Andrology lecture 9 puberty and sex maturity

PUBERTY AND SEXUAL
MATURITY IN MALE ANIMALS
Prof. Dr. G.N Purohit
MVSC, PhD, MNVAS
Dean Post Graduate Studies and University Head Dept. Veterinary
(Gynecology & Obstetrics)
College of veterinary & Animal Science, RAJUVAS
Bikaner, Raj., India.
Email: gnpobs@gmail.com
GOVINDNARAYANPUROHIT(GNPSir)
Dr. GN Purohit – Educational and Confidential - Content collected from different sources Not Permitted for Replication or Commercial Purposes

About Me : Professor G N Purohit, MVSc,Ph.D, MNVAS
Head, Department of Veterinary
Gynecology and Obstetrics, Veterinary
College, Bikaner, Rajasthan, India

Todays Topic –Puberty and sexual maturity
■ <Topic 1> Puberty its signs
■ <Topic 2>Sexual maturity
■ <Topic 3>Factors affecting Puberty
■ <Topic 4>Age of Puberty in different
animals

Puberty in male animals is
defined as the period when
accessory organs and
secondary sexual characters
develop under the influence of
the testes and the animal first
becomes fertile.

Development of Puberty
Puberty in males is characterized by first appearance
of spermatozoa in an ejaculate.
 Primary spermatocytes appear in the seminiferous tubules by 4 to 6 months and
spermatozoa by 7-9 months of age in bulls.
 Seminal secretion from the accessory glands appears by 5-6 months.
 Separation of the penis from the sheath in bulls proceeds caudally beginning at one
month of age and ending with complete separation by 8 months of age.
 The period from 6 to 10 months of age in bulls is characterized by the accelerated
growth of male genital system, increase in GnRH secretion in the hypothalamus,
increase in concentration of LH in plasma, external manifestations of puberty and the
rapid onset of spermatogenesis.
 Attainment of puberty does not signify the full
reproductive capacity in males.

Mechanisms of Puberty in males
■ The testosterone values of the bulls increased with age
from 5-6 months. Prolactin levels in the bulls increased at
the time of the first testosterone rise. A frequency of
about 1-2 LH and FSH pulses/8 h occurred at 1, 2, 5 and
10 months of age.
■ Increased pulse frequencies of GnRH, LH and FSH
precede puberty.

Mechanism for onset of puberty/sex desire
 Onset of puberty in the male domestic animals occurs at
approximately the same time after birth as puberty in
females of the same species.
 It is brought about by the release of gonadotrophic
hormone from the anterior pituitary resulting in the
secretion of steroid hormones from the gonads that
cause growth of genital organs and secondary sex
characteristics.

Dr. GN Purohit - Confidential - Content & Video Not Permitted for Commercial Purposes

Proopiomelanocortin
(POMC)

Signs of puberty
 Onset of puberty in male is characterized by
 Appearance of secondary sexual characters
 Onset of Sexual desire
 Ability to copulate and presence of viable spermatozoa in
the ejaculate
 First appearance of seminal secretion from accessory
sex glands.

Sexual maturity (Age at which the male obtains full reproductive
capacity)
 A highly significant increase in ejaculate volume, output of motile
spermatozoa and concentration of spermatozoa occurs in bulls 6-9
months after the onset of puberty. Hence, there is gap between the
attainment of puberty and full reproductive capacity.
 Sexual maturity follows puberty.
 Because of the lack of maturity after the onset of puberty immature
males should be sparingly used for breeding purposes for
½ to 1 year or more after reaching the puberty.

FACTORS AFFECTING
PUBERTYAND SEXUAL MATURITY
 Onset of puberty and sexual maturity in the male are the gradual
processes which are influenced by
 Plane of nutrition and management.
 Cross breeding.
 Chronic diseases
 Individual differences
 Other factors.

Nutrition and management
 Poor somatic growth and emaciation which ultimately delays the
onset of puberty due to the deficient feeding of protein, iodine,
phosphorus, copper, iron, cobalt.
 The improved nutrition and good management starting at earlier age
enhances the onset of puberty.
 Lack of TDN in the feed or animal get starvated leads to prevent the
secretion of gonadotropic
hormones by the anterior pituitary-
result in failure of early puberty.

Body size and weight
Body weight plays more important role than the
age for attaining puberty and sexual maturity.
If the individual animal gain less weight
according to age factor, the puberty and
ultimately sexual maturity will be delayed.

Gonadal growth
The scrotal circumference is directly proportional to the
intensity of sex desire and spermatozoa production.
Sex desire: Depending on the available testicular
surface area containing number of Leydig cells - site of
androgen secretion.
Spermatozoal production: Depending on the available
testicular surface area containing number of
seminiferous tubule - site for spermatogenesis.
At the age of puberty the diameter of seminiferous
tubules is less than the diameter of the seminiferous
tubules at the age of sexual maturity.

Genetic factors
 The genetic components of young bulls affect the onset
of puberty and maturity.
 The larger breeds of cattle and horses have a late onset
of puberty than the smaller breeds.
 The buffalo male calves appear to attain sexual maturity
later than the cattle-bull calves even with good nutrition
and management; probably due to genetic difference
(testicular surface area of buffalo is lesser than cattle).
 The cross breeding causes early
puberty and maturity.

Species Age at puberty
Bull 9 to 12 Months
(range 6-18 months)
Buffalo Bull 24–30 months of age
Stallion 18 Months
(range 12 to 24 months)
Boar 5 to 7 Months
Ram and Buck 7 to 8 Months
Dog 7 to 10 months
( range 5 to 12 months)
Cat 8 to 10 months
Male camel 3.0 to 3.5 years

Geographical location and Season
 Geographical location
 The geographical location for rearing of young animals affects the onset of puberty and
maturity.
 If individual animal of one geographical area raised in another geographical area, the
puberty will be affected adversely.
 Animals located in tropical regions are late in attaining puberty and sexual maturity.
 Season
 There is a close relationship among season of birth, body weight and onset of puberty.
 Winter is favorable for sexual maturity in young bulls, used in AI.
 Seasonal influences are there in sheep and buffaloes –

Hormones, Chronic disease and debility
and Sexual stimulation
Hormones, Chronic disease and debility
and Sexual stimulation
 Hormones
 If hormone (FSH and ICSH) release occurs at earlier age, the puberty and sexual maturity comes earlier.
 If delay the release of hormones leads to delay in the puberty and sexual maturity.
 Chronic disease and debility
 Any disease which causes emaciation of individual, delay the onset of puberty and sexual maturity. Eg. FMD,
Johne’s diseases, TB, mange.
 Chronic diseases indirectly due to elevation of body temperature, disturbances of basal metabolism, thermal
stress, anorexia, indigestion, stunted growth, emaciation, debility, weakness and endocrinological dysfunction
affects the onset of puberty.
 Sexual stimulation
 The stimulation of sensory apparatus through CNS by hearing, seeing, smelling of opposite sex, causes early
puberty.
 If there is a lack of these stimulation leads to delay the onset of puberty.
 If the male and female are kept together they mature earlier.

Re-cap – What we learned
■ Puberty in male animals is defined as the period when accessory organs and
secondary sexual characters develop under the influence of the testes and the
animal first becomes fertile.
■ Puberty is brought about by the release of gonadotrophic hormone from the anterior
pituitary resulting in the secretion of steroid hormones from the gonads that cause
growth of genital organs and secondary sex characteristics.
■ Puberty is preceded by increased Proopiomelanocortin (POMC), GnRH and LH pulse
frequency
■ Appearance of secondary sexual characters, onset of sex desire and ability to
copulate and presence of viable spermatozoa in the ejaculate.
■ Sexual maturity is the age at which the male obtains full reproductive capacity
usually some time after puberty.
■ Nutrition, environment, heredity and breed affect puberty.

Contact me
Prof. Dr. G.N Purohit
MVSC, PhD, MNVAS
Head Dept. Veterinary (Gynecology & Obstetrics)
College of veterinary & Animal Science, Bikaner, Raj.India.
Email:gnpobs@gmail.com
Linked in : linkedin.com/in/dr-govind-narayan-purohit-13a04a17
YouTube Channel link : https://www.youtube.com/user
/gnpobs61/videos

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Andrology lecture 9 puberty and sex maturity

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