Related Experiment Video
Updated: Aug 8, 2026

06:38
Determination of Reproductive Competence by Confirming Pubertal Onset and Performing a Fertility Assay in Mice and Rats
Published on: October 13, 2018
Induction of puberty and subsequent reproductive performance
1Animal and Range Sciences Department Montana State University Bozeman, Montana 59717 USA.
Theriogenology
|October 1, 1979
Summary
Inducing puberty in young and light heifers using Synchromate B improved estrus rates but decreased pregnancy success. Light weight heifers had shorter postpartum intervals but lower calf survival.
Area of Science:
- Veterinary Science
- Reproductive Biology
- Animal Science
Background:
- Heifer reproductive efficiency is crucial for herd productivity.
- Early puberty induction aims to improve reproductive outcomes.
- Growth rates and body composition influence reproductive success.
Purpose of the Study:
- To evaluate puberty induction in young and light weight heifers using Synchromate B.
- To assess subsequent reproductive performance and calving outcomes.
- To compare growth rates and estrus synchronization efficacy.
Main Methods:
- A 3-year trial involving control, young age, and light weight heifers.
- Synchromate B treatment administered prior to a 45-day breeding season.
- Estrus, pregnancy rates, calving success, postpartum interval, and calf survival were monitored.
Main Results:
- Young age heifers exhibited significantly lower estrus (47%) and pregnancy rates (7%) compared to controls (91% estrus, 67% pregnancy).
- Light weight heifers showed improved estrus (81%) and pregnancy rates (63%) versus young age heifers, but lower than controls.
- Light weight heifers had a shorter postpartum interval but reduced calf survival (79%) compared to controls (95% calving).
Conclusions:
- Synchromate B was less effective in young age heifers, significantly reducing estrus and pregnancy rates.
- While light weight heifers showed some benefits in estrus and postpartum interval, overall reproductive success was compromised.
- Heifer age and weight at treatment initiation critically impact reproductive performance and subsequent calf survival.
Related Concept Videos
Menopause
Menopause, a natural biological process marking the end of a woman's fertility, typically occurs between the fifth and sixth decade of life. This phase is characterized by the exhaustion of the ovarian follicle pool, leading to less responsive ovaries despite the high levels of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). The consequential decrease in estrogen production results in symptoms like hot flashes, heavy sweating, headaches, hair loss, muscle pains, vaginal...
Development of the Sexual Organs in the Embryo and Fetus
Development of the reproductive organs in an embryo starts from a bipotential state. This means the early embryo can develop either male or female reproductive organs. The formation of these organs begins with the growth of gonadal ridges that arise from the intermediate mesoderm during the fifth week of development.
Near the gonadal ridges, two duct systems are present: the mesonephric ducts (Wolffian ducts) and paramesonephric ducts (Müllerian ducts). These ducts form the basis for the male...
Near the gonadal ridges, two duct systems are present: the mesonephric ducts (Wolffian ducts) and paramesonephric ducts (Müllerian ducts). These ducts form the basis for the male...
Oogenesis
In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from the equivalent procedure of spermatogenesis in males. First, meiotic divisions during oogenesis are asymmetric, meaning that a large oocyte (containing most of the cytoplasm) and minor polar body are produced as a result of meiosis I, and again following meiosis II. Since only oocytes will go on to form embryos if fertilized, this unequal...
Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
The Y Chromosome Determines Maleness
The Y chromosome is a sex chromosome found in several vertebrates and mammals, including humans. In addition to 22 pairs of autosomes, the human males have one X chromosome and one Y chromosome. In these organisms, the presence or absence of the Y chromosome determines the development of male traits.
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size. Today,...
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size. Today,...
Spermatogenesis
Spermatogenesis is a complex process that involves the development of sperm cells from undifferentiated stem cells in the seminiferous tubules of the testes. The process is essential for the production of mature and functional sperm cells that are capable of fertilizing an egg.
The process of spermatogenesis can be divided into mitosis, meiosis, and spermiogenesis. During mitosis, the spermatogonia or stem cells divide to produce two identical daughter cells, type A and B spermatogonia. Type-A...
The process of spermatogenesis can be divided into mitosis, meiosis, and spermiogenesis. During mitosis, the spermatogonia or stem cells divide to produce two identical daughter cells, type A and B spermatogonia. Type-A...

