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English :
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Physiological studies on reproduction in dairy cattle.
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Arabic :
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دراسات فسيولوجية على التناسل في ماشية اللبن.
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| Abstract |
The objectives of this study were to:
1 - Study the effect of supplementation of dietary energy and minerals on
postpartum reproductive performance of Friesian cows, their response to superovulation, and recovered embryos.
2-Study the relationship between blood urea concentration and postpartum reproductive performance, response to superovulation and recovered
embryos.
3 - Study the effect of the presence of dominant follicle on the response to superovulation treatment, diagnosed by ultrasonography.
1- Experimental Design and Methodology:
The work included in this thesis was divided into three parts as follows:
Part I: was designed to examine the effects of dietary dicalcium phosphate
supplementation alone or along with yellow maize and soya bean
supplementation on postpartum reproductive performance of
Friesian cows
Twenty seven Friesian cows with average body weight of 522 kg
were assigned randomly immediately after calving to three similar
groups (9 in each) as follow:
Group 1: Cows in this group were fed on a basal ration (R1), which
consisted of 40% concentrate mixture (CM), 35% berseem (B)
and 25% rice straw (RS) which provide calcium (Ca) and
phosphorus (P) contents of 0.90 and 0.4 % on dry mater (DM)
basis, respectively, as a control group.
Group 2: Cows in this group were fed on a basal ration (R1) along with 50
gm di-calcium basic phosphate supplementation to provide 12.5 g
P per cow daily(0.07 of DM) and dietary P contents of 0.43 and
0.51 % on DM basis. The addition of di-calcium basic phosphate
mainly to correct the balance between Ca and P.
Group 3: Cows in this group were fed the same with group 2 along with 3
kg yellow maize as a percent of 16 % on DM basis and 0.500 kg
soya bean as a percent of 3 % on DM basis. The addition of
yellow maize was to add the source of energy to maximize the
usefullness of high level of protein provided from berseem and the
addition of soya bean.
In analyzing the data obtained in this study, the effects of weight at
calving, and 120-d milk yield were included as dependent regression factors were also included on postpartum reproductive performance.
In addition, the relationships between some blood parameters; namely calcium, phosphorus, total protein and urea and postpartum reproductive performance were also studied.
Part II: was considered as extension of part I, where effects of dietary regimen on response to superovulation and embryo recovery. In addition, the relationships between some blood parameters; namely calcium, phosphorus, total protein and urea and response to superovulation and embryo recovery were also studied.
This part was carried out during mild season (from November to April).Twelve Friesian cows with average body weight of 535 kg were assigned randomly immediately after calving to three similar groups (4 in each) as described in part I.
Part III: was mainly devoted to study follicular waves characteristics during oestrous cycle through ultrasonography, and to examine the effect of the presence of dominant follicle, as monitored by ultrasonography, at the time of PMSG injection on the response to superovulation.
The results obtained could be summarized as follows:
Part I: Postpartum reproductive performance 1-The effect of group on each of SP, DO and CI was statistically significant(P< 0.05) and approached significant for NSC (P = 0.076). However, such effect on DFS was statistically insignificant (P > 0.05).
2- Cows in G3 had shortest SP, NSC, DO and CI (7.6, 1.44, 89.3 and 364.2 d) compared with Gl (37.8,2.25,143.3 and 417.6 d) or G2 (31.4,1.88,108.2 and 393), respectively. G2 had shortest DFS (76.8 d) than G 1 (105.5 d) or G3 (81.8 d).
3- Linear regressions of DO and CI on BW were statistically insignificant (P >0.05), but statistically significant (P < 0.01) on DFS, SP and NSC ( P
<0.05).
4- Effects of linear regression of DO and CI on 120-d MY were statistically insignificant (P < 0.05) and was statistically significant (P < 0.01) on SP and NSC and approached significant on DFS (P = 0.0614).
5- The effect of dietary regimen (group) was statistically highly significant on each of TP (P < 0.001) and U (P < 0.001) and significant for Ca (P < 0.05), but insignificant on P (P > 0.05).
6- The prolongation in reproductive traits was associated with higher concentrations in each of U and P than TP or Ca which was higher in G3, and this was related with longer periods in each of DFS, DO and consequently CI, but these periods were lower than that in G 1.
Part II: Response to superovulation and recovered embryo
1- G 1 (control) had higher number of RE than G2 or G3 (8 vs. 7 or 2),
respectively. The differences may be related to the effect of feed on blood U concentrations, where G3 had highest concentrations (3.229 g/dl) compared to G 1 (2.820 g/dl) or G2 (1.962 g/dl).
2- Gland G2 had higher number of excellent embryos than G3 and this also may be related to the higher plasma U concentrations in G3.
3- The Ca : P ratio may affect on the number ofRE. G3 had Ca : P ratio of2.6 :1 compared with Gl (2.9 : 1) or G2 (3.4 : 1), respectively.
4- G2 had higher number of CL than G 1 or G3 (20 vs. 18 and 9), respectively.
5- The same trend of results for number of CL was observed for the number of RE as described previously for the effect on each of U concentrations and Ca: P ratio.
6-The highest concentrations of TP and U at T4 espicially in G3 may at least partly explain the smaller number of RE and CL in this group and this may be related to their effects on early embryo development and oocyte.
Part III: Follicular dynamics:
1- Follicular development during oestrous cycle occurred mainly in a pattern of two (43.8 %) or three (50 %) waves. Only one case had four waves. In all cases, the preovulatory follicle is derived from the last wave.
2- The length of the oestrous cycle ranged from (18-24 days) according to the number of waves' of oestrous cycle, the length of two, three and four waves were 19.3, 21.3 and 24 days, respectively.
3- The diameter of the dominant follicle was higher in cows with two than those with three waves.
4- Emergence of the first follicular wave occurred at 1.3, 1.0 d while the start of the 2 nd wave at 9.3, 8.4 d for animals with two and three waves, respectively. Emergence of third follicular waves started at day 15.3, on average.
5-The first DF in some cases was still growing and continued for long time, and was > 10 mm at day of PMSG injection and had negative effect on the response to SO treatment. Average no. of ovulations in response to SO was lower in cows where DF was presence on the ovary at time of PMSG injection (1.9) than in those which did not have a detectable DF at time of PMSG injection (4.1).
6- It was concluded that the detection of CL may not be enough to start the protocol of SO treatment because the presence of CL may be related with the presence of DF in 2 nd wave or with follicles> 10 mm. Consequently, this cause a reduction in the response to SO treatment.
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| Publication year |
2006
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| Pages |
148p.
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| Availability location |
مكتبة معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
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| Availability number |
964
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| Organization Name |
Animal Production Research Institute (APRI)
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| Country |
Egypt
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| Department |
Biotechnolog Research Department
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| Author(s) from ARC |
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| Agris Categories |
Animal physiology - Reproduction
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AGROVOC
TERMS |
Cows.
Dairy cattle.
Dicalcium phosphate.
Energy sources.
Maize.
Minerals.
Ovarian follicles.
Perinatal period.
Reproduction.
Reproductive performance.
Soybeans.
Superovulation.
Ultrasonics.
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| Publication Type |
PhD Thesis
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