Animal Nutrition Exam 3

These flashcards cover key concepts in animal nutrition, reproductive physiology, lactation cycles, and poultry management

Least Cost Ration

A diet that meets the animals needs at the lowest cost

Why is there no perfect ration?

Producers balance for a group of animals, not one specifically. Animals have varying nutritional needs, digestive efficiencies, and environmental influences that prevent a single ration from being ideal in all circumstances.

Cost of factors that need to be considered within the least cost calculation

Cost of the feed, transportation costs, processing costs, and labor

NRC and why they are important

National Research Council; important for providing guidelines on nutrient requirements and animal husbandry practices.

Energy Units

Different measures for energy found in feed

TDN

Total digestible energy, does not consider diet related energy losses in urine, methane, and heat

DE

Digestible energy, the energy requirement of horses is generally expressed in terms of DE

ME

Metabolizable energy, energy requirements of pigs and poultry are expressed in terms of ME, takes into account losses due to urine and methane

NE

Net energy, the common energy unit in ruminants

Protein Requirements for Ruminants

Higher than non-ruminants due to their complex digestive systems needing specific types of amino acids.

Types of proteins for ruminants

Degradable intake protein (DIP) and undegradable intake protein (UIP)

Maintenance Concept

The minimum amount of energy required to keep an animal alive without growth or reproduction, where energy consumed is equal to energy used

First major component of maintenance

Basal metabolism

Basal Metabolism

The minimum amount of energy required to maintain vital functions in an animal when at rest, amount of heat generated by the body when at rest

Basal metabolic rate (BMR)

The lowest rate obtained while an animal is at complete physical and mental rest, measured by direct or indirect calorimetry

Factors influencing BMR

Body size, species, age, previous level of nutrition, climate

Muscular Work

The energy expenditure involved in movement, which is related to maintenance and overall energy requirements, ex. beating heart

Temperature regulation and maintenance

The colder it is the more energy an animal needs to be at maintenance, producing heat to keep the body warm takes energy

Key indicators for optimal reproduction

Ease of conception, a low rate of fetal and neonatal death, normal parturition, maximum litter size, adequate lactation, optimal rate of growth of healthy offspring

Puberty in Animals

The age at which an animal becomes capable of reproduction; can be influenced by breed, nutrition, and environmental factors.

Average age of puberty in cows

7 to 8 months (range of 4 to 18 months)

Average age of puberty in mares (horses)

10 to 12 months (range of 10 to 24 months)

Average age of puberty in ewes (sheep)

9 months (range of 5 to 12 months)

Average age of puberty in sows (pigs)

5 to 7 months (range of 4 to 9 months)

Breeding Assessment

The process of evaluating both younger and mature animals for their suitability for reproduction, needs to be in good health, up to date of vaccines, have an ideal body weight

Flushing

The practice of increasing the nutrient intake of breeding females prior to breeding to improve fertility.

Animals flushing is used on

Breeds or industries where litters are more desirable, works best on animals that have a poor body condition than ones that have a good condition

Ways to assess pregnancy

Abdominal and uterine palpations, ultrasound, radiographs (typically used after ultrasounds)

Gestation length of cows

9 months

Gestation length of ewe (sheep) and doe (goats)

145 to 150 days (5 months)

Gestation length of sow (pig)

3 months, 3 weeks, and 3 days (114-115 days)

Gestation length of mare (horse)

11 months

General nutrient requirements during early and mid-pregnancy (first and second trimester)

Nutrient requirements are relatively small, usually fed at or slightly above maintenance, care must be taken to not underfeed or overfeed (females are efficient at depositing fat at this time)

General nutrient requirements during late pregnancy (third trimester)

Nutrient requirements increase rapidly, energy needs increase 10-12%, calcium and phosphorus are needed at greater amounts to support fetal skeletal development

Maternal vs fetal body weight of sheep

13.3%

Maternal vs fetal body weight of cows

7.5%

Maternal vs fetal body weight of pigs

6%

Key Nutritional Factors during Pregnancy

Critical elements such as energy, protein, vitamins, and minerals essential for fetal development.

Heat Increment (HI)

The additional energy expenditure from feeding and digestion which can affect nutrient availability during pregnancy.

Three main sources of heat increment of pregnancy

Fetal metabolism, uterine and placental metabolism, non uterine tissues

Effects of Malnourishment

Negative impacts on both maternal and fetal health and development due to inadequate nutrition.

Lactation Cycle

The period of milk production in dairy cows, affected by various nutritional requirements.

Dry period

When the cow is no longer in the lactating herd but in her third trimester, 60 day period before the cow gives birth

Milk yield and % fat and protein

The higher the milk yield the lower the % of fat and protein

First lactation and feed intake

The cows need for energy is increasing and her appetite is decreasing, cow can not eat enough to meet demands for milk production and uses body tissue to make up for deficit, negative energy balance

First lactation nutrient requirements

Meeting the cows energy requirements, an increased number of concentrates is added to the diet, the replacement of forage with grain also decreases gut fill and the rate of feed removal increases

Second and third lactation nutrient requirements

Should be fed a ration that matches their production potential, milk production has declined so the cow is eating to meet demands of her productivity, she is usually pregnant at this time so there is still need for high energy

Dry period nutrition requirements

Cow is fed a higher energy diet, grains are fed, requirements are also increased from year 1 to 2 to 3 because the cow is gaining body weight so she needs more nutrients for maintenance

Dairy vs meat calf

Dairy calves are separated from the mother at birth, meat calves are separated when they are weaned

Calf nutrition requirements

Colostrum soon after birth, then milk until it is weaned around 5 to 8 weeks, since a calf functions as a non-ruminant it must be fed easily digested carbohydrates, proteins, and lipids to meet nutrient requirements

Heifer nutrition

Should be fed a diet consisting of forage, additional concentrates, and protein for growth

Body Condition Score (BCS)

A measure using a 5 to 9 point scale to assess the fatness of dairy cattle, influencing reproductive success.

Metabolic Diseases

Health issues arising from incorrect nutrition, such as bloat and acidosis.

What condition can occur if blood glucose drops too low?

Ketosis

Milk Fever

A condition caused by low blood calcium levels, often occurring around calving.

Milk Fat Depression

A decrease in milk fat content often linked with diet changes, particularly in lactating cows.

Somatotropin (bST)

A hormone used to increase milk production, causes more nutrients being eaten to be used for production, cows using this increase feed intake, considered controversial due to animal welfare concerns.

What is meant by the term growth and what happens during this time period?

Includes many phases of life, a continuous and dynamic process

Colostrum

The first milk produced by a cow after giving birth, rich in antibodies, minerals, total solids, and high concentrations of protein and fat which is essential for newborn immunity.

Newborn Care

Dam should be provided with a clean, dry, well ventilated environment to give birth and decrease the newborn’s exposure to disease and pathogens, temperature of this area should be monitored and controlled since newborn’s can’t regulate their body themperature

Digestive tract of a newborn

High lactase activity, little pepsin activity (protein digestion is low) to help prevent the breakdown of immunoglobulins, born with spaces between the intestinal epithelium cells that allow the large immunoglobulin protein molecules to cross through and enter the blood (closes around 35 hours old)

Unique features of newborn ruminants’ digestive system

Esophageal groove allows milk to go straight into the abomasum and bypass the rumen

Management of the newborn

Humans may assist in removing fetal membranes, drying the animal, cutting the umbilical cord, makes sure the newborn receives colostrum

Process of a newborn piglet

Given a shot of iron to prevent anemia because the sow’s milk is iron deficient

Process of newborn ruminants’

Injected with vitamin A and may also receive vitamin E, D, and iron

Milk replacer

Used when a newborn cannot be raised by its dam

Weaning Process

The gradual transition from milk to solid food which is crucial for growth, usually begins 2 weeks after birth

Creep Feed

A method of supplementing the diet of young livestock by offering solid feed to animals who are still nursing, very palatable, helps prepare the animals digestive tract for weaning  

Postnatal Growth Definition

The growth that occurs after birth as the animal transitions to independent feeding.

Allometric Growth

When different parts of an animal grow at different rates and times

Body Composition Measurement

Methods to assess body fat and lean mass, including direct and indirect techniques.

Direct measurements of body composition

Whole body dissection (all tissues and organs are removed and weighed), chemical composition of the animal (analyzing the amount of water, protein, fat, and ash)

Indirect measurements of body composition

Most common way to assess body composition, can be repeated, ultrasound, back fat probe, live weight, visual assessment and subjective evaluation,

Four factors influencing body composition

Age, genotype, sex, nutrition

Age influencing body composition

Body weight increases as animal gets older, young animals tend to be high in protein, older animals tend to be high in fat

Genotype influencing body composition

Determines what its mature body size is and what its physiological maturity and body composition will be at a given weight

Sex influencing body composition

Males tend to be leaner than females, castrated males tend to fall between males and females

Nutrition influencing body composition

Affected by both protein and energy intake, when the body has extra energy it deposits it as fat

Beef Cow Lifecycle

Maintained primarily on pasture, produce one calf per year, re-bred within 60 to 90 days after giving birth, calves nurse for about 7 months, calves are born in spring or fall

Nutrition Guidelines and recommendations for cows postpartum

The period of greatest nutritional demand, fresh forage always available, grain supplement for energy if needed, mineral supplement for grazing cattle

Nutrition Guidelines and recommendations for cows lactating and pregnant

Nutritional requirements are high but energy requirements decrease, will lose some weight during this period

Nutrition Guidelines and recommendations for cows at gestation

Nutritional requirements are at its lowest, cows voluntary feed intake is at its lowest but its the best time for cows the put-on weight and increase body condition score

Nutrition Guidelines and recommendations for cow pre-calving 

The most critical period for the cow to have a good body condition score, energy and protein needs increase by 20% compared to gestation

Nutrition Guidelines and recommendations for a weaned bovine (meat cow)

Animal is about 30% fat, fed a high grain diet to gain weight as quickly as possible, rumen acidosis is common

Nutrition Guidelines and recommendations for bulls

Needs good quality pasture but about 15% more than a mature cow, younger bulls need increased grain and crude protein to attain a good body condition score for breeding

Most common type of bloat

Feedlot bloat

Why feedlot bloat occurs

Results from foam in the rumen that stops the animal from expelling gas, the foam can cover the cardia and prevents animal from belching

Clinical signs of bloat

Swell rapidly on left side, may show signs of discomfort like kicking their side or stomping their feet

Treatment for bloat

Poloxalene can be administered through a stomach tube with the guidance of a vet, feed coarsely chopped roughage as 10 to 15% of the ration in a finishing diet, or a bloat needle or trocar can be used in extreme cases to puncture the rumen wall on the left side of the animal

Why rumen acidosis occurs

The result of low rumen pH, associated with a shift from a forage-based diet to a high concentrate-based diet

Clinical signs of acidosis

Diarrhea, dehydration, cattle can appear weak, anorexic, and uncoordinated, manure is soft, gray, and foamy

Why grass tetany occurs

When magnesium and calcium levels in forages are too low to meet requirements 

Clinical signs of grass tetany

Nervousness, muscle twitching, and staggering while walking. An affected animal may go down on its side, experience muscle spasms and convulsions, and even death

Treatment of grass tetany

Early treatment is important, blood magnesium levels can be increased within 15 minutes by IV or 500 ml of calcium borogluconate solution with 5% magnesium hypophosphate

Poultry Nutrient Requirements

Specific dietary needs for chickens and turkeys, including proteins and carbohydrates.

Energy in poultry feed intake

Birds will stop eating when their energy requirement is met regardless of the other requirements, diets are based on metabolizable energy (ME)

Protein in poultry feed intake

As a bird grows the need for protein declines,

Common poultry feeds

Most are fed corn (for energy) and soybean meal (for protein), hydrolyzed feather meal

Common feed additives

Coccidiostats and antioxidants

Growth Differences egg layers and broilers

Broilers grow very fast and very quick, egg layers grow slower over time