especially sensitive to Cu toxicity
texel, suffolk, north ronaldsay
what are risk factors for copper toxicity
Multiple supplements (remember concentrates)
Unweaned lambs
Breed
what is seen on PM with Cu toxicity
Orange carcass
Gun-metal black kidneys
Black urine
what does acute Cu toxicity look like
Within 24 hours
Severe gastroenteritis
Colic signs and diarrhea
Collapse and death
what does chronic Cu toxicity look like
Acute hemolytic crisis
Jaundice
Anorexia
Diarrhea
how does chronic Cu toxicity occur
Results from low levels of over-supplementation over a long period, the liver stores (in lysosomal cells) the excess copper, then when it reaches capacity the copper is released into the circulation all at once and a haemolytic crisis and jaundice results, it is often seen as sudden death
when is Cu toxicity typically seen
Cu toxicity can occur after housing because sheep are not longer exposed to the iron in the soil which interferes with Cu uptake, and are likely to be fed concentrates
how does liver fluke affect growth rate before weaning
poor ewe body condition –> low lamb birth weights + low milk production
how does liver fluke affect growth rate after weaning
sudden death
liver damage
how does lameness affect poor growth rates before weaning
poor ewe condition –> low birth weight + poor milk production
how does lameness affect poor growth rates before and after weaning
lame lambs ==> poor growth rates
what are some other diseases that can cause poor growth
- dental disease
- resp disease
- ectoparasites
- neuro diseases
- plochter – bog asphodel
- ruminal acidosis
what ectoparasites can cause poor growth
Blowfly strike
Sheep soap (Psoroptes ovis)
Chewing lice (Bovicola ovis)
Sucking lice (Linognathus spp)
what neuro diseases can cause poor growth
CCN
Louping ill
Meningitis
Coenurosis (GID)
Sarcocystosis
Chronic lead poisoning
what are diseases that affect individuals
pneumonia
dental problems
what are diseases that affect small #s
blowfly strike
neonatal diseases
what are diseases that affect large #s
nutrition
TE deficiencies
liver fluke
sheep scab
haemonchus
how do you tell the longevity of the growth problem
well grown but thin = recent problem
small frame and thin = long term
small frame but well fleshed = historical, potentially resolved
