Feeding for Growth Flashcards
1
Q
DOD (developmental othopaedic disease
A
- issues arise as combination of multiple factors = causal componenets
- most issues require multiple components to interact
- Nutrition is one of those components in conditions such as DOD
~ Osteochondritis dissecans (OCD) = thickened articular cartilage and reduce blood supply to base layer of bone = causes cracking and flaking of bone which can break off or flap = inflammation of joint = lameness +/- arthritis
~ Epiphysitis = inflammation of the growth plate (physis), most commonly in fetlock joint
~ Bone cysts
~ Juvenile arthritis
~ Wobbler syndrome (Cervical Vertebrae Stenotic Myelopathy - CVSM) - other components = genetics, exercise, hormones, growth, conformation
- rapid growth associated with DOD, want to grow slowly = grow for profit but lead to skeletal issues, hard to sale
2
Q
what is common to all DOD
A
= rapid growth
~ Genetic disposition, conformation and environment increase risk
- DODs occur due to abnormalities of endochondral ossification (replacement of cartilage within bone) of the epiphyseal growth plates = dont grow properly
~ Alterations in bone mineralisation
~ Cartilage becomes thickened
~ Blood supply altered
~ Inflammation / necrosis of the tissues
- rapid and varied growth rates predispose to DOD
3
Q
nutrition impact on DOD
A
- High energy diets are most commonly associated with DODs, not excess protein
- Research is conflicting – high starch and fat diets
- One theory is high circulating insulin may affect chondrocyte maturation
~ Chondrocytes = cartilage cells which forma matrix. - Alters matrix and cartilage growth, and mineralisation of bones
- Nutrition of broodmare how lead to decreased insulin sensitivity = could be due to that rather than what foal is being fed
- Rapid growth leads to skeleton growing more rapidly than other nutrients are able to match
- Affected youngsters should have energy supply reduced whilst maintaining all other nutrients
4
Q
mineral imbalances and DOD
A
- mineral imbalences associated with DOD
- need to ensure correct ratio given
~ Ca:P = 2:1 (range 1.5:1 and 2.5:1)
~ Cu:Zn = 1.3 to 1.4 - Feed fortified feed or vitamin and mineral supplement or a balancer
- Weigh and condition score foal/youngster regularly
- Movement is needed for normal musculoskeletal development
5
Q
When do nutrients and energy requirements increase
A
- DE – month 5 onwards
- CP – month 5 onwards
- Vitamins A & E – raised throughout pregnancy
- Ca & P – small ↑ months 7-8, larger ↑ months 9-11
- Cu & I – months 9-11
- Fe, Mn, Zn, Se – no increases
6
Q
When does most of placental and foetal growth occur
A
- 80% of placental growth first third of preg
- 80% foetal growth and wt gain in final third of preg
7
Q
pre birth nutrition
A
- Nutrition of the foal begins before birth, making nutrition of the mare a priority
- Early pregnancy placental growth takes place
- Final 3-4 months of pregnancy the majority of foetal weight gain takes place
8
Q
What do you need to monitor
A
- BW and BCS
- most broodmares managed on pasture to satisfy DE/CP requirements but need vit/mineral source to meet maintenance requirements
~ as preg develops = add conc feeds fortified with vit/min or balancer which provides vit/min
~ Excess fat stores increase demand on joints and body systems and may increase difficulty with labour
~ Inadequate fat stores due to inadequate DEI to support foetal growth and maintain mare = mare utilising internal energy stores to support foetal growth
~ In late pregnancy vDMI may reduce due to less capacity in the GIT due to foetal growth = increase energy density of feed
9
Q
Under nutrition of mare
A
- Moderate (80% of DE requirement) – no effect in utero or post-natal growth of foal
~ Placenta adapts to compensate = vascularisation and changes in amino acid and vitamin metabolism - Severe energy deficit affects in utero growth of foal and reduces birthweight
- following effects are reported compared to foals born to mares receiving adequate energy
~ Delayed testicular maturation at 12 months old
~ Decrease in insulin sensitivity at 19 months old
~ Decrease in cannon bone width at 19-24 months old
10
Q
Over nutrition of mare
A
- Less clear understanding of effects of excess energy
- Obesity during early gestation has strong effects on embryo development due to changes in the uterus
Increased inflammatory markers and influence on lipid regulation - Obesity in dams did not affect foal birthweight but the following effects reported compared to foals born to mares receiving appropriate energy
~ Increased systemic inflammation in foals until 6 months old
~ Decrease in insulin sensitivity at 6 and 18 months old (more likely insulin resistant)
~ Increase in development of osteochondrosis lesions
11
Q
growth rate and influencing factors
A
- growth = increase in size
- optimum growth = increase in size of the horse from birth that allows for maximum health and performance at designated stage of life
- influenced by:
~ Genetics – growth pattern and overall size and shape of horse
~ Environment – nutrients available, climate, competition for food (short term)
~ Nutrition – impacts on genetically determined long-term growth pattern (short term) - most foals managed outside = season impacts nutrients and weather conditions
- once weaned, compertition with field mates can influence feed intake (dominant more, submissive less)
12
Q
how does growth occur and measures of growth
A
- Growth occurs through increases in the size of cells and the number of cells
- Differences in size between mature horses due to differences in the total number of cells
- Growth rate decreases as horses approach maturity, mainly due to decrease in cell proliferation (cell division)
- Horses classed as mature when 5-6 years
~ BW
~ Wither height
~ Body length
~ Metacarpal circumference
13
Q
what causes variability in growth rates
A
= range of breeds and sizes
- no breed standards = standard growth curves challenging
- Gro-Trac software tracking growth of TB foals accross world = allows comparisons
- classed as rapid moderate or slow
- subjective = diff management systems, enviro etc
~ 2 month old rapid = 1.2kg ADG, moderate = 1.0kg ADG
~ 6 month old = 0.9kg ADG rapid, 0.8kg ADG moderate
~ ADG reduces as get older
- body wt overall perameter but no account of differences in tissue development
~ bone then muscle then fat
14
Q
nutrition of foal
A
- The diet of the growing horse comprises of
~ colostrum,
~ milk,
~ water,
~ forage
~ concentrated feeds - The proportion of each component changes with the horses age and its circumstances
- Diet still needs to provide all of the nutrient groups
CHOs, proteins, fats, vitamins, minerals and energy
15
Q
Energy requirments
A
- Energy is the first limiting factor influencing growth rate
- Excess energy only optimises growth rate to its genetic potential
- Need other nutrients to be supplied in adequate quantities
- Energy above requirements = stored as fat and is associated with developmental issues
- Continue to calculate energy requirements using DEm plus DEg
~ Most accurate for 0-18 months of age, can be used up to 24 months old - When very young the proportion of the DE required for growth reduces as growth rate slows
- Initially energy provided by milk, then pasture/forage intake increases
~ Energy provided from VFAs - Upon weaning VFAs should provide majority of energy
~ Some also from concentrates - research shows TB foals fed fibre based feed at weaning had similar growth rates to foals fed cereal-based stud feed
~ Also supported GIT health compared to cereal-based feed
(Moore-Colyer et al. (2020))
