Term
| What has happened to the market weight of steers over the past 50 years? |
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Definition
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Term
| What has happened to feed efficiency over the past 50 years? |
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Definition
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Term
| What has happened to the fat thickness over the past 50 years? |
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Definition
| it has decreased so the meat is leaner |
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Term
| What has happened to the time to market over the past 50 years? |
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Definition
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Term
| What does the typical growth curve look like? |
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Definition
| like a logistical function |
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Term
| What are the two phases shown in the typical growth curve? |
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Definition
| the self-accelerating phase and the self-retarding phase |
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Term
| What does the rate of growth curve look like? |
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Definition
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Term
| What tissues are of the greatest importance in growth and development in meat animals? |
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Definition
| bone, skeletal muscle, and adispose tissue |
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Term
| What is the growth gradient for muscle like? |
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Definition
- start at the extremities (forelimbs and hindlimbs)
- move upward (chuck and round)
- progress forward from the rump and backwards from the withers
- meet at rib-loin junction
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Term
| With regards to postnatal growth of bone, muscle, and fat, list the order of content from lowest to highest just after birth. |
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Definition
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Term
| With regards to the postnatal growth of fat, muscle, and bone, list the order of content from lowest to highest at maturity. |
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Definition
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Term
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Definition
| process by which cells increase in size |
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Term
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Definition
| growth due to increase in the number of cells |
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Term
| What is accretion? Give examples. |
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Definition
| growth due to the addition of material between cells; connective and scar tissue |
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Term
| What hormone is essential for growth? |
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Definition
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Term
| What factors affect growth? |
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Definition
- genetic determination
- an adequate diet
- freedom from chronic disease and stressful environmental conditions
- normal concentrations of growth-influencing hormones
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Term
| What are the three main functions of growth hormone? |
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Definition
- metabolic actions unrelated to growth
- growth promoting actions on soft tissues
- growth promoting actions on bones
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Term
| How does growth hormone affect metabolic functions unrelated to growth? |
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Definition
- increases lipolysis (increased fatty acid in the blood)
- conserve the glucose
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Term
| With regards to growth promoting actions on soft tissues, what does growth hormone do? |
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Definition
| it causes hyperplasia and hypertrophy |
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Term
| With regards to growth promoting factors on bones, what does growth hormone do? |
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Definition
- stimulates proliferation of epiphyseal cartilage
- stimulates osteoblast activity
- at puberty, the epiphyseal plate is ossified (closed) by action of sex hormone
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Term
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Definition
| it grows from the extremities, not from the middle |
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Term
| What is the section of bone called that is on the outside of the epiphyseal plate? |
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Definition
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Term
| What is the section of bone called that is on te inside of the epiphyseal plate? |
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Definition
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Term
| What is on the very end of bones? |
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Definition
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Term
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Definition
| a rounded end of a long bone |
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Term
| What is the epiphysis filled with? |
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Definition
| red bone marrow, which produces erythrocytes |
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Term
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Definition
| the main or mid section (shaft) of a long bone |
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Term
| What is the diaphysis made up of? |
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Definition
| cortical bone and usually contains bone marrow and adispose tissue |
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Term
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Definition
| a type of bone cell that removes bone tissue by removing its mineralized matrix |
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Term
| What is the process that an osteoclast carries out? |
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Definition
| bone resorption: the process of removing bone's mineralized matrix |
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Term
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Definition
| a mononucleate cell that is responsible for bone formation |
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Term
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Definition
| a connective tissue cell that occupies a lacuna withint the cartilage matrix |
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Term
| Explain the steps that occur during bone growth. |
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Definition
- within the epiphyseal plate, chondrocytes undergo cell division near the epiphyseal bone
- older chondrocytes enlarge
- the extracellular matrix calcifies
- dead chondrocytes are cleared away by osteoclasts within the diaphysis
- osteoblasts swarm up from the diaphysis and deposit bone over the persisting remnants of disintigrating cartilage
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Term
| What allows long bones to grow in length? |
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Definition
| increases in catilage cells (chondrocytes) on the outer edge of the epiphyseal plate followed by hypertrophy and calcification |
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Term
| What causes ossification of the epiphyseal plate? |
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Definition
| estrogen and testosterone |
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Term
| What is growth in bone thickness from? |
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Definition
| osteoblasts and calcification of bone on the outside of the bone in conjunction with loss of bone on the inside by osteoclasts leaving mre space for the bone marrow cavity |
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Term
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Definition
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Term
| How does growth hormone exert its growth promoting effects? |
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Definition
| indirectly by stimulating somatomedins (insulin like growth factors) |
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Term
| What are the two main insulin like growth factors? |
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Definition
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Term
| Where is most og IGF-I from? |
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Definition
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Term
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Definition
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Term
| What does IGF-I production depend on? |
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Definition
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Term
| What other factors affect IGF-I production? |
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Definition
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Term
| IGF-II is independent of ________. |
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Definition
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Term
| IGF-II plays an inportant role during ___________. |
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Definition
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Term
| IGF-II is maybe involved in _______. |
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Definition
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Term
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Definition
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Term
| What are the four types of fat? |
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Definition
- visceral fat
- subcutaneous fat
- intermuscular fat
- intramuscular fat
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Term
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Definition
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Term
| What is subcutaneous fat? |
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Definition
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Term
| What is intermuscular fat? |
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Definition
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Term
| What is intramuscular fat? |
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Definition
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Term
| What are the four types of visceral fat? |
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Definition
- mesenteric fat
- caul fat
- perirenal fat
- leaf fat
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Term
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Definition
| fat deposited in a double layer of peritoneum |
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Term
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Definition
| fatty membranes that surround internal organs |
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Term
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Definition
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Term
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Definition
| the fat that lines the abdominal cavity and encloses the kidneys; used for lard production |
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Term
| Do muscle fiber nuclei divide? Explain. |
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Definition
| no, increases in DNA/fiber during muscle growth due to incorporation of satellite cells |
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Term
| What are satellite cells? |
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Definition
| cells between the myofibrils that aren't activated until the muscle is injured |
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Term
| How does muscle fiber number affect efficiency of weight gain? |
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Definition
| the more muscle fibers, the more efficient the animal is at gainging weight |
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Term
| What does selection for growth affect wih regards to muscle? Explain. |
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Definition
| muscle fiber type; more Type II B fibers |
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Term
| Why is more Type IIB fibers desirable? |
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Definition
- larger size
- lower protein turnover
- greater growth efficiency
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Term
| What is the myoglobin content of Type II B fibers like? |
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Definition
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Term
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Definition
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Term
| What is another name for growth hormone? |
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Definition
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Term
| Where is growth hormone produced? |
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Definition
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Term
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Definition
| a hormone produced by the liver (and other tissues) in response to GH that has a direct impact on growth at the cellular level |
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Term
| What is anothe rname for soamtomedin? |
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Definition
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Term
| Where is somatostatin produced? |
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Definition
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Term
| What does somatostatin inhibit? |
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Definition
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Term
| Where else is somatostatin produced and what else does it do? |
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Definition
| it is also produced by pancreatic delta cells and slows digestion |
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