Vahid Vahedi; Babak Naderi; Ciyamak Ghazaie; Azadeh Boustan
Volume 23, Issue 2 , July 2021, , Pages 303-312
Abstract
The aim of this study was the comparison of two protocols of estrus synchronization in two natural climates and heat stress condition on reproductive performance and concentration of plasma estrogen and progesterone hormones in Holstein dairy cows. One hundred and ten multiparous Holstein dairy cows ...
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The aim of this study was the comparison of two protocols of estrus synchronization in two natural climates and heat stress condition on reproductive performance and concentration of plasma estrogen and progesterone hormones in Holstein dairy cows. One hundred and ten multiparous Holstein dairy cows (28 kg average daily milk yield and parity one to four calved) were randomly assigned to two protocol groups: 1) Double-Ovsynch (DO; n=60), the cows received GnRH-7d-PGF2α-2d-GnRH and Ovsynch (GnRH-7d- PGF2α-56h-GnRH-16h-AI) was initiated 7 d later; 2) Presynch-Ovsynch (PO; n=50), the cows received PGF2α-14d-PGF2α and Ovsynch was initiated 12 d later. The both of the protocols were done in two seasons of summer and winter. The calving rate in cows that were synchronized at winter season was greater than cows synchronized in summer (36.4 vs 18.2%; P= 0.04). Mean of the number of insemination to conception was lower in cows that synchronized in winter compared to cows synchronized in summer (1.46 vs 1.74; P= 0.02). Mean of measured estrogen and progesterone hormones concentrations was higher in cows that synchronized in winter compared to summer (P < 0.05). Overall, mean of reproductive traits and hormones concentration is higher in cows that synchronized in winter than in summer and the protocol of estrus synchronization had no effect on reproductive performance.
Mir Hossein Najafi; saeed zeinoaldini; Abolfazl Zali; mahdi Ganjkhanlou; Hossein Mohammadi
Volume 23, Issue 1 , March 2021, , Pages 73-82
Abstract
This study was conducted to investigate the effect of reducing dietary ratio of omega-6/omega-3 essential fatty acid (EFA) on dry matter intake, yield and milk composition, ovarian performance and blood concentrations of estradiol and progesterone using 24 multiparous Holstein cows. Experimental treatments ...
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This study was conducted to investigate the effect of reducing dietary ratio of omega-6/omega-3 essential fatty acid (EFA) on dry matter intake, yield and milk composition, ovarian performance and blood concentrations of estradiol and progesterone using 24 multiparous Holstein cows. Experimental treatments including different n-6 to n-3 EFA ratio; namely, 2.5, 4.5, or 6.5 parts of n-6 to 1 part of n-3 EFA. Dry matter intake and milk yield of cows were recorded daily. Also, body condition score and milk composition were recorded and ovarian activity was monitored by transrectal ultrasound scanning. Dry matter intake and milk composition were not affected by treatments. Daily milk yield was significantly higher in low and medium n- 6/n-3 FA ratio diets in comparison to high diet (P<0.05). Cows assigned to high n-6/n-3 FA ratio diet had greater plasma Haptoglobin concentrations compared to other diets (P<0.05). Results indicated that number of large follicles was greater in medium diet than high diet (P<0.05). Progestrone concentration was significantly decrease in high diet treatment (P<0.05). Results of this study indicate that modulating dietary n-6/n-3 FA ratio could lead to a higher milk yield and improve ovarian performance in fresh cows.
Alireza Talebian Masoudi; Hamidreza Ansari-Renani; Ramezanali Azizi; Azadeh Mirshamsolahi
Volume 20, Issue 1 , May 2018, , Pages 83-94
Abstract
In order to survey slow release mineral-vitamin boluses effects on reproductive performance, wool and follicle structure characteristics of Farahani sheep, 60 head ewes were divided into two control and treatment groups. Control group didn't receive any mineral - vitamin supplement. The treatment group ...
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In order to survey slow release mineral-vitamin boluses effects on reproductive performance, wool and follicle structure characteristics of Farahani sheep, 60 head ewes were divided into two control and treatment groups. Control group didn't receive any mineral - vitamin supplement. The treatment group received slow release mineral-vitamin boluses 15 days before mating. The reproductive performance includes pregnancy rate, lambing rate, abortion rate, weaned rate and means values of fleece weight, staple length, fiber diameter and tenacity of two groups of ewes and secondary to primary follicle ratio(S/P) in treating ewes and their lambs in relation to the control group were evaluated and statistical differences between them were estimated. The result indicated that the slow release mineral-vitamin boluse hadn't significant effect (p
Hamed Kermani Moakhar; Armin Towhidi; Saeed Zeinoldini; Hamid Kohram
Volume 18, Issue 1 , April 2016, , Pages 191-200
Abstract
The aim of this study was to evaluate the effect of glycogenic diets supplemented with different poly unsaturated fatty acids on reproductive performance of Iran Black ewes in two different managing programs. Ewes were allocated in two different groups; group A (n = 75) and group B (n = 25). Ewes from ...
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The aim of this study was to evaluate the effect of glycogenic diets supplemented with different poly unsaturated fatty acids on reproductive performance of Iran Black ewes in two different managing programs. Ewes were allocated in two different groups; group A (n = 75) and group B (n = 25). Ewes from group A were stopped from suckling followed by introducing to the rams on days 80 and 90, respectively. Melatonin implant was laid under the skins ear of these ewes 40 days before introducing them to the rams. Animals from group A were divided into three groups (25 ewes/sub-group) and were fed by high starch diets supplemented with saturated fatty acids (control diet), extruded linseed (omega 3 diet), and full fat soybean (omega 6 diet). Ewes from group B were stopped from suckling on day 120, introduced to the rams on day 180 after parturition and fed as described for the control diet. Data for the rates of Estrus cycle, ovulation, lambing and twining were recorded for each group. The weight of lambs was measured at the birth time of birth, and also at 3 and 4 months of age. The lambing and twining rates were higher in omega 3 and omega 6 diets as compared with the control diet and group B. Animals in group B indicated a higher lamb weight at 3 and 4 months of age compared to all treatments in group A. In conclusion, data from current study suggested that using management program of group A along with feeding omega 3 and 6 could improve the reproductive performance of Iran Black ewes.