30 Questions
What is a major factor that influences the age at which heifers reach puberty?
Nutritional history and body size
At what age do Holstein Frisian heifers typically reach puberty?
12-13 months
What is the primary reason why it is recommended to wait after puberty before breeding heifers?
To allow their body organs and tissues to mature
Which breed of heifer typically reaches puberty at the oldest age?
Zebu type
What is the relationship between body weight and puberty in cattle?
Heavier heifers tend to reach puberty earlier
What is the term for the age at which an animal can reproduce well without any body or reproductive problems?
Maturity
What is the primary sign of estrus in a cow?
Standing to be mounted
During which phase of the estrus cycle do metestrus and diestrus occur?
Luteal phase
What is the term used to describe dairy cows' reproductive cyclicity?
Polyestrus
What is the average duration of standing heat in a cow?
15 to 18 hours
Why do cows express signs of heat?
Due to elevated levels of estrogen in the blood when progesterone is very low
What is the endocrine basis for puberty in female dairy cattle?
Development of the hypothalamic mechanisms responsible for GnRH release
What is the average age of onset of puberty in heifers?
9 months
What is the follicular phase of the estrus cycle composed of?
Proestrus and estrus
What is the benefit of decreasing the age at puberty in dairy cattle?
It increases the total lifetime production of the animal
Why is it essential to understand the primary and secondary signs of heat?
To achieve accurate and efficient heat detection
What is the term used to describe the phenomenon of prepuberal heifers displaying estrus without ovulation?
Nonpuberal estrus
What is the primary factor that influences the timing of puberty in dairy cattle?
All of the above
What is a key requirement for the effective use of video cameras in estrous detection?
Videotapes should be reviewed daily
What is a potential benefit of using heat detector animals in estrous detection?
Reducing the time to first service
Why are multiple cameras strategically positioned in the housing area?
To monitor a large proportion of the housing area
What is a disadvantage of using videotaping in estrous detection?
Time-consuming to review videotapes
What is the purpose of using a vasectomized or surgically altered bull in estrous detection?
To serve as a heat detector animal
What is the effect of introducing a bull to a beef herd, according to research?
It shortens the interval to first estrus
What is the average time of insemination relative to calving?
75 days
What happens to the uterus of the cows during the first 42 days postpartum?
It undergoes uterine resorption
What is the conception rate if cows are bred at the first heat after 21 days of parturition?
Less than 25%
What is the purpose of the voluntary waiting period (VWP)?
To allow optimum uterine involution and recovery from negative energy balance
How long is the voluntary waiting period (VWP) in most cases?
50 days postpartum
What happens to the conception rate if cows are bred after 65 days postpartum?
It increases to 60-62%
Learn about the factors that influence puberty age in animals, including breed, body size, nutritional history, and climatic factors. Understand how these factors affect the onset of puberty in different breeds.
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