STUDIES ON THE RECRUDESCENCE OF OESTRUS
POSTPARTUM IN NUBIAN GOATS
By
NAWAL NOUR ELDA-IM OMER
B.V.Sc. University of Khartoum 1991
Supervisor: Dr. Adil Salim El Sheikh
Ph.D. Hokkaido, Japan
A thesis submitted in partial fulfillment of the requirement of
University of Khartoum for Master of Science
Department of Reproduction and Obstetrics
Faculty of Veterinary Medicine
University of Khartoum
December 2003
CONTENTS
Page
DEDICATION
ABBREVIATIONS
LIST OF FIGURES
ACKNOWLEDGEMENT
ABSTRACT
ARABIC ABSTRACT
GENERAL INTRODUCTION
CHPATER ONE: LITERATURE REVIEW
1.1 Postpartum period
1.2. Silent heat (suboestrus heat)
1.3. Factors affecting post-partum period
1.3.1. Milking and suckling
1.3. 2. Milk yield
1.3.3. Nutrition and body condition score
1.3. 4. Season
1.3. 5. Age and parity
1.3. 6. Breed
1.3.7. Uterine infection
1.3. 8. Stress
1.3. 9. Management
1.3.10. Male effect
1.3.11. Uterine involution
1.3. 12. Hormonal influence
a. FSH
b. LH (lutienizing hormone)
c. Oestrogen
d. Progesterone
e. Prostaglandin F2α
f. Oxytocin
i
ii
iii
iv
v
viii
1
4
4
4
5
6
6
8
8
8
8
8
9
9
10
10
10
11
11
12
12
13
14
g. Prolaction
h. Insulin
1.4. Hormonal treatment during postpartum period
1.4.1 Prostaglandin F2α treatment during P.P.
1.4.2. GnRH treatment during P.P.
1.4.3. Oestrogen treatment during P.P.
15
15
16
16
16
16
CHAPTER TWO: MATERIALS AND METHODS
2.1 Study area
2.2 Experimental animals
2.3 Husbandry
i- Health
ii- Feeding
2.4 Oestrous detection technique
2.5 Samples collection and processing
2.6 Progesterone radioimmunoassay
i- P4 R.I.A Kit
ii- Progesterone standards in skim milk
iii- Radioimmunoassay procedures
iv- Counting the radio activity
2.7 Experimental design
2.8 Statistical analysis
17
17
17
17
17
18
18
18
19
19
20
20
21
23
24
CHAPTER THREE: RESULTS
3.1 Experiment I
3.2 Experiment II
3.3 Experiment III
25
25
25
26
CHAPTER FOUR: DISCUSSION
Conclusion and Recommendations
33
37
REFERENCES
39
DEDICATION
To my dear father and my dear mother in spirit live
To my husband and dear lovely daughters
To my sister Amani and brothers Ahmed and Hassan
Abbreviations
- GnRH: Gonadotropin – releasing hormone
- FSH: Follicle – stimulating hormone
- LH: Luteinizing hormone
- PGF2α: prostaglandin F2α
- LHRH: Luteinizing hormone releasing hormone
- CL: Corpus luteum
- RIA: Radioimmunoassay
- EQC: External quality control
- IQC: Internal quality control
- TC: Total count
- CPM: Count per minute
- STD: Standard
- QC: Quality control
- IAEA: International Atomic Energy Agency
- FAO: Food agriculture organization
LIST OF FIGURES
Figure
Title
Page
1
The effect of treatment with PGF2α during the first, 27
second or third week postpartum on the length of
postpartum period in Nubian goats. Means±SE
(a, b, c P<0.05).
2
Milk progesterone profile in postpartum Nubian 28
goats treated with PGF2α during the first week
(n=4), second week (n=4), third week (n=4) and
control (n=5).
3
The effect of treatment with GnRH during the first, 29
second, or third week postpartum on the length of
postpartum of Nubian goats. Means±SE (a, b, P<0.05,
b,c
P<0.001).
4
Milk progesterone profile in postpartum Nubian 30
goats treated with GnRH during the first week
(n=5), second week (n=5), third week (n=5) and
control (n=5).
5
The effect of treatment with GnRH + oestrogen 31
during the first, or the second to third week on the
length of postpartum period of Nubian goats.
Means±SE (a, b, P<0.05, ac-bcP<0.001).
6
Milk progesterone profile in postpartum Nubian 32
goats treated with GnRH + oestrogen during the
first week (n=5), 14-21 days postpartum (n=6) and
control (n=5).
ACKNOWLEDGEMENTS
I would like to express my thanks to Dr. Adil Salim Elshiekh
Department of Reproduction and Obstetrics, Faculty of Veterinary
Medicine, University of Khartoum for his supervision of this study
patiently and with deep interest, valuable observations, and I also
appreciate his guidance, encouragement, advices and his constructive
criticism.
Thanks are duly
extended to Dr. Sharaf A. Makawi,
Department of Reproduction and Obstetrics, Faculty of Veterinary
Medicine, University of Khartoum for his encouragement and advice.
Every gratefulness duly extended to my colleague Dr. Faisal
Omar Department Reproduction and Obstetrics, Faculty of Veterinary
Medicine, University of Khartoum for helping me in the assay of the
milk samples.
I wish to acknowledge my indebtedness to my colleagues at the
National A.I Center, Kuku for their precious assistance and
cooperation special thanks go to Dr. Mohamed Saad, Dr. Magda
A/Elkarim, Mr. Abdel Gadir.
Sincere thanks are due to the staff of goat improvement project
Khartoum State for providing the animals used in this study.
I acknowledge with gratitude the help of the international atomic
energy agency (IAEA) for providing the progesterone kits used in this
study.
Thanks are also extended to Mr. Elmagam for typing this thesis
with deep patience. Also I express my thanks to Eman Mohammed
Abd-elaziz for her help in preparing the final version of the thesis.
Finally I wish express my thanks to every one who directly or
indirectly help me during this study.
STUDIES
ON
THE
RECRUDESCENCE
OF
OESTRUS
POSTPARTUM IN NUBIAN GOATS
Abstract
This study investigated the effects of PGF2α, GnRH or GnRH
plus oestrogen on occurrence of oestrus postpartum (p.p) and the
length of p.p period in Nubian goats. Furthermore, the progesterone (P
4) profiles of the treated goats were compared with untreated controls.
Experiment I:
In this experiment seventeen p.p Nubian goats were allocated to
4 groups and were intramuscularly (i.m) injected with (125 µg)
PGF2α. Group I (n=4), was injected on day 7 p.p; group II (n=4), was
injected on day 15; group III (n=4), was injected on day 21 p.p and
group IV (n=5) was untreated and taken as control. The result of this
study showed that injection of PGF2α during the first week p.p in
Nubian goats has no effect (P > 0.05) on the length of p.p. However,
injection of PGF2α during the second or third week significantly
reduces the time taken for the first oestrus p.p and the length of p.p as
compared with the control (P< 0.01, P< 0.001 respectively). The mean
length of p.p period of goats treat with PGF2α during the first week,
second week, third week and the control were 51± 0.71, 43 ± 0.98, 30
± 0.65, 61± 4.82 days, respectively. The milk P 4 level during p.p
period remained below 0.04 ng/ml in group I; group II; group III and
the control until day 51, 43, 30, 61 p.p, respectively. Thereafter, it
increased to a level of ≥ 1.0 ng/ml.
Experiment II:
In this experiment twenty p.p Nubian goats were used. The
goats were distributed to 4 groups and were injected i.m with 100
µg GnRH. Group I (n=5), was injected on day 7 p.p; group II
(n=5), on day 15 p.p; group III (n=5), on day 21 p.p and group IV
(n=5) was untreated control. The results of this experiment
showed that injection of GnRH during the first, second and third
week p.p in Nubian goats induces the first p.p oestrus earlier (P<
0.05, P< 0.01, P< 0.001 respectively) as compared with the control.
The mean length of p.p period of goat treat with GnRH during the
first week, second week, third week and the control group were
36±1.05,
28±0.71,
27±0.66,
68.8±4.83
days,
respectively.
Furthermore the milk P 4 level remained below 0.04 ng/ml until
day 36, 28, 27 and 68.8 p.p, in goat treated with GnRH during the
first week, second week, third week and the control, respectively.
Thereafter, the P 4 level increased to ≥ 1.0 ng/ml.
Experiment III:
In this experiment sixteen p.p Nubian goats were grouped
into three groups: group I (n=5) was i.m injected with 100 µg
GnRH and (250 µg) of oestradiol benzoate (GnRH + oestrogen) on
day 7 p.p; group II (n=6) was injected between day 15 and 21 and
group III (n=5) was not injected and taken as control. The results
of this experiment showed that injection of GnRH + oestrogen
between the first and third week p.p in Nubian goats reduces
(p<0.01) the time taken for the first oestrus p.p and the length of
p.p period. The means of lengths of p.p periods, of goat in group
I, group II and that of the control, were 27.6±0.51, 21.83±0.98 and
70±2.92 days, respectively. Furthermore, the milk P 4 level of the
treated goats and the control remained below 0. 04 ng/ml until the
occurrence of the first oestrus p.p. Thereafter, it increased to a
level ≥ 1.0 ng/ml.
It is concluded that treatments with PGF2α, GnRH or GnRH +
oestrogen during early p.p reduces the time taken for occurrence of
oestrus p.p and the length of p.p period in Nubian goats.
‫ﺒﺴﻡ ﺍﷲ ﺍﻟﺭﺤﻤﻥ ﺍﻟﺭﺤﻴﻡ‬
‫ﺩﺭﺍﺴﺎﺕ ﺤﻭل ﻋﻭﺩﺓ ﺍﻟﺸﺒﻕ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ‬
‫ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻨﻭﺒﻲ‬
‫ﺃﻭ )‪(PGF2α‬ﺼﻤﻤﺕ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﻟﻤﻌﺭﻓﺔ ﺘـﺄﺜﻴﺭ ﻫﺭﻤـﻭﻥ ﺍﻟﺒﺭﻭﺴـﺘﺎﻗﻼﻨﺩﻴﻥ‬
‫ﺃﻭﺍﻟﻬﺭﻤﻭﻥ ﺍﻟﻤﺤﺭﺭ ﻟﻤﻨﺸﻁﺎﺕ ﺍﻟﻤﻨﺎﺴـل )‪(GnRH‬ﺍﻟﻬﺭﻤﻭﻥ ﺍﻟﻤﺤﺭﺭ ﻟﻤﻨﺸﻁﺎﺕ ﺍﻟﻤﻨﺎﺴل‬
‫ﻋﻠﻰ ﻅﻬﻭﺭ ﺃﻭل ﺸﺒﻕ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻭ ﻁـﻭل )‪(GnRH + Oetrogen‬ﺯﺍﺌﺩﺍ ﺍﻷﺴﺘﺭﻭﺠﻴﻥ‬
‫‪(P4‬ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻨﻭﺒﻲ‪ .‬ﻜﻤﺎ ﺘﻤﺕ ﻤﻘﺎﺭﻨﺔ ﻤﻘﻁـﻊ ﻫﺭﻤـﻭﻥ ﺍﻟﺒﺭﻭﺠﺴـﺘﺭﻭﻥ‬
‫ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻤﻌﺎﻟﺞ ﺒﻬﺫﻩ ﺍﻟﻬﺭﻤﻭﻨﺎﺕ ﺒﻤﻘﻁﻌﻪ ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﻏﻴﺭ ﺍﻟﻤﻌﺎﻟﺞ )ﻤﺠﻤﻭﻋﺔ )‪profile‬‬
‫ﻓﻲ ﺍﻟﺘﺠﺭﺒﺔ ﺍﻷﻭﻟﻰ‪ :‬ﺃُﺴﺘﹸﺨﺩِﻤﺕ ﺴﺒﻌﺔ ﻋﺸﺭ ﺃﻨﺜﻰ ﻤﺎﻋﺯ ﻨﻭﺒﻴﺔ ﻓﻲ ﻓﺘـﺭﺓ ﺍﻟﻨﻔـﺎﺱ‪.‬‬
‫ﺍﻟﺘﺤﻜﻡ(‪.‬‬
‫ﻤﻥ ‪125µg‬ﻗﺴﻤﺕ ﺍﻟﻤﺎﻋﺯ ﺇﻟﻰ ﺃﺭﺒﻌﺔ ﻤﺠﻤﻭﻋﺎﺕ ﻭﺘﻡ ﺤﻘﻥ ﻜل ﻤﺠﻤﻭﻋﺔ ﻤﻨﻬﺎ ﺒﺎﻟﻌﻀل ﺒـ‬
‫ﺤﻘﻨﺕ ﻓﻲ ﺍﻟﻴﻭﻡ ﺍﻟﺴـﺎﺒﻊ ﺒﻌـﺩ ﺍﻟـﻭﻻﺩﺓ‪ .(4 0‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻷﻭﻟـﻰ )ﻋﺩﺩ ‪PGF2α‬ﺍﻟـ‬
‫( ﺤﻘﻨﺕ ﻓﻲ ﺍﻟﻴﻭﻡ ﺍﻟﺨﺎﻤﺱ ﻋﺸﺭ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ‪ .‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻟﺜﺎﻟﺜﺔ ‪4‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻟﺜﺎﻨﻴﺔ )ﻋﺩﺩ‬
‫( ﻟـﻡ ‪ (5‬ﺤﻘﻨﺕ ﻓﻲ ﺍﻟﻴﻭﻡ ﺍﻟﻭﺍﺤﺩ ﻭﻋﺸﺭﻴﻥ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ‪ .‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻟﺭﺍﺒﻌﺔ )ﻋﺩﺩ ‪)4‬ﻋﺩﺩ‬
‫‪(Control) .‬ﺘﹸﺤﻘﻥ ﻭﺃ ﹸﺘﺨِﺫﺕ ﻜﻤﺠﻤﻭﻋﺔ ﺘﺤﻜﻡ‬
‫ﻓﻰ ﺍﻷﺴﺒﻭﻉ ﺍﻷﻭل ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻟﻴﺱ ‪ PGF2α‬ﺃﺜﺒﺘﺕ ﺍﻟﻨﺘﻴﺠﺔ ﺃﻥ ﺤﻘﻥ ﻫﺭﻤﻭﻥ ﺍﻟـ‬
‫ﻋﻠﻰ ﻅﻬﻭﺭ ﺍﻟﺸﺒﻕ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻭ ﻁﻭل ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ ﺇﺫﺍ ﻤﺎﻗﻭﺭﻥ )‪ (P>0.05‬ﻟﻪ ﺘﺄﺜﻴﺭ ﻤﻌﻨﻭﻱ‬
‫ﺒﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﺤﻜﻡ ﻭﻟﻜﻥ ﺤﻘﻨﻪ ﺒﻌﺩ ﺍﻷﺴﺒﻭﻉ ﺍﻟﺜﺎﻨﻲ ﻭﺍﻟﺜﺎﻟﺙ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻴﻌﺠل ﻤـﻥ ﻅﻬـﻭﺭ‬
‫ﺍﻟﺸﺒﻕ ﻋﻘﺏ ﺍﻟﻭﻻﺩﺓ ﻭ ﻴﻘﺼﺭ ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻨﻭﺒﻲ ﻤﻘﺎﺭﻨـﺔ ﺒﻤﺠﻤﻭﻋـﺔ ﺍﻟـﺘﺤﻜﻡ‬
‫؛ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻰ(‪ٍP<0.001,p<0.01)0‬‬
‫ﺒﻌﺩ ﺃﺴﺒﻭﻉ ‪ PGF2α‬ﻤﺘﻭﺴﻁ ﺃﻁﻭﺍل ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻤﻌﺎﻟﺞ ﺒﻭﺍﺴﻁﺔ ﺍﻟـ‬
‫‪±51 0.71 ،‬ﺃﻭ ﺃﺴﺒﻭﻋﻴﻥ ﺃﻭ ﺜﻼﺜﺔ ﺃﺴﺎﺒﻴﻊ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻭ ﻓﻰ ﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﺤﻜﻡ ﻫﻰ ﻜﺎﻵﺘﻲ‪:‬‬
‫ﻴـﻭﻡ ؛ﻋﻠـﻰ ﺍﻟﺘـﻭﺍﻟﻲ‪ .‬ﻭﺇﻥ ﺘﺭﻜﻴـﺯ ﻫﺭﻤـﻭﻥ ‪61 4.82±‬ﻭ‪43 0.98± ، 0.65± 30‬‬
‫ﻓﻲ ﺍﻟﻤﺠﻤﻭﻋﺔ ‪ 0.04 ng/ml‬ﻓﻲ ﺍﻟﻠﺒﻥ ﺍﺜﻨﺎﺀ ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ ﻅل ﺃﻗل ﻤﻥ )‪(P4‬ﺍﻟﺒﺭﻭﺠﻴﺴﺘﺭﻭﻥ‬
‫؛ ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻲ ‪ 61‬ﻭ‪51 ، 43 ، 30‬ﺍﻷﻭﻟﻰ ﻭﺍﻟﺜﺎﻨﻴﺔ ﻭﺍﻟﺜﺎﻟﺜﺔ ﻭﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﺤﻜﻡ ﺇﻟﻰ ﺍﻟﻴﻭﻡ‬
‫‪1.0 ng/ml0‬ﺜﻡ ﺇﺭﺘﻔﻊ ﺇﻟﻰ ﻤﺴﺘﻭﻯ ﻴﺴﺎﻭﻱ ﺃﻭ ﻴﺯﻴﺩ ﻋﻠﻰ‬
‫ﻓﻰ ﺍﻟﺘﺠﺭﺒﺔ ﺍﻟﺜﺎﻨﻴﺔ‪ -:‬ﺇﺴﺘﺨﺩﻤﺕ ﻋﺸﺭﻴﻥ ﺃﻨﺜﻰ ﻤﺎﻋﺯ ﻨﻭﺒﻲ ﻓـﻲ ﻓﺘـﺭﺓ ﺍﻟﻨﻔـﺎﺱ‬
‫‪ GnRH .‬ﻤـﻥ ﺍﻟــ ‪100 µg‬ﻭﻗﺴﻤﺕ ﺇﻟﻰ ﺃﺭﺒﻌﺔ ﻤﺠﻤﻭﻋﺎﺕ ﺘﻡ ﺤﻘﻨﻬﺎ ﺒﺎﻟﻌﻀـل ﺒــ‬
‫‪ (5‬ﺤﻘﻨﺕ ﺒﻌﺩ ﺴﺒﻌﺔ ﺃﻴﺎﻡ ﻤﻥ ﺍﻟﻭﻻﺩﺓ ‪ ،‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻟﺜﺎﻨﻴﺔ )ﻋﺩﺩ ‪(5‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻷﻭﻟﻰ )ﻋﺩﺩ‬
‫ﺤﻘﻨﺕ ﻓﻲ ﺍﻟﻴﻭﻡ ﺍﻟﺨﺎﻤﺱ ﻋﺸﺭ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ‪ ،‬ﻭﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻟﺜﺎﻟﺜﺔ ﺤﻘﻨﺕ ﻓﻲ ﺍﻟﻴـﻭﻡ ﺍﻟﻭﺍﺤـﺩ‬
‫ﻓﺄﺘﺨﺫﺕ ﻜﻤﺠﻤﻭﻋﺔ ﺘﺤﻜﻡ‪(5.‬ﻭﺍﻟﻌﺸﺭﻴﻥ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ‪ ،‬ﺃﻤﺎ ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻟﺭﺍﺒﻌﺔ )ﻋﺩﺩ‬
‫ﻓﻲ ﺍﻷﺴﺒﻭﻉ ﺍﻷﻭل ﺃﻭ ﺍﻟﺜﺎﻨﻲ ﺃﻭ ‪ GnRH‬ﺃﺜﺒﺘﺕ ﻨﺘﻴﺠﺔ ﻫﺫﻩ ﺍﻟﺘﺠﺭﺒﺔ ﺃﻥ ﺤﻘﻥ ﺍﻟـ‬
‫ﺍﻟﺜﺎﻟﺙ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻨﻭﺒﻲ ﻴﺤﺩﺙ ﺸﺒﻘﹰﺎ ﻤﺒﻜﺭﹰﺍ ﻋﻘﺏ ﺍﻟﻭﻻﺩﺓ ﺇﺫﺍ ﻤﺎﻗﻭﺭﻥ ﺒﻤﺠﻤﻭﻋﺔ‬
‫؛ ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻰ( ﻭﺃﻥ ﻤﺘﻭﺴﻁ ﺃﻁﻭﺍل ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ )‪P<0.001 , P<0.01 , P<0.05‬ﺍﻟﺘﺤﻜﻡ‬
‫‪1.05 ± 36‬ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻤﻌﺎﻟﺞ ﻓﻲ ﺍﻷﺴﺒﻭﻉ ﺍﻷﻭل ﻭﺍﻟﺜﺎﻨﻲ ﻭ ﺍﻟﺜﺎﻟﺙ ﻭﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﺤﻜﻡ ﻫﻲ‬
‫ﻴﻭﻡ ؛ ﻋﻠـﻰ ﺍﻟﺘـﻭﺍﻟﻲ‪ 0‬ﻭﺃﻥ ﺘﺭﻜﻴـﺯ ‪،0.71 ±28 ، 0.66 ± 27 ، 4.83 ± 68.8‬‬
‫‪ 1.05 ± 36 ،‬ﺇﻟـﻰ ﺍﻷﻴـﺎﻡ ‪0.04 ng/ml‬ﻫﺭﻤﻭﻥ ﺍﻟﺒﺭﻭﺠﺴﺘﺭﻭﻥ ﻓﻰ ﺍﻟﻠﺒﻥ ﻅل ﺃﻗل ﻤﻥ‬
‫ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻓﻲ ﺍﻟﻤـﺎﻋﺯ ﺍﻟﻤﻌـﺎﻟﺞ ﻓـﻲ ‪0.71 ±28 ، 0.66 ± 27 ، 4.83 ± 68.8‬‬
‫ﺍﻷﺴﺒﻭﻉ ﺍﻷﻭل ﺃﻭ ﺍﻟﺜﺎﻨﻲ ﺃﻭ ﺍﻟﺜﺎﻟﺙ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻭﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﺤﻜﻡ ؛ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻲ‪ 0‬ﺜﻡ ﺇﺭﺘﻔـﻊ‬
‫‪1.0 ng/ml.‬ﺇﻟﻰ ﻤﺴﺘﻭﻯ ﻴﺴﺎﻭﻱ ﺃﻭ ﻴﺯﻴﺩ ﻋﻠﻰ‬
‫ﻓﻲ ﺍﻟﺘﺠﺭﺒﺔ ﺍﻟﺜﺎﻟﺜﺔ ﺍﺴﺘﺨﺩﻤﺕ ﺴﺘﺔ ﻋﺸﺭ ﺃﻨﺜﻰ ﻤﺎﻋﺯ ﻨﻭﺒﻴﺔ ﻓﻲ ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ ﻗﺴﻤﺕ‬
‫ﺇﻟﻰ ﺜﻼﺜﺔ ﻤﺠﻤﻭﻋﺎﺕ ﻭﺤُﻘﻨﺕ ﺒـ‪:‬‬
‫‪Oestradiol benzoate) (GnRH +‬‬
‫‪GnRH 100 µg+ 250 µg‬‬
‫ﺤﻘﻨﺕ ﻓﻲ ﺍﻟﻴﻭﻡ ﺍﻟﺴﺎﺒﻊ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ‪ (5 ،‬ﺒﺎﻟﻌﻀل ‪ ،‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻷﻭﻟﻰ )ﻋﺩﺩ ‪oestrogen‬‬
‫ﻴﻭﻤﹰﺎ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ‪ ،‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻟﺜﺎﻟﺜﺔ ‪ 15 – 21‬ﺤﻘﻨﺕ ﻤﺎ ﺒﻴﻥ ‪(6‬ﺍﻟﻤﺠﻤﻭﻋﺔ ﺍﻟﺜﺎﻨﻴﺔ )ﻋﺩﺩ‬
‫ﻟﻡ ﺘﹸﺤﻘﻥ ﻭﺃﺘﺨﺫﺕ ﻜﻤﺠﻤﻭﻋﺔ ﺘﺤﻜﻡ‪) (5.‬ﻋﺩﺩ‬
‫ﻤﺎﺒﻴﻥ ﺍﻻﺴﺒﻭﻉ ﺍﻷﻭل ‪ GnRH + oestrogen‬ﺃﺜﺒﺘﺕ ﻨﺘﻴﺠﺔ ﻫﺫﻩ ﺍﻟﺘﺠﺭﺒﺔ ﺃﻥ ﺤﻘﻥ‬
‫ﻭﺍﻟﺜﺎﻟﺙ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻴﻌﺠل ﻤﻥ ﻅﻬﻭﺭ ﺍﻟﺸﻴﻕ ﻋﻘﺏ ﺍﻟﻭﻻﺩﺓ ﻭ ﻴﻘﺼﺭ ﻁﻭل ﻓﺘـﺭﺓ ﺍﻟﻨﻔـﺎﺱ‬
‫ﻤﻘﺎﺭﻨﺔ ﺒﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﺤﻜﻡ‪ 0‬ﻭﺃﻥ ﻤﺘﻭﺴﻁ ﺃﻁﻭﺍل ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ ﻟﻠﻤـﺎﻋﺯ ﺍﻟﻤﻌـﺎﻟﺞ )‪(P<0.01‬‬
‫ﺒﻌﺩ ﺍﻷﺴﺒﻭﻉ ﺍﻷﻭل ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻭﻤﺎﺒﻴﻥ ﺍﻷﺴـﺒﻭﻉ ﺍﻟﺜـﺎﻨﻲ ‪GnRH + oestrogen‬ﺒﺎﻟـ‬
‫‪27.6 ± 0.51 ، 21 ± 0.98‬ﻭﺍﻟﺜﺎﻟﺙ ﺒﻌﺩ ﺍﻟﻭﻻﺩﺓ ﻤﻘﺎﺭﻨﺔ ﺒﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﺤﻜﻡ ﻜﺎﻨﺕ ﻜﺎﻵﺘﻰ‬
‫ﻴﻭﻡ ؛ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻲ‪ 0‬ﻭﺃﻥ ﺘﺭﻜﻴﺯ ﻫﺭﻤﻭﻥ ﺍﻟﺒﺭﻭﺠﺴﺘﺭﻭﻥ ﻓﻰ ﺍﻟﻠﺒﻥ ﻅل ﺃﻗل ‪،70 ± 2.92‬‬
‫ﻓﻲ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻤﻌـﺎﻟﺞ ﻓـﻲ ﺍﻷﺴـﺒﻭﻉ ﺍﻷﻭل ‪ 27 ، 21 ، 70‬ﺤﺘﻰ ﻴﻭﻡ ‪0.04 ng//ml‬ﻤﻥ‬
‫ﻭﺍﻟﻤﻌﺎﻟﺞ ﺒﻴﻥ ﺍﻷﺴﺒﻭﻉ ﺍﻟﺜﺎﻨﻲ ﻭﺍﻟﺜﺎﻟﺙ ﻭﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﺤﻜﻡ ﻋﻠﻰ ؛ ﺍﻟﺘﻭﺍﻟﻲ‪ 0‬ﺜـﻡ ﺇﺭﺘﻔـﻊ ﺇﻟـﻰ‬
‫‪ ng/ml 1.0.‬ﻤﺴﺘﻭﻯ ﻴﺴﺎﻭﻱ ﺃﻭ ﻴﺯﻴﺩ ﻋﻠﻰ‬
‫ﺍﻭ ‪GnRH‬ﺃﻭ ‪ PGF2α‬ﺨﻠﺼﺕ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﺇﻟﻰ ﺃﻥ ﺍﻟﻤﻌﺎﻟﺠﺔ ﺒﻭﺍﺴﻁﺔ ﻫﺭﻤﻭﻥ‬
‫ﺨﻼل ﺍﻟﺜﻼﺜﺔ ﺍﺴﺎﺒﻴﻊ ﺍﻷﻭﻟﻰ ﻋﻘﺏ ﺍﻟﻭﻻﺩﺓ ﺘﻌﺠل ﻤﻥ ﻅﻬﻭﺭ ﺍﻟﺸﺒﻕ ‪GnRH + oestrogen‬‬
‫ﻭ ﺘﻘﺼﺭ ﻁﻭل ﻓﺘﺭﺓ ﺍﻟﻨﻔﺎﺱ ﻓﻰ ﺍﻟﻤﺎﻋﺯ ﺍﻟﻨﻭﺒﻰ‪0‬‬
GENERAL INTRODUCTION
The Sudan is endowed with several breeds of endogenous goats
which is the Nubian, Desert, Nilotic, Dwarf and Taggari breed, (FAO,
1991). Nubian goats constitute 2.5 million of the total goat population
in the Sudan (FAO, 1992; AOAD, 1994).
The physical characteristics of Nubian goats were described by
Mason (1988), Devendra and Mcleory (1982), Hassan and Elderani
(1990). Sudanese Nubian goats belong to the general Nubian group
which is characterized by the Roman nose, large drooping ears,
relatively short silky hair of various colours and simple or partially
twisted backwards sweeping horns (Mackenzie, 1967). The colour is
generally black sometimes pure brown, pure white and different
shades between them are found (Mason, 1988; AOAD, 1990). The
distinct advantages of this small ruminant is the small size, low
maintenance cost, rapid growth rate, ability to adapt and convert feed
resources not utilized by other species into animal products. (El-Naim,
1979; Mason, 1988), goats exist because they can survive as meat,
milk and hair producers under conditions which other domestic animal
find difficult to survive on (Williamson and Payne, 1978). In many
countries and also in Sudan goats plays an important role in the
livelihood of many families, beside production of milk they act as a
source of meat, and hair production, food security reserve and recently
goats plays an important role in Sudan economy by their export to
other countries for hard currency.
The most important problems facing the goat dairy farms in the
Sudan are the low milk production, low growth rate and reduced
fertility of local goats breeds. Recently there is a trend to improve the
indigenous goats for milk and meat production by upgrading of
indigenous breeds with exotic pure breed of goats (Saanen, Togenburg
and Anglo-Nubian) introduced to Sudan in 1976, as part of technical
aid of the U.S.A, (Khalaffa and Elshafei, 1990).
Therefore,
considerable crossing was carried between the exotic breeds and
Nubian goats in Khartoum State. Also the Ministry of Agriculture in
Khartoum State imported a herd of Saanen goats from the Netherlands
in (1993) and in 1999 came the technical cooperation project of the
IAEA for goat improvement (Kuku, Khartoum State, Sudan).
Although the goat is economically important for some countries, the
animal is characterized by low reproductive performance in semi-arid
areas as the north-east of Brazil (Fernandez et al., 1987).
One of the
main causes of this low efficiency is the extended interval between
parturition and conception (Oliveria and Lima, 1994). For this reason,
early and accurate pregnancy diagnosis is useful for monitoring the
reproductive performance of herds (Zoli, et al. 1995). Thus, enhancing
the reproductive efficiency of the herds.
Despite these advantages Nubian goats are known to have long
postpartum (p.p) period between 60 – 120 days (Ibrahim, 2000).
Postpartum period which is defined as the interval between parturition
and the first p.p oestrus is an important trait which contributes to the
productive efficiency (Greyling, 2000) the long p.p period will affect
milk and meat production per season. Therefore reduction of the p.p
period can improve the Nubian goats fertility, resulting in production
of at least two kids per year. The p.p ovarian activity in Nubian goats
is not yet fully understood. Therefore, the present study will
investigate the efficiency of different hormones to induce oestrus p.p.
This study was carried out on Nubian goats reared under
improved breeding condition to:determine whether it is possible to reduce the time taken for first
oestrus p.p and the length of p.p period in Nubian goats with
PGF2α.
determine the effect of GnRH on recrudescence of oestrus p.p
in Nubian goats.
c-
determine the time at which Nubian goats return it’s
responsiveness to GnRH p.p.
d-
determine the effect of GnRH plus oestrogen on occurrence of
oestrus p.p and the length of p.p period in Nubian goats.
CHPATER ONE
LITERATURE REVIEW
1.1. Postpartum period (p.p. period)
Postpartum period in dairy goats is the period during which the
uterus and the ovary recuperate their normal non pregnant status, or it
is the period during which recuperation of the uterus occurs after
parturition (Hafez, 1993).
The time from parturition to the first p.p oestrus in cows could
be as short as 15 days or longer than 100 days (Murphy et al., 1990).
Although follicular growth resumes soon after calving failure of
ovulation in dairy cows leads to p.p anoestrus (Savio et al., 1990).
The occurrence of the first postpartum oestrus is an important trait
which contributes to the productive efficiency in goats (Grelying,
2000).
1.2. Silent heat (suboestrous heat)
Silent heat or suboestrous heat denotes the absence of oestrous
behaviour, absence of signs of oestrus or lack of detectable oestrous
behavior (Laing et al., 1988).
Failure to resume signs of oestrus after kidding was found to be
the major problem in dairy cows because silent heats increase the
length of p.p period resulting in a long calving interval (Aboul-Ela and
El-keraby 1986).
The first and second ovulations p.p are not preceded by oestrus
signs and thus are truly silent heats (Morrow et al., 1966; King et al.,
1976).
In dairy herds approximately 90% of silent heats presented for
examination are due to unobserved oestrus while, only 10% are due to
an abnormality that lead to absence of oestrous cycle (Laing et al.,
1988).
1.3. Factors affecting p.p period
1.3.1. Milking and suckling
Milking prolong p.p period in dairy cows whereas weaning
reduces the length of p.p period (Short et al., 1972). Furthermore,
cows nursing a muzzled or nosed plated calves had similar p.p interval
to first-oestrus (Short et al., 1990; Mukasa et al., 1991).
Thus
suckling is one of the major factors that determine the length of p.p
oestrus in dairy animals. Suckling induces suppression of LH resulting
in a low LH concentration in the blood which is associated with a long
p.p anoestrus (Acosta et al., 1983). Also suckling was reported to
extend p.p anoestrus (Peters and Short, 1981; William
et al., 1982;
Wanger and Oxenreider, 1971 and Edward, 1988). Stress of suckling
inhibits adrenal gland resulting in increased blood progesterone and
cortisol, therefore increases the length of p.p period (Mukasa et al.,
1991).
Suckling and/or act of milking apparently inhibits the release of
GnRH necessary for restoration of the pulsatile pattern of LH release,
thus leads to along p.p period (Hafez, 1993). It was proved that the
proportion of does exhibiting oestrus within 60 days p.p was greater
for once daily suckling and early weaning does compared with
continuous suckling does (Lawson et al., 1984). Accordingly it was
interpreted that reducing the suckling stimulus in does during the
breeding season may result in an earlier return to oestrus.
1.3.2. Milk yield
High milk yield is associated with stress which delays the first
p.p oestrus (Gier and Marion, 1968). There is a positive correlation
between high milk yield and increased length of p.p period (Spaddling
et al., 1975). On the contrary, low milk producing cows are known to
have a shorter p.p period (Laing et al., 1988). The same finding was
also reported by William et al. (1982). High milk yield is associated
with high secretion of prolactin and low secretion of prolactin
inhibitory factor secreted by hypothalamus and thus suppressing
gonadotropin releasing hormone leading to low production of
gonadotropin which causes along postpartum period (Hafez, 1993).
Therefore animals that produce milk at a moderate but persistent level
are better than animal that produce high milk yield but have a reduced
persistency (Wood’s, 1976).
1.3.3. Nutrition and body condition score
Inadequate feeding in dairy cows delays p.p period, puberty and
sexual maturity (Williamson and Payne, 1978).
Moreover,
underfeeding is known to cause loss of weight and results in an
oestrus which leads to a long p.p period (Arthur, et al. 1998).
Balanced feeding with enough protein, energy, minerals and vitamins
prevents silent heat and shortens the length of p.p period (Ward et al.,
1971). Feed restriction is known to increase the time taken for the
onset of oestrus (Mani et al., 1992). The body condition score (BCS)
and live weight, which depend mainly on nutrition are intimately
connected to the productivity of domestic ruminants, thus animals
storing surplus of energy in the time of dietary sufficiency have a
short p.p period (Robinson, 1990).
1.3.4. Season
A longer p.p period is reported in Winter and early Spring
(Dekruif, 1978; Montogmery, 1985), also cows calved in Spring have
a longer p.p period than cows calved in Autumn (Peters and Riley,
1982). A significant effect of season on the length of postpartum
period was also reported by Eldon et al. (1990).
Hot seasons are
known to cause heat stress leading to alteration of progesterone level
(Howels, 1981). Furthermore in subtropical climate the expression of
p.p oestrus during Winter is lower than it’s expression in Summer
(Folman, et al., 1984). Postpartum period is influence by season due
to changes in temperature and photoperiod, therefore proper housing
is essential to avoid high temperature in Summer and low temperature
in Winter and control of photoperiod by artificial lighting, induce
early onset of oestrus postpartum (Laing et al., 1988). Occurrence of
first oestrus p.p in Winter is lower than it’s occurrence in Spring
(Llewelyn et al., 1995).
1.3.5. Age and parity
The first oestrus p.p was shorter in middle aged animals and
longer in older one (Gier and Marion, 1968). Younger ewes have
shorter p.p period than older ewes (Blockey and Cumming, 1970).
Primiparous animals have longer p.p period than multiparous ones
(Roberts, 1986). Younger animals giving birth for the first time while
still growing in body size need to grow and produce milk rather than
to reproduce. Animals reaching their seventh lactation period have
poor fertility level (Esslement and Kossaibati, 2000).
1.3.6. Breed
The length of p.p period of different breeds of goats differs
(Riera, 1982; Grelying, 1988). The length of p.p period in Nubian
goats is (50.75±2.62) days (Yagoub, 2003), while Boer goats have a
p.p period of (55.0±24.9) days (Greyling, 2000) and Creole goats have
a p.p period of 21 days (Chemineau, 1983).
Also p.p period is
shorter in West Africa dwarf goats and p.p period is longer in
Egyptian Baladi goats (Akusu et al., 1990; Younis et al., 1989,
respectively).
1.3.7. Uterine infection
Difficulty in parity and uterine infections cause endometritis
which delays p.p period in cows (Arthur et al., 1985). Also retention
of placenta which occurs occasionally in dairy goats leads to a long
postpartum period (Riera, 1982). Moreover, pseudo-pregnancy and
hydrometra in dairy goats delay p.p period (Kornalijnslijper et al.,
1997). Furthermore, any disease that causes abortion and stress
prolongs the p.p period in dairy cows (Hafez, 1993). Ovarian cysts, in
cows with sever endometritis, delayed ovarian rebound and prolonged
p.p period (Mateus et al., 2002).
1.3.8. Stress
Stress such as movement and transport increases ACTH
secretion which in turn stimulates the secretion of corticosteroids
(Arthur et al., 1985). Corticosteroids are known to interfere directly
with ovulation and prolong p.p period (Smith et al., 1973). Most of
diseases in dairy goats that interfere with appetite can prolong p.p
period, especially uterine infections which cause infertility, retained
placenta and meteritis (Hafez, 1993). Stresses caused by weather or
transport are known to cause storm of abortion in (16%) of cows flock
1 to 2 days after stress (Arthur, et al. 1985).
9. Management
Temperature, photoperiod and nutrition are among the factors
that affect the p.p period (Knight et al., 1988). Increment of darkness
to 17 hours/day is known to reduce the time taken for ovarian
rebound, thus leads to a short p.p period (Laing et al., 1988).
Also
housing is a factor that affects the p.p period, proper single grouped
housing pens are better than communal housing (Arthur, et al., 1985).
Improved feeding practices improve ovarian activity and decreases p.p
period, (Prunier et al., 2001).
1.3.10. Male effect
The presence of the male decreases the p.p period by initiation
of ovarian activity because the strong odor of the male plays a role in
induction of oestrus and oestrous behavior (Chemineau, 1987).
The
presence of the male has a possible luteolytic action therefore it
influences ovarian activity immediately after parturition (Chemineau,
1983).
1.3.11. Uterine involution
Uterine involution in goats varies from 28 to 90 days (Side, et
al., 1986). However, it was reported that uterine involution in goats
takes 20-25 days p.p (Laing, 1988).
A period of 28 days p.p for
uterine involution was also reported in Boer goats (Grelying et al.,
1991). Moreover, Rubianes et al. (1990) reported 30 days for uterine
involution in ewes.
1.3.12. Hormonal influence
a. Follicle stimulating hormone (FSH)
FSH is a gonadotrophic hormone secreted by the anterior
pituitary gland in response to the stimulus of gonadotropin releasing
hormone (GnRH), a peptide produced by the hypothalamus (Evans
and Maxwell, 1987). FSH is secreted earlier than the release of LH
postpartum (Hafez, 1998). Plasma FSH increases during the p.p from
low level to higher levels and remains without significant changes
(Peters and Horst, 1984; Schams et al., 1978). Therefore, lower FSH
level p.p extended cyclic ovarian activity (Peter and Riley, 1982).
FSH levels resembling normal oestrus cycles were obtained in p.p
period by GnRH stimulation (Shallenberger
et al., 1978).
Furthermore, FSH response, induced by GnRH injection p.p, was
similar to changes in FSH seen during spontaneous oestrus when a
secondary rise in FSH occurs at the time of preovulatory LH discharge
(L’Hermite et al., 1972).
The basal level of FSH decreases as
oestrogen secretion increases (L’Hermite et al., 1972; Pant et al.,
1977).
The basal out put of FSH from pituitary cells in vivo is
inhibited by suppression of plasma prolactin and oestradiol (Miller
et al., 1977). On the contrary, basal level of plasma FSH is not
affected by reduction of plasma levels of prolactin (Land et al., 1979).
b. Luteinizing hormone (LH)
Leuteinizing hormone (LH) is gonadotrophic hormone secreted
by anterior pituitary under the influence of GnRH (Evans and
Maxwell, 1987).
During 7-10 days p.p L.H is very low and it
increases thereafter to normal level (Kesler et al., 1977; Fernandez et
al., 1987; Schallenberger et al., 1987; Foster and Peters, 1980). The
release of LH p.p affects cyclic ovarian activity (Scham et al., 19780).
Moreover, LH release p.p correlates with time of first ovulation p.p
(Peter and Lamming, 1981). A wide range of variation in LH release
patterns p.p which affects initiation of cyclic ovarian activity is also
known (Llewelyn, et al., 1993).
c. Oestrogen
Oestrogen is a steroid hormone produce by ripe follicular cells
to enhance oestrogen dominated phase (Hafez, 1993). Moreover, the
hormone is produced by placenta during pregnancy. The total
conjugated oestrogens increases progressively from low level in the
first month of pregnancy to moderate level in the mid month of
pregnancy and high level in the late pregnancy (Challis and Linzell,
1971). Before parturition by 26 days the level of oestrogen starts to
increase and after parturition by 2-6 days it decreases (Smith et al.,
1973; Hansel cited by Kinura, et al, 1987). High levels of oestrogen in
blood trigger pituitary gland to release high levels of LH at the onset
of oestrus (Hafez, 1983). This increment in the level of LH is called
preovulatory LH surge. Cyclic ovarian activity is initiated when
higher oestrogen level is obtained (Zaid et al., 1980; Karsch et al.,
1979).
d. Progesterone
Progesterone is a steroid hormone secreted by the adrenal gland,
the corpus luteum in mature animal and by the placenta in late
pregnancy in placental dependant animals. Progesterone produced by
the placenta is five times as much as the progesterone produced by the
ovary (Hafez, 1993). Therefore, progesterone is the main hormone
that regulates oestrus cycle and maintains pregnancy (Hafez, 1993).
Progesterone controls cyclical ovarian activity through a negative feed
back effect on the anterior pituitary gland (Karsch et al., 1983).
Progesterone levels increase from week 3 of pregnancy and remain
high until week 19 of pregnancy and decrease just before parturition
(Sousa et al., 1999). Progesterone concentration from non pregnant
goats at day 20 of the oestrus cycle were lower than 2 ng/ml
(Humblot, 1990; Sousa et al., 1999).). Progesterone concentration
during first week of pregnancy were low in Caninde and Moxoto
goats (0.23, 0.13 ng/ml, respectively) but from week 3 of pregnancy P
4 levels increased (3.35 ng/ml, 4.36 ng/ml, respectively) and remained
high until week 19 of pregnancy (7.96 ng/ml, 5.94 ng/ml),
respectively and decrease just before parturition (3.98 ng/ml, 3.45
ng/ml), respectively. Following parturition progesterone level declines
to
5 ng/ml and remain low until cyclic ovarian activity is
initiated, (Arthur, et al., 1998).
e. Prostaglandin F2α
PGF2α is a derivative of the unsaturated hydroxy acids
lineolenic and arachidonic acids and it is synthesized in the
endometrium of a number of species (Hafez, 1993). PGF2α causes
luteolysis of the corpus luteum (Arthur, et al., 1985). The duration of
release of PGF2α is longer in cow, goat and buffalo than horse and pig
(Kindahl et al., 1982). After parturition there is a sustainable release
of PGF2α that leads to myometrial contractions, explosion of lochia,
and reduction of uterine size, thus it promotes uterine involution of the
uterus (Hafez, 1993). The early postpartum uterus produces large
amounts of PGF2α (Guilbault et al., 1991). The duration of PGF2α
release p.p had a positive correlation with the time required for
completion of uterine involution (Benmard et al., 1986). Increment of
PGF2α secretion postpartum reduces the time for uterine involution
and correlates positively with the rate of service per conception p.p
(Lindel et al., 1982; Young et al., 1984).
f. Oxytocin
Oxytocin had two sites of origin, the hypothalamus and the
corpus luteum. Oxytocin is involved in luteal function by acting on the
endometrium to induce the release of PGF2α which has luteolytic
action (Arthur, et al., 1998). Oxytocin aids ovarian activity postpartum
because it induces expulsion of placenta and aids uterine involution
(Hafez, 1993). Oxytocin reduces progesterone secretion through its
indirect action on the corpus luteum, thus remove the negative feed
back of progesterone upon the hypothalamus and the anterior
pituitary. Consequently oxytocin stimulates GnRH secretion and
induces FSH, LH secretion, leading to follicular growth and
maturation (Schallenberger, et al.1984). Oxytocin did not promote CL
regression in hysterectomized animal indicating that the effect of
oxytocin was uterine dependent (Mirando et al., 1995). Oxytocin
stimulates phospholipase C which promotes endometrial PGF2α
release leading to CL regression (Mirando et al., 1995). Oxytocin
stimulates uterine contractions by increasing PGF2α release (Arthur et
al., 1998).
g. Prolactin
Prolactin is secreted from the anterior pituitary and it is
involved in the formation and maintenance of the corpus luteum
(Evans and Maxwell, 1987).
Prolactin secretion is controlled by
suckling stimulus at the end of pregnancy however; prolactin levels
increase 2-4 days before parturition and continued through p.p period.
The prolactin secretion is high in high lactating animals (Lamming et
al., 1982). Prolactin suppresses GnRH leading to an increased
incidence of silent heat (Hafez, 1993). Prolactin release is dependent
on variation of progesterone levels (Soaje et al., 2002).
High
prolactin levels coincide with anoestrus season and the low prolactin
levels with the breeding season (Prandi, et al. 1988). High level of
prolactin associated with anoestrus is not related to the failure of
progesterone secretion from CL which is formed when ovulation
occur (Robyn et al., 1977).
h. Insulin
Insulin is secreted from the pancreatic cells (Evans and
Maxwell, 1987). Serum insulin like growth factor concentration
correlates with body condition score (BCS). Animals had adequate
BCS had greater serum insulin like growth factor concentration p.p
(Spicer et al., 2002).
High insulin and prolactin concentration is
coincident with a higher number of follicles in cows (Skardaj et al.,
1978). Also high insulin inducing diet increased the proportion of
ovulation and reduced the interval from parturition to first service, that
is to say p.p period (Gong et al., 2002).
1.4. Hormonal treatment during postpartum period
1.4.1 PGF2α treatment during p.p period:There was no report for using PGF2α during p.p period in goats.
However, Grelying and Van Niekerk, (1985) used PGF2α for oestrous
synchronization in dairy goats. Also Bretzlfaff et al., (1978) had
reported the effective dose to produce luteolysis in goats.
Furthermore, corpus luteal cells of goat showed higher sensitivity to
PGF2α than that of sheep (Haresign, 1980)
1.4.2. GnRH treatment during p.p period:GnRH was firstly used between day 10 and 15 postpartum in
Nubian goats by Yagoub, (2003). He reported a short p.p period. Also
Elzubeir (2003) used GnRH during first, second, third week p.p in
dairy cows. He reported a reduced p.p period. GnRH was also used to
induce ovulation in seasonally anoestrous goats (Knight et al., 1988).
1.4.3. Oestrogen treatment in postpartum period:The higher oestrogen in blood triggers pituitary gland to release
high levels of LH at the onset of oestrus (Smith et al., 1973). Using
oestradiol benzoate before single injection of LHRH in seasonally
anoestrous ewe increased LH secretion compared to injection of
LHRH alone (Crighton and Haresign, 1971). An increased pituitary
response to LH-RH after oestradiol pretreatment is also reported
(Arimura and Schally, 1971; Reeves, et al. 1971).
CHAPTER TWO
MATERIAL AND METHODS
2.1 Study area
The experiment was conducted at Helat Kuku in Eastern Nile
province at the main Centre for Goat Production Improvement. It lies
within the semi-arid zone at latitude 15:16 and longitude 32:32, 376
meters above sea level. The average rainfall per year is 167mm.
2.2 Experimental animals
Fifty-three Nubian goats that gave birth were selected from the
main centre for goat production improvement thirty-nine of them were
treated with hormones to shorten the length of the p.p period and
fifteen of them (not treated) were employed as a control to determine
the length of p.p period in dairy goats.
2.3 Husbandry
The animals were housed in a open side-shed. The roof was 3.0
meters in height and was constructed with corrugated, galvanized ion
sheets. The floor was 1.0 meter above the ground made of concrete.
The houses were well ventilated.
i- Health
goats were injected against ecto-and endo parasites with one –
ml/50 kg, Ivermectic (Ivomec, merial, France).
ii- Feeding
Animals were fed 250 g of concentrates made at the farm and
composed of 33% groundnut cake, 33% sorghum (Sorghum vulgare,
Vr. Fetarita), 33% wheat bran and 1% sodium chloride and were
offered Alfa alfa and ad libitum and alfalfa once every day, water
troughs were filled with fresh water twice daily in the morning and
afternoon. The animals were allowed to exercise and to graze once a
week in an adjacent field previously cultivated by misquites shrubs.
2.4 Oestrus detetection technique
Oestrous behaviour was observed twice daily 8.00 a.m and 4.00
p.m. Mature active bucks were introduced to the goats after 2 weeks
p.p. The female goat is considered in oestrus when it allows the buck
to mount her. Llewelyn et al., (1995); Mackenizer (1975); Lindsay
and Fletcher (1972) and Laing (1979). Oestrous occurrence
is
confirmed by progesterone radioimmunoassay. When P4 level in the
milk is above 0.3 ng/ml the goat was considered in the luteal phase of
the first p.p oestrus (Marvogenis, 1987).
2.5 Samples collection and processing
Milk samples
Ten ml of whole milk were collected from p.p goat, every 3
days in milk sample vials. Each 10 ml of the whole milk was
preserved by adding one sodium azide tablet (100 mg) or one
dichromate tablet. The preserved milk was centrifuged at 2500 g for
15 min at room temperature. The centrifuged milk was separated into
fat layer and skim milk. The skim milk was drawn off as follow:
The centrifuged milk was placed in refrigerator at 4oC for 15
minutes to harden the fat layer. A glass rod was used to pierce the fat
layer. The entire skim milk sample was transferred to a storage vial by
using pasteur pipette. The skim milk samples were stored at –20oC
and kept frozen until used.
ii- Progesterone radioimmunoassay
The occurrence of 1st oestrus p.p was confirmed by P4 RIA.
(FAO/IAEA, 1996). Ovulation was assumed to has occurred 4 days
before the first time the milk progesterone values were greater 0.3
ng/ml (Marvogenis, 1987).
2.6 Progesterone radioimmunoassay
i- P4 R.I.A Kit
The kits used for the progesterone assay was brought by the
International Atomic Energy Agency (IAEA) under a technical
cooperation programme for improvement of goat production.
The reagent supplied include:i-
Progesterone antibody coated tubes, in zip-lock
back.
ii-
Buffered progesterone “yellow liquid” antigen.
iii- External quality control samples “E.Q.C”.
iv- Progesterone standards in blood in n mol/L.
ii- Progesterone standards in skim milk
The kit contains seven vials of freeze dried progesterone
standards in processed skim milk (Cadbury’s “Marvel”): they contain
sodium azide as an antibacterial agent.
The standards were constituted by adding 1 ml of distilled water
(pH 6.5-7.5) to each vial, allowed to stand for a minimum of one hour
on the bench then mix gently by vortex. The standards was stored in a
refrigerator. At 2.8oC the standards are stable for at least 30 days after
the reconstitution. The standards provided will cover the physiological
progesterone concentration range prevalent in the skim milk of most
domesticated livestock species. To convert n mol/lit into ng/ml, the
concentrations obtained are divided by 3.18.
iii- Radioimmunoassay procedures
The progesterone assay procedure is done according to FAO,
IAEA assay protocol (1986) version 3.1.
1.
Samples and other components were brought at room
temperature before starting the assay.
2.
Labeled antibody coated tubes for samples, stander internal
quality control (IQC) and external quality control (EQC) were
outlined, and normal tube (not antibody coated) were used for
total count (TC) assay.
3.
The samples, standard and quality control (QC tubes) were
mixed with a vortex mixer (not shaken) prior to each assay.
4.
100 µL of the standards, quality control (QC) and samples were
pipetted into the bottom of corresponding tubes using a
microlitre pipette with fixed disposable plastic tips.
5.
1.0 ml of I125 progesterone was pipetted to each tube within 5
minutes of adding the standards, quality control and samples
using multi-dispenser diluter pipette instrument.
6.
The tubes were covered with Para film or a aluminums foil and
incubated over night in refrigerator (4oC). In cases where
information is needed rapidly, the incubation step is shortened
to 4 hours at room temperature.
7.
After incubation all the tubes were vigorously decanted (all
tubes, except T.C which is placed in a separate rack) into
appropriate radioactive waste disposable pool or container. The
racks were hold upside-down wards on absorbent paper. They
were then allowed to drain for 2.5 min and again were stroked
sharply down wards to remove residual droplets.
iv- Counting the radio activity
A single well gamma counter was used to count the radio
activity of all tubes other wise an appropriate computer program was
employed.
A single well gamma counter was employed for measuring the
radio activity for a fixed time “one minute”. The tubes were placed in
the wells and kept constant maximum percentage binding in the assay
was calculated by dividing the average counts per minute (CPM) of
the two zero standard tubes (B0) by the average CPM of the two T.C
tubes and multiply by 100 as in the equation:Bmax = Average CPM of zero standard (B0) x 100
Average CPM of T.C
T.C is a measure of the status of the tracer. Total count values
below 12,000 – 15,000 CPM indicates a need for caution in
interpreting assay results.
Bmax is a measure of how well the assay is functioning i.e
(how well progesterone binds to the antibody coated on the tubes) if
this value falls below 20 – 25% assay performance should be
considered unsatisfactory and the assay is repeated. Calculate the
percent binding values for all standards, samples and Q.C tubes by
dividing each CPM of these tubes with that of zero standard tubes and
multiplying by 100.
B/B0 = Average CPM of standards, samples P.C x 100
Average C.P.M of B0
Percentage
bound
B/Bo
and
progesterone
standard
concentrations were plotted on vertical Y axis and horizontal ‘X’ of
longitudinal log graph paper. The progesterone concentration of the
samples and quality control were measured by reading their percent
bound values and inter polite from the standard curve to the
progesterone on the x-axis. Alternatively, an appropriate computer
programme was used for calculating the results.
2.7 Experimental design
Experiment I:
This experiment was carried out to determine the effects of
PGF2α on the length of p.p period and on the progesterone profile of
dairy Nubian goats.
Seventeen dairy Nubian goats 2 – 3 years old were used. They
were grouped into 4 groups. Group I (n=4), group (n=4) and group III
(n=4) were i.m injected with 125 µg of PGF2α (Estrumate, Coopers,
England ) (Elnaiem, 2003), on day 7, 15 and 21 p.p, respectively.
Group IV (n=5) was untreated control. Milk samples were collected
every 3 days for P 4 assay. Oestrous detection was done as described
in the materials and methods. The goat was considered in in oestrus 3
days before the level of P4 reaches 0.3 ng/ml or more (Mavrogenis,
1987) .
Experiment II:
This experiment was designed to determine the time at which
Nubian dairy goats return it’s responsiveness to GnRH p.p.
Furthermore, the influence of GnRH on p.p P4 profile was studied.
Twenty p.p Nubian dairy goats were employed. The goats were
grouped into 4 groups. Group I (n=5), group II (n=5) and group III
(n=5) were i.m all injected with 100 µg of GnRH (Fertagyel, Intervet
Boxmeer, Holand) on day 7, 15 and 21 postpartum, respectively
(Yagoub and Elsheikh, 2003). Group IV (n=5) was kept untreated
control. The milk samples were collected every 3 days for P4 RIA.
The oestrous detection method was done as described in the materials
and methods. The goat was considered in oestrus 3 days before the
level of P4 reached 0.3 ng/ml or more.
Experiment III:
This experiment was conducted to study the effect of GnRH
plus oestrogen on p.p period and on the progesterone profile during
postpartum period. Sixteen recently kidded Nubian dairy goats were
used. The goats were distributed to 3 groups. Group I (n=5) and
group II (n=6) were i.m injected with 100 µg of GnRH plus 250 µg of
oestradiol benzoate (Intervet, England) on day 7 and between day 15
to 21, respectively. Group III (n=5) were used as control. The milk
samples were collected as mentioned above. The oestrus was detected
as described in the materials and methods. The goat was considered
in in oestrus 3 days before the level of P4 reaches 0.3 ng/ml or more.
2.8 Statistical analysis
Data were analyzed by one way ANOVA followed by Fisher’s
protected least significant difference. Differences at a probability of P
< 0.05 were considered statistically significant.
CHAPTER THREE
RESULTS
3.1 Experiment I
The result of one way ANOVA showed that injection of PGF2α
during the first week postpartum in Nubian goats has no effect
(P > 0.05) on occurrence of first oestrus p.p and the length of p.p.
However, injection of PGF2α during the second or third week
significantly reduced (P < 0.01, P < 0.001, respectively) the time taken
for recrudescence of oestrus p.p compared to the control, thus,
reducing the length of p.p (Fig. 1).
The mean length of p.p period of goats treat with PGF2α during
the first week, second week, third week and the control group were:
51± 0.71, 43 ± 0.98 , 30 ± 0.65, 61± 4.82 days, respectively.
The milk progesterone level during p.p period remained below
0.04 ng/ml in goats treated with PGF2α during the first, second, third
weeks and the control until day 50, 43, 30, 61 days, respectively. Then
it increased to a level of ≥ 1.0 ng/ml (Fig. 2).
3.2 Experiment II
One way ANOVA showed that injection of GnRH during the
first, second and third week p.p in Nubian dairy goats reduced (P <
0.05, P < 0.01, < 0.001, respectively) the time taken for the first
oestrus p.p as compared to the control, thus resulting in a reduced p.p
(Fig.3).
The mean of p.p period of goats treat with GnRH during the
first week, second week, third week and the control group were:
36±1.05, 28±0.71, 27±0.66, 68.8±4.83 days respectively.
Furthermore the progesterone level remained below 0.04 ng/ml
in goat treated with GnRH during the first week, second week, third
week and the control until day 36, 28, 27 and 68.8 p.p respectively.
Then progesterone level increased to levels ≥ 1.0 ng/ml (Fig. 4).
3.3 Experiment III
The results in this experiment showed that injection of GnRH
plus oestrogen (GnRH + oestrogen) during the first and between the
second and third week p.p in Nubian dairy goats reduced (P < 0.05, P
< 0.001, P < 0.001, respectively) the time taken for occurrence of first
oestrus p.p compared to the control, and reduced the length of p.p
period. The mean lengths of p.p period of goats treated with GnRH
plus oestrogen during the first and between second – third week and
that of the control group were: 27.6±0.51, 21.83±0.98, 70±292 days,
respectively (Fig. 5). Furthermore the progesterone level remained
below 0.04 ng/ml in goats treated with GnRH plus oestrogen during
the first and between the second and third week and that of control
group until day 27, 21, 70 respectively. Thereafter, the progesterone
level increased to a level ≥ 1.0 ng/ml (Fig. 6).
c
70
60
a/c
50
a
40
b
30
20
10
0
First week
Second week
Third week
Control
Fig.1. The effect of treatment with PGF2∝ during the first, second or
third week postpartum on the length of postpartum period in
a, b,c
Nubian goats. Means ± SE (
p<0.05).
Postpartum progesterone concentration (ng/ml)
2.7
First week
2.4
Second week
Third week
2.1
Control
1.8
1.5
1.2
0.9
0.6
0.3
0
0
10
20
30
40
50
60
70
80
Days postpartum
Fig. 2. Milk progesterone profile of postpartum Nubian
goats treated with PGF2∝ during the first week (n=4),
second week (n=4), third week (n=4) and control (n=5).
90
80
c
70
60
50
40
a
b
b
First week
Second week
Third week
(n=5)
(n=5)
30
20
10
0
(n-5)
Control
(n=5)
Fig.3.The effect of treatment with GnRH during the first, second, or
third week postpartum on the length of postpartum of Nubian
a,b
b,c
goats. Means ± SE ( p<0.05, p<0.001).
First week
Second week
2.1
Third week
Control
Progesterone concentration (ng/ml)
1.8
1.5
1.2
0.9
0.6
0.3
0
0
10
20
30
40
50
60
70
Days postpartum
Fig. 4. Milk progesterone profile of postpartum Nubian
goats treated with GnRH during the first week (n=5),
second week (n=5), third week (n=5) and control (n=5).
80
90
80
c
70
60
50
40
30
a
b
20
10
0
First week
2nd to 3rd week
Control
Fig.5.The effect of treatment with GnRH + oestrogen during the first,
or the second to third week on the length of postpartum period
ab
bc- ac
of Nubian goats. Means ± SE ( p<0.05,
p<0.001).
First week
14-21 days
2.1
Control
Progesterone concentration (ng/ml)
1.8
1.5
1.2
0.9
0.6
0.3
0
0
10
20
30
40
50
60
Days postpartum
Fig. 6. Milk progesterone profile of postpartum Nubian
70
80
90
goats treated with GnRH + oestrogen during the first week
(n=5), 14-21 days postpartum (n=6) and control (n=5).
CHAPTER FOUR
DISCUSSION
Prostaglandin F2α has a direct ecbolic effect on bovine uterus,
and increases the tone of uterine muscles, thus increases involution
rate (Lindell and Kindhal, 1982). The complete involution of bovine
uterus is a companied by the recrudescence of oestrous and the first
ovulation followed by a normal luteal phase (Michiel et al., 1999;
Young et al., 1984). Postpartum cows treated with PGF2α between 20
and 24 days postpartum showed a reduced interval to first oestrus
(Benmard and Stevenson, 1986). There is no literature on the effect of
PGF2α on the length of the p.p period in goats.
The results of the present study showed that treatment of
Nubian dairy goats with PGF2α during the second and the third week
p.p reduces the time taken to the first oestrous postpartum and the
length of p.p period. This result agrees with the finding of the above
mentioned studies. However, it some reports showed that PGF2α
treatment during p.p has no effect on occurrence of the first oestrous
p.p in cows (Kindhal et al. 1982; Young et al. 1984).
The results of the present study makes a good base for the use
of PGF2α during p.p period in goats. The progesterone profile reported
in the present study is an indicativor to the recrudescence of p.p
ovulation in treated Nubian goats.
In several studies gonadotrophin releasing hormone (GnRH)
treatment during p.p period in dairy cows is reported to induce ovarian
cyclic activity (Benmard and Stevenson, 1986; Britt et al. 1977;
Gaulbault et al. 1983; Nasir 1990; Fernandez et al. 1987).
Furthermore injection of GnRH during second week p.p in dairy cows
induced recrudescence of first oestrous p.p (Lamming et al. 1982;
Thatcher et al. 1993; Risco et al. 1995). GnRH had indirect and/or
direct action on the ovaries (Chenault et al. 1990; Godfien and
Monroe, 1983; Hsuch and Jones, 1981).
In a recent study a single dose of GnRH on days 10 – 15 post
in dairy Nubian goats reduced the length of p.p period (Yagoub,
2003). The results of this study showed that Nubian goats return their
responsiveness to exogenous GnRH as early as the first week p.p.
Nubian goats treated with GnRH during the first week or between the
second and third week expressed a shorter p.p period. Furthermore,
the increment in the progesterone profile indicates early ovarian
activity. This finding agrees with that of Yagoub, (2003). However, in
this study GnRH was used during the first, and between the second
and third week, while Yagoub used GnRH during the second week
only. Contrary, some authors reported that administration of GnRH in
the early postpartum period did not produce a clear improvement in
reproductive efficiency in cows (Thatcher et al., 1993; Foote and
Riek, 1999). This is in disagreement with the results of the present
study. The difference between the two studies is probably due to a
species difference.
Oestrogen plays an important role in improvement of the
p.p reproductive efficiency in addition to it’s antibacterial effect
(Thatcher, et al. 1993). Thus oestrogen reduces the incidences of
delayed ovulation. When higher oestrogen level is obtained p.p cyclic
ovarian activity is initiated (Zaid et al. 1980; Kesler et al. 1980).
Moreover, high levels of oestrogen in blood trigger pituitary gland to
release high levels of LH at the onset of oestrus (Hafez, 1993).
Oestradiol injection in p.p dairy cows is known to enhance LH
response to GnRH injection (Fernandez, 1987). Also in sheep
estradiol-17β had been shown to enhance PGF2α release by increasing
oxytocin receptors in the endometrium (Wathes and Lamming, 1995).
In the present study oestrogen was combined with GnRH and given
during first, and between the second and third week resulting in a
reduced p.p period.
The early occurrence of oestrus in p.p Nubian goats in the
present study is probably due to triggering of pituitary gland to release
high levels of LH by oestrogen injection. This finding agrees with that
of (Fernandez, 1987).
There was no literature on P4 profile in p.p goats; however,
many authors determine P4 profile during oestrus cycle and pregnancy
in goats (Bauernfein and Holtz, 1990; Pathiraja et al. 1991; Akusu et
al. 1989). Progesterone concentration patterns are similar between
breeds (Sousa et al. 1999). There were several reasons for low P4
concentration in ruminant's species, among these factors, individual
variation (Vahdate et al. 1981. In ovarietomized anoestrous or
oestrous goats P4 concentration in the peripheral circulation were basal
not more than 0.2 ng/ml up to the time of ovulation. These basal levels
on day (0) of oestrous cycle in Nubian goats was reported as
0.59±0.31 ng/ml (El-Naiem, 2003). In this study the progesterone
level during p.p period is very low compared to the normal oestrous
profile. The P4 profile in the p.p goats assumes a general and common
trend starting with basal level then gradually increases to reach a level
of ≥ 1.0 ng/ml.
It is concluded that PGF2α, GnRH or GnRH + oestrogen
treatments during early p.p reduces the time taken for occurrence of
first oestrus p.p and the length of postpartum period in Nubian goats.
Moreover, Nubian goats return their responsiveness to exogenous
GnRH as early as the first week postpartum.
CONCLUSION AND RECOMMENDATIONS
The results of this study illustrate the beneficial use of PGF2α,
GnRH or GnRH + oestrogen postpartum in Nubian goats. The
following conclusion and recommendations could be drawn.
-
A single injection of PGF2α during the second or third week
shortens the length of p.p period and accelerates
occurrence of first p.p oestrus.
-
Injection of GnRH after the first week, the second week or the
third week p.p reduce the time taken for recrudescence
of the first oestrus p.p.
-
Nubian goats return it is responsiveness to GnRH injection after
one week p.p.
-
Injection of GnRH + oestrogen between
the first and the third week postpartum reduces the time taken
for recrudescence of the first oestrus postpartum.
-
Injection of PGF2α or GnRH or GnRH + oestrogen is
recommended for p.p management in Nubian goats.
-
The P4 profile of Nubian goat during the p.p period
starts from a basal level of less than 0.04ng/ml and it increases
after the first oestrus p.p until it reaches a level of
≥1.0 ng/ml.
-
The use of the above mentioned hormones during early
postpartum
in goats will enable the goats breeders to produce two crops every
20
months. Thus increases the milk and kid production.
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Brown, H.M.; Schaenemann and Reeves, J.J. (1983).
Nursing enhances the negative effect of oestrogen on FSH
release in the cow, J. Anim. Sci. 57: 1530- 1536.
Akusu, M.O.E.; Nduka, E. and Soyebo, B.A. (1989). Peripheral
plasma levels of progesterone and oestradiol in West
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