Ali Heidari-Majd; Arash Azarfar; Ayoub Azizi; Hossein Omidi-Mirzaei
Abstract
This study was conducted to investigate the effects of supplementing dairy cows diet with various levels of commercial chestnut condensed tannins (CT) supplement (Silvafeed), on in vitro gas production (GP) and fermentation parameters, nutrients digestibility and activity of rumen microbial enzymes in ...
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This study was conducted to investigate the effects of supplementing dairy cows diet with various levels of commercial chestnut condensed tannins (CT) supplement (Silvafeed), on in vitro gas production (GP) and fermentation parameters, nutrients digestibility and activity of rumen microbial enzymes in vitro using rumen liquor of cow. Dietary treatments were control diet (without CT) and supplementing control diet with CT at the levels of 0.45, 0.90 and 1.35 g per kg dietary dry matter (DM). Inclusion levels of dietary tannins were based on recommendation of manufacturer. Results showed that GP at all of incubation times, potential (b) and rate (c) of GP were not affected by experimental treatments (P>0.05). Except for ammonia nitrogen concentration and microbial protein production which were decreased and increased with increasing rate of CT in the diet respectively (P<0.05), while the other fermentation parameters were unchanged by incubation of experimental diets (P>0.05). Activity of fibrolytic enzymes such a carboxymethyl cellulase, microcrystalline cellulase and filter paper-degrading activity were not affected by supplementing diet with CT (P>0.05), while rumen protease activity was decreased linearly with enhancing level of CT in the diet (P<0.05). In conclusion, the results of present study revealed that adding condensed tannins to dairy cows diet up to 1.35 g/kg dietary DM improved nitrogen metabolism in the rumen, and this could reduce the requirements for dietary rumen undegradable protein.
Hadi Dashti; Ahmad Riasi; Mohammad Ali Edris; Golam-Reza Gohrbani; Hossein Omidi-Mirzaei
Abstract
The aim of this study was to consider reproductive performance parameters and blood progesterone concentration changes in high-producing dairy cows (39±2 kg per day) after artificial insemination, in summer and winter. 270 heads of Holstein dairy cattle were choose in three big dairy farms, and ...
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The aim of this study was to consider reproductive performance parameters and blood progesterone concentration changes in high-producing dairy cows (39±2 kg per day) after artificial insemination, in summer and winter. 270 heads of Holstein dairy cattle were choose in three big dairy farms, and blood samples were collected at days seven, ten and fourteen after artificial insemination. Temperature-humidity index was calculated according to one proposed formula (Dikmen and Hansen, 2009). The results showed that the maximum temperature–humidity index(THI) was 77.35 and 57.47 in summer and winter respectively. Pregnancy rates in cows inseminated during the winter months was significantly higher (p<0.01) than cows inseminated during the summer, and the effects of lactation on conception rate was significant in both seasons (p<0.01). Open days (101.18 vs. 165.07) and number of services per conception (2.05 vs. 3/48) in the winter were significantly lower than cows inseminated during the summer (p<0.01). In day 14 after insemination, blood serum progesterone concentration in cows inseminated in the winter was significantly higher (p<0.01) than summer. Results of this study showed that summer heat stress has significantly affects reproductive performance of dairy cows in central of Iran.
