Quiz 5: Nutritive Value of Feedstuffs; Growth and Development; Reproduction
Factors Influencing Digestibility
*fiber content*, rates of passage, preparation and processing - will vary by animal
Relative Protein Values
- Eggs: 100 - Milk: 92 - Meat: 82 - Rumen Protein: 80 - Plants: variable
Vas deferens
- carries sperm cells and substances from the epididymus to the urethra - some species have enlarged portion called the ampulla (@ end)
Chemical Analysis - Van Soest
- has breakdown of fiber 1) Acid Detergent Fiber (ADF): contains cellulose and lignin; usually associated with digestibility 2) Neutral Detergent Fiber (NDF): contains cellulose, hemicellulose, & lignin; may contain intake (amt. animal may consume) * always higher because contains more components
Reproduction 4 stages
1) Gamete production: production of egg and sperm 2) Gamete maturation: ability to be functional 3) embryo development: after fertilization, growth of embryo 4) delivery: young animal leaves mother.
Controlling Mechanisms - short-term mechanisms
1) Monogastric animals a) gut-fill (physical) b) glucose (chemical) 2) Ruminant animals a) gut-fill (physical) b) VFA's (chemical)
Chemical Analysis - proximate
1) Water: determined by drying sample 2) Ether extract (EE): measures crude fat; most concentrated form of energy. 3) crude fiber - contains cellulose, lignin, and most hemicellulose 4) crude protein = N x 6.25 5) Ash: minerals 6) Nitrogen-free extract (NFE): obtained mathematically; mainly sugars & starches (some hemicellulose)
Prenatal stage
1) blastocyst - occurs after fertilization; nutrition is from uterine secretions and egg itself. 2) embryonic - cell differentiation into tissues and organs; very small increase in weight 3) fetal - major growth in weight and composition; nutrition is from maternal blood stream through placenta
Controlling Mechanisms - hypothalamus involvement
1) feeding center (appetite) - eat 2) satiety center - stop eating
Priority system for use of nutrients
1) nervous tissue, vital organs 2) skeletal 3) muscle 4) fat 5) reproduction (in preg. female - will take priority #2)
Factors that limit growth (postnatal)
1) nutrition 2) disease(s) 3) parasite(s)
TDN is determined by
1) proximate analysis 2) digestion trial 3) multiplying 1 and 2 together
Four phases post natal growth
1) short time after birth - head, neck, and legs - type of tissue: bone, muscle, and vital organs 2) early growth - body increases in length - type of tissue: bone, muscle, and vital organs 3) middle growth - increase in depth and width of body - type of tissue: bone, muscle, fat 4) late growth - additional development and width of body - development of loin and hind quarters - type of tissue: muscle, fat
Steps involved in determining nutritive value
1. Chemical Analysis 2. Palatability 3. Digestibility
energy deficiency
1. decrease in body weight 2 decrease in body fat emaciation 3. decrease in fertility 4. decrease in production
Growth curve post natal - a summation
1. different organs and tissues grow at different rates 2. different organs and tissues grow at different times 3. distribution of body parts and body comp. changes during life of animal (fat goes up, muscle goes down)
Scrotum functions
1. house and protect testicles 2. regulate body temperature of testicles (3-13 F) lower than body temp
Factors affecting compensatory growth
1. how severe is the nutrient restriction 2. how long did it occur 3. what time in their life was restriction
Factors influencing feed intake
1. physiological state 2. weight 3. activity level 4. temperature 5. disease status 6. palatability
Accessory sex glands functions
1. secrete nutrients 2. secrete buffers 3. secrete substances to cleanse & lubricate urethra - volume of semen produced depends on size of glands.
Accessory sex glands
1. seminal vesicles (vesicular glands): two 2. prostate: one 3. bulbo-urethral glands (Cowper's): two
Factors influencing prenatal growth
1. size of dam/ size of sire (genetics) 2. number of fetuses 3. implantation site in uterus 4. nutrition level of dam 5. disease status of dam (others - gender/sex)
Mature animal generally speaking eats ____ of its body weight per day
2-3%
Fats (lipids) have ___ more energy per gram than carbs or proteins
2.25
Average Daily Gain
ADG (W2-W1)/(T2-T1)
TDN (total digestible nutrients)
An estimate of energy content in feed - it really doesn't measure digestion
Protein Sources
Animal Sources - fish meal, meat scraps, meat and bone meal, blood meal Plant Sources - soybeans, cottonseed meal, etc.
Order of peaks in differential growth of major tissues graph
CNS (vital organs), Skeleton (bone), muscle, adipose (fat)
Energy - units
Calorie, Kilocalorie, Megacalorie
Calculation of Apparent Digestion Coefficient (ADC)
D/C = (Weight of Nutrient Consumed - Weight of Nutrient Excreted in Feces)/ Weight of Nutrient Consumed
Biological Partitioning - Digestible Energy
DE = GE - FE
Sometimes females won't go into heat. Why?
Energy is used for nervous tissue, vital organs, skeletal, muscle tissue, and fat
Biological Partitioning - Gross Energy
GE: total amount of energy - always largest
What sets the maximum mature size and rate of growth?
Genetics. All other factors determine the proportion of maximum that will be obtained.
Monogastrics (average quantities and kinds of feed)
Grains, concentrates 2-6% of BW/day very young could be up to 13%
Biological Partitioning - Metabolizable Energy
ME = GE - FE - UE - GPDE * energy available for use in cells used to calculate birds energy. can't differentiate between UE and FE because cloaca mixes them
Biological Partitioning - Net Energy
NE = GE - FE - UE - GPDE - HI * always smallest * available energy for maintenance, growth, and lactation (accounts for energy used in consumption and digestion of foods)
Growth velocity curve, what is the peak?
Puberty
Ruminants (average quantities and kinds of feed)
Roughages 1-3%. of BW/day ** probably 2-3%
Postnatal stage
Shape - sigmoid a) self-accelerating: initial exponential phase of growth b) self-inhibiting: growth slows because of restraints
Chemical Analysis - NIR (Near-Infrared Spectroscopy)
Spectroscopy - rapid method using infrared lights to analyze bonds in feeds and determine moisture, fat, protein etc.
Measurements of growth and development
Weight, height, length, body composition
Compensatory growth
a period of accelerated growth that follows a time of nutrient restriction
Epididymis sections
a) Head (top of testicle) b) Body c) Tail (bottom of testicle)
Protein Quality
a) chemical procedures: amino acid analysis b) biological procedures: biological value (BV) - BV = N retained/N digested x 100 c) relative protein values d) protein sources
Testicles - Types of tissue and function
a) interstitial: cells of Leydig produce testosterone which gives male characteristics (ex. antlers on deer, crested neck of bull) - interstitial is between seminiferous tubules b) seminiferous tubules: spermatogenesis occurs, tubes are very long 1/2 to 1 mile uncoiled
Influences of sex hormones
a) mature size: M>F b) rate of growth: M>CM>F c) rate of fattening: - cattle & sheep F>CM>M - swine CM>F>M d) feed efficiency: M>CM>F e) Carcass Characteristics - lean: M>CM,F (testosterone effect) - fat: F,CM>M
Factors influencing energy requirements
a) species b) age c) activity level d) production levels e) temp (environmental) f) nutritional deficiencies h) surface area of animal
Semen composition
a) spermatozoa b) secretions - quantity and concentration varies by species - accessory sex glands - vas deferens - epididymus * higher volumes of semen have lower concentrations of sperm per mL of ejaculatory fluids
epididymus functions
a) storage of sperm cells b) provision of maturation space of sperm cells b) nutrition of sperm cells through secreted substances
Avian male differences in reproductive structures
a) testicles - same b) epididymus - same c) vas deferens - conducts semen into cloaca area.
factors encouraging growth: Genetic Hormones - growth of specific organs
a) thyrotropin (TSH): from anterior pituitary, targets thyroid b) adrenocorticotropic (ACTH): targets adrenal cortex c) gonadotropins: targets gonads 1) follicle stimulating hormone (FSH) 2) luteinizing hormone (LH)
factors encouraging growth: Genetic hormones - permissive for growth
a) thyroxin - from thyroid, sets metabolic rate b) insulin - from pancreas; promotes cell division c) adrenal corticoids: from adrenal glands
Protein Quantity
a) total protein b) digestible protein
Tumors
abnormal localized cell growth without normal control mechanisms
Regulating feed intake
animals eat to meet energy requirements - see diagram pg. 92
Lipostatic theory
appetite is regulated by fat reserves - applies to hibernating animals
Atrophy
cells start to shrink
Testicles - location and migration
descend through inguinal canal to the scrotum around time of birth **chicken = exception
Appetite
desire to eat
Chemical Analysis - complete
done in lab; looking at every amino acid, mineral etc.
Consequences of having to much protein
expensive, growth is good, excess H2O intake
Vitamins
expressed as international units (IU's - fat soluble), mg, etc.
Minerals
expressed as ppm, % mg, etc - macrominerals in animal carcasses at greater than 100ppm
Leptin control of appetite
from adipose (fat) tissue * decreases appetite
Neuropeptide Y (NPY) control of appetite
from hypothalamus * increases appetite
Cryptorchidism can be
genetically transmitted
Somatotropin
growth hormone from pituitary - increase cell growth, mitosis, and protein production and stimulates bone growth (growth plate)
Glucocorticoids
help regulate carbohydrate conversions + metabolism
Hyperplasia
increase in cell numbers (early, prenatal stage)
Hypertrophy
increase in cell size (after birth)
CCK control of appetite
influences hypothalamus * decreases appetite
Satiety
lack of desire to eat
Concentrates
less than 18% crude fiber
Consequences of having to little protein
lower growth, decreased efficiency
Roughages
more than 18% crude fiber
Bomb Calorimeter
obtains gross energy (GE) of feed
Passageway for urine and sperm
penis is the origin of copulation for males. Urethra is a large canal in the penis
mineralocorticoids
regulate concentrations of minerals especially Na + K
Byproduct feeds
result from manufacturing process ex. distiller's grains (alcohol product), brewer's grains (beer product)
sigmoid flexure
retractable muscle controlled presentation of the penis. Seen in pigs sheep cattle and goats. Bone = dog
Variations in semen (avian male) compared to mammals
semen is more concentrated and has a lower volume than mammals (missing accessory glands)
Digestibility - definition
the ability of a nutrient to be digested and absorbed by the animal rather than be eliminated by the feces
Epididymis anatomical relationship to testicle
the head of the epididymus connects to the seminiferous tubules through efferent ductules
What are the limitations of complete, proximate, and NIR chemical analysis?
they do not tell about palatability, toxicity, or digestibility.
cryptorchidism
unilateral: one testicle does not descend through the inguinal canal bilateral: neither testicle descended from inguinal canal - definite reduction in testosterone levels - much lower fertility
Breeding Soundness Exam (BSE)
used to see if both testicles have descended