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.
Navid Golestani; Asghar Mogheiseh; Mojtaba Kafi
Volume 20, Issue 3 , November 2018, , Pages 389-399
Abstract
The aim of this study was to determine the incidence and quantify risk factors associated with repeat breeder (RB) syndrome in Isfahan Holstein dairy cows. Calving and insemination data of parities 1 to 7 on 91727 Holstein dairy cows from 62 herds collected during 1993 to 2013 were used. Cows failed ...
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The aim of this study was to determine the incidence and quantify risk factors associated with repeat breeder (RB) syndrome in Isfahan Holstein dairy cows. Calving and insemination data of parities 1 to 7 on 91727 Holstein dairy cows from 62 herds collected during 1993 to 2013 were used. Cows failed to conceive after three or more regularly spaced services in the absence of detectable abnormalities regarded as RB. A multivariate logistic regression model was used to quantify risk factor associated with repeat breeding. Least squares mean number of services per conception were 2.15 ± 0.15 and 2.54 ± 0.15 for normal and RB cows, and uncorrected values were 2.73 and 3.28 for normal and RB cows, respectively. Herd, milk yield, season of calving and season of first insemination, dystocia, stillbirth, abortion and days from calving to first service were the major factors affecting RB syndrome. Average incidence of repeat breeding was 43.7% (27.8-55.2%). Dystocia and stillbirth increased the odds of being RB by 39% and 11%, respectively (P< 0.01). Risk of being RB in high producing cows increased by 79% compared to cows with low milk yield (P< 0.01). Odds of being RB increased by 28% in cows that was RB in previous parity. Fat yield and length of dry period had no significant effect on being RB. Considering at least 75 days distance between calving and first service, insemination in cool seasons, decreasing dystocia and improving reproduction management of high producing cows, could reduce RB syndrome.
Ali Kahyani; G. R. Ghorbani; M. Alikhani; E. Ghasemi; A. Sadeghi-Sefidmazgi; Sayyed Mahmoud Nasrollahi
Volume 20, Issue 3 , November 2018, , Pages 425-435
Abstract
The study was conducted to evaluate indigestible neutral detergent fiber (iNDF) and other related parameters of fiber digestibility of alfalfa hay, corn silage, wheat straw, beet pulp, and wheat bran of a dairy farm. Using two cannulated non-lactating Holstein cows and in situ method, undigested neutral ...
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The study was conducted to evaluate indigestible neutral detergent fiber (iNDF) and other related parameters of fiber digestibility of alfalfa hay, corn silage, wheat straw, beet pulp, and wheat bran of a dairy farm. Using two cannulated non-lactating Holstein cows and in situ method, undigested neutral detergent fiber (uNDF) after 288 h was measured as indicator of iNDF. Then with evaluating the kinetic of fiber digestibility in several time points, the rate and extent of NDF digestibility (NDFD) were measured according to newly-developed equations. The measured NDFD was used for estimation of total tract NDF digestibility (TTNDFD). Alfalfa hay had a greater amount of lignin as well as greater rate of NDF digestion than corn silage and wheat straw. Alfalfa hay and wheat straw, compared with corn silage, had a greater amount of uNDF and lower NDFD and TTNDFD. In spite of having relatively similar amount of NDF, the beet pulp and wheat bran had lower amounts of lignin and uNDF, while greater rate and extent of NDF digestibility as well as TTNDFD than forages. Overall, the considered fibrous feedstuffs showed a considerable variation in uNDF, NDFD, and TTNDFD that must be considered at the time of use.
masood didarkhah; hadi sarir
Volume 20, Issue 2 , August 2018, , Pages 293-304
Abstract
The purpose of this experiment was to evaluate the effect of probiotic and peribiotic supplements on performance of Holstein dairy cows. For this purpose, 40 Holstein dairy cows with daily milk production of 33 ± 0/8 kg and initial weight 700 ± 40 kg were divided into four groups in a completely ...
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The purpose of this experiment was to evaluate the effect of probiotic and peribiotic supplements on performance of Holstein dairy cows. For this purpose, 40 Holstein dairy cows with daily milk production of 33 ± 0/8 kg and initial weight 700 ± 40 kg were divided into four groups in a completely randomized design. The experimental treatments consisted: 1- control group (basic diet) 2- probiotic group (base diet + 4 gr probiotic per head per day) 3- prebiotic group (base diet + 14 gr perbiotypes per Ross per day) 4- Synbiotic group (base diet + 4 gr probiotic + 14 gr perbiotic per head per day). The results of this experiment showed that there was a significant difference between the average duration of chewing, rumination and eating among different diets (P <0.05). The most duration of chewing, rumination and eating belonged to the group that consumed probiotics and had a significant difference with other groups (P <0.05). Probiotics consumption increased the amount of daily milk production, milk production with 3.5% fat and milk production with 4% fat, and a significant difference (P <0.05) with the control group (basal diet without additive). Feed efficiency increased in supplementary rations and resulted in a better performance of probiotic diets. Health indicators, consistency and fluidity of stool in supplementary diets have also improved.