Bovine Estrous Cycle.ppt - basu.ac.ir estrous cycle.pdfregression of theregression of the corpus...
16
12/17/2010 1 Bovine Estrous Cycle 1 • Puberty (sexual) • Maturity (physical) 2 The Onset of Puberty has Many Definitions in Females • Age at first estrus (heat). – The first ovulation generally is not accompanied by behavioral estrus in heifers and ewes. This has been termed "silent ovulation.” Thus, the age at first estrus may not reflect true acquisition of puberty. • Age at first ovulation. – it is difficult to determine: palpation, Ultrasonographic imaging, surgical procedures, laparoscopic observation • Age at which a female can Support pregnancy without deleterious effects. 3 Puberty • The age of puberty in domestic species (female) Cow 7 18 mo Defined as the age at which the generative organs become functional and reproduction may occur. – Cow 7-18 mo – Mare 1-2 yr – Ewe 6-15 mo – Goat 4-8 mo – Bitch 6-24 mo – Queen cat 7-12 mo 4 5 6
Transcript of Bovine Estrous Cycle.ppt - basu.ac.ir estrous cycle.pdfregression of theregression of the corpus...
12/17/2010
1
Bovine Estrous Cycle
1
• Puberty (sexual)• Maturity (physical)
2
The Onset of Puberty has ManyDefinitions in Females
• Age at first estrus (heat).– The first ovulation generally is not accompanied by behavioral estrus in
heifers and ewes. This has been termed "silent ovulation.” Thus, the t fi t t t fl t t i iti f b tage at first estrus may not reflect true acquisition of puberty.
• Age at first ovulation.– it is difficult to determine: palpation, Ultrasonographic imaging, surgical
procedures, laparoscopic observation
• Age at which a female can Support pregnancy without deleterious effects.
3
Puberty
• The age of puberty in domestic species (female)Cow 7 18 mo
Defined as the age at which the generative organs become functional and reproduction may occur.
– Cow 7-18 mo– Mare 1-2 yr– Ewe 6-15 mo– Goat 4-8 mo– Bitch 6-24 mo – Queen cat 7-12 mo
4
56
12/17/2010
2
Hormonal Mechanism Of Puberty• LH is the primarily responsible hormone for the onset of
puberty.Gonadostat theory
7
Factors influencing the onset of puberty
1. Nutrition
2. Season
3. Climate
4. Proximity of the male
5. Disease
6. Genotype
8
Oocyte numbers
• Fetal - 2,700,000• Birth - 70,000• Aged - 24 000Aged 24,000
• Number ovulated?>> human ~500>> cow ~350
• Wastage!!
9
The three types of cyclicity are:
• Polyestrus: cattle, swine and rodents,
• Seasollally polyestrus:– short-day breeders: sheep and goats
l d b d– long-day breeder: mare
• Monoestrus: Dogs, wolves, foxes and bears
10
Types of Estrous Cycles as Reflected by Annual E2 Profiles
11
• estrus and estrous– The word estrus is a noun, while estrous is an adjective.
• Oestrus and oestrous– are the preferred spellings in British and European literature.
• Estrus is the period or sexual receptivity.• An estrous cycle is the period between one estrus and
the next.
12
12/17/2010
3
The oestrous cycle is classically divided into four phases:
1. Oestrus, the period of sexual receptivity (day 0)2. Metoestrus, the postovulatory period (days 1–4)3 Di t (d 5 18) h ti3. Dioestrus (days 5–18) when an active corpus
luteum is present4. Pro-oestrus (days 18–20), the period just prior to
oestrus.
13
Stages of the Estrous Cycle
14
The estrous cycle can be divided into two distinct phases:follicular phase and the luteal phase.
15
Phases of the Estrous Cycle
16
Oestrous CycleLength and Definition of Periods
• The oestrous cycle is classically divided into 4 phases:
– Oestrus, the period of sexual receptivity (day 0)
– Metoestrus, the postovulatory period (days 1–4)
– Dioestrus (days 5–18) when an active corpus luteum is present
– Pro-oestrus (days 18–20), the period just prior to oestrus.
17
Oestrous Cycle
• Depending on the dominant structure present in the ovary, the cycle can be subdivided into:
– Follicular phase (pro-oestrus and oestrus) is the period from the regression of the corpus luteum to ovulation and is dominated byregression of the corpus luteum to ovulation and is dominated by oestradiol.
–– Luteal phase (metoestrus and dioestrus) the main ovarian structure is
the corpus luteum, with progesterone as the primary hormone.
18
12/17/2010
4
Folliculogenesis
• Primordial follicle• Primary follicle • Secondary follicle • Tertiary follicle • Graafian follicle
1920
Primordial Follicleيک اليه سلول هاى اپيتليال ساده •
سلول ها در فاز استراحت •
21
Primary follicleاليه فوليکولى تک اليه •
اووسيت اوليه •
zona pellucidazona pellucidaاليه شکل گيرىشکل گيرى •
22
Secondary follicleاليه گرانولوزاى با چند اليه سلولى •
شکل گيرى اليه تيکا •
اووسيت اوليه •
هضض llال idll id zona pellucidazona pellucidaاليهحضورحضور•
عدم وجود حفره انترومعدم وجود حفره انتروم••
23
Tertiary Follicleاليه گرانولوزاى با تعداد اليه هاى سلولى زياد •
وجود اليه هاى تيکاى داخلى و خارجى •
جود حفره انترومجود حفره انترومو •
اووسيت اوليه •
24
12/17/2010
5
Graafian follicleاست tertiary follicletertiary follicleاخرين مرحله •
جود حفره انتروم بزرگجود حفره انتروم بزرگو •
اووسيت اوليه •
مرحله پيش تخمک گذارى •
25
Graafian follicle
26
Estrous Cycle in cow• Follicles grow and regress in a wave-like
manner during the follicular phase
Recruitment Selection Dominance
Dominant Follicle
Subordinate Follicle
27
Follicular wave
28
Follicle DevelopmentFollicular Wave
Growth
Selection
Dominance Regression
Recruitment
SelectionNext Recruitment
Follicle development occurs as a wave-like pattern consisting of“Recruitment”, “Selection”, “Growth”, “Dominance”, and“Regression” phases
Usually 2 to 4 follicular waves occur during the estrous cycle incattle
29
Schematic of follicle growth and FSH for a cow that has two follicular waves during a 21-d estrous cycle
30
12/17/2010
6
31
•
32
33
Estrous
Estrus
proestrusEstrusMetestrusDiestrus
Heat (sexual desire)
34
3536
12/17/2010
7
Signs of Heat1. Primary sign
– Standing heat is the most accurate sign.
2. Secondary signs1. mounting other cowsg2. mucus discharge3. swelling and reddening of the vulva4. sniffing genitalia5. bellowing, restlessness, and trailing6. rubbed tailhead hair and dirty flanks7. chin resting and back rubbing8. decreased feed intake and milk yield
Metestrous bleeding3738
3940
4142
12/17/2010
8
4344
4546
4748
12/17/2010
9
4950
5152
5354
12/17/2010
10
55
Abnormal Estrus• Non-pubertal estrus
– Estrus no ov. no CL
• Silent heat:
E t i t• Estrus in pregnant cows:
• Estrus in cows with folicullar cyst:
56
Factors Affecting Estrous Behavior
1. Type of housing2. Footing surface3. Feet and leg problemsg p4. Temperature5. Variation during the day6. Herdmate status (stage of estrous cycle)7. Lactation number, days postpartum, and milk
production
5758
5960
12/17/2010
11
61
Estrous Detection
• Standing oestrus normally persists for several hours
• Tendency for a higher proportion of oestrous activity to occur at nightto occur at night
• Main period of oestrous activity precedes ovulation by approximately 12–15 hours.
62
Estrous Detection Methods
1. Observation2. Records3. Tail painting4 Kamar4. Kamar5. Vaginal probe6. Milk p4 analysis7. Electronic equipment8. Teaser9. Temperature milk / body63
Tail painting (Chalk)
64
Heat mount detector Kamar Position of detector or tail paste
This device glows when pressure is applied
6566
12/17/2010
12
Pedometers
67
Electrical resistance
Interesting science but limited applicability
68
Bull wearing a chin ball marker
69
Artificial Control of the Oestrous Cycle
70
There are three main approaches:
1. premature luteolysisusing luteolytic agents such as PGF2a. This will obviously only be effective in cycling cows with an active CL.
2. PG-induced luteolysis + GnRH (manipulate follicular and luteal function) Thi d ld t ti ll b d f th i d tiThis procedure could potentially be used for the induction of ovulation in acyclic as well as cyclic cows.
3. simulation of corpus luteum functionby administration of progesterone for a number of days, followed by abrupt withdrawal. This procedure is also effective for the induction of ovulation in acyclic cows.
71
bovine controlled internal drug releaser (CIDR)
progesterone-releasing intravaginal device (PRID).
72
12/17/2010
13
73
Ovsynch
74
Luteal cells
Granulosa cells large luteal cell (granulosaGranulosa cells large luteal cell (granulosa--lutein c.)lutein c.)
Theca cells small luteal cell (thecaTheca cells small luteal cell (theca--lutein c.)lutein c.)
7576
77
• Luteolysis is the process by which the corpus luteum loses its capacity to synthesize and secrete P4.
(Luteolysis) تحليل جسم زرد
• A luteolytic agent is any factor that can reduce luteal P4 synthesis or secretion and/or prevent the action of a luteotrophic hormone.
78
12/17/2010
14
79
What is the signal that initiates the release of PGF2a?
The source of oxytocin initially was considered to be neurohypophysis
subluteolytic
Physiological Review 79:303
80
PGF pathways to luteolysis1) Local counter-current exchange of
PGF2α uterine vein/ovarian artery• Ruminants
2) Local and systemic2) Local and systemic• Swine
3) Systemic• Equine
8182
Mechanism of Luteolytic Action of PGF2a
BovinePate & Keyes 20018384
12/17/2010
15
85
Cycling cowCycling cow
86
8788
8990
12/17/2010
16
Left and right uterine horns
91
Dorsal and ventral intercornual ligaments
92
Developing follicle
93
CL1 with adjacent follicle
94
Four Corpus Albicans (CA) on ovarian surface
95
