Energy for Reproduction

Question 1

Reproductive energy includes

Answer 1

• sperm
• eggs
• fetal development
• reproductive organs
• milk production
• heat for egg incubation
• territorial establishment and defense
• courtship
• nest/ burrow construction
• searching for and acquiring food for young

Question 2

Males- energy and nutrients demands

Answer 2

testicular growth - minimal energy and protein requirements

sperm production- minimal energy and protein requirements

Question 3

Female - energy and nutrient demands

Answer 3

ovary/oviduct growth- minimal energy and protein requirements

fetal development (gestation)
- DEE of gestating mammals = 2.9 xBMR

mammary gland development

milk production

• DEE of lactating animals is 5.5 x BMR
• milk produced by ALL mammals

Question 4

Colostrum

Answer 4

the first milk produced during each lactation

• typically rich in immunoglobulins
• provides passive immunity to the neonate

Question 5

Maternal immunity can be passed to the fetus:

Answer 5

only in utero- lagomorphs, primates

both in utero and from colostrum- rodents, felids (taurine is very high) , canids

only in colostrum: only for as long as the GIT is permeable to Ig absorption - ungulates ( ~36 hrs), marsupials (200 days)

Question 6

Milk

Answer 6

nutrient composition
- water, minerals, vitamins, protein, fat, carbs

dilute- less energy per meal= slower growth of young
concentrated- more energy per meal- faster growth of young

Question 7

Seals

Answer 7

fat, protein, energy concentration milk

• may compensate for rapid rates of heat loss (high fat deposition)
• accommodates extremely short lactations (4 days in hooded seals)
• may be adaptive for breeding/birthing on unstable ice pack (can quickly leave)

Question 8

Marsupial milk production

Answer 8

Period 1
- young are confined to pouch- food, warm, safe, dilute milk, relatively low [] of nutrients

period 2
- young can leave the pouch but will return to feed- more concentrated, higher nutrient []

Question 9

hiders (milk intake type)

Answer 9

mother returns to “hidden” neonate periodically to nurse

• young nurse infrequently, but drink lots each time
• milk typically more rich

Question 10

followers (milk intake type)

Answer 10

young follows mother around and is constantly eating a little bit

Question 11

Altricial species

Answer 11

young showed marked delay in becoming independent

young hatched/ born naked, blind, immobile
- robins, crows, owls, rats, mice, humans
cannot survive without parental care

Question 12

Precocial Species

Answer 12

young show high degree of independence from birth/hatch
young born/hatched with plumage/pelage, well-sighted, mobile
- chickens, ducks, deer, lagomorphs

Question 13

BIRDS- Egg production

Answer 13

nutrients demands depend on…
CLUTCH SIZE- varies with age, food availability
~younger females lay fewer eggs
~ fewer eggs laid when food is scarce

EGG SIZE- varies with age and food availability
~Inversely proportional to body weight
~ younger lay smaller eggs
~ smaller birds lay larger eggs relative to body weight

EGG COMPOSITION- varies with stage of development at hatching
~ yolk size is larger with precocial species (40% vs 20% for altricial species)

precocial birds tend to lay fewer, larger eggs than altricial species 1 precocial egg =150%of BMR
1 altricial egg = 30% BMR

Question 14

to meet energy /nutrient requirements for egg laying

Answer 14

fat deposition prior to egg laying
mobilizing body fat and protein (lean mass) when laying
increase food intake
diet shift to nutrient rich foods

Question 15

Incubation

Answer 15

maternal/paternal heat is needed to

• initiate embryonic development in the egg
• ensure development continues appropriately

Question 16

amount of heat required for incubation depends on…

Answer 16

clutch size
nest incubation
body weight of adult
ambient air temp
eventually embryo will make a bit of heat 

incubating adult has less time to feed

• both parents may share incubation (other brings food)
• one parent may do all the incubating (rely on fat stores)

Question 17

Emperor Penguins

Answer 17

female lays egg
male takes egg immediately
female journeys to feeding grounds ~4 month round trip
female returns, male goes to replenish lost weight (~50% of BW)

Question 18

Esophageal/crop secretions

Answer 18

fed to hatchlings

• sloughed epithelial cells (rich in fat and protein)
• may be fed as only source of food for first 3-5 days
• gradually mixed with solid food over 3-4 weeks