The delivery method of [continuous (CONT) vs. every other day or intermittent (INT)] a glucogenic precursor (GP) which was contained glycerin (500 g/kg), mono-propylene glycol (250 g/kg), calcium propionate (150 g/kg), niacin (1 g/kg) and sulfate-Co (350 mg/kg) on performance, selected blood metabolites and liver enzymes were evaluated. Twenty-four multiparous Holstein fresh cows were allocated in a completely randomized design (8 animals/each treatment) fed individually for a period of 14 days after calving. The experimental groups were: 1) no GP supplementation (CTR), 2) GP offered as an oral drench once a day (GP-CONT) on days 3, 4, 5, 6, and 7 after calving and 3) GP offered as an oral drench once a day intermittently (GP-INT) on days 3, 5, 7, 9, and 11 after calving. The amount of oral drenched GP was 1 kg/d. Blood samples were obtained on 5 and 14 days in milk. Dry matter intake (DMI) was increased (P=0.05) in GP-INT cows compared to GP-CONT but not control cows. The yield of fat corrected milk was greater in CTR cows than in GP supplemented cows (P=0.01). The milk protein and fat content were greater for GP-CONT and CTR groups, respectively. Milk somatic cell count was decreased in GP supplemented cows than in CTR cows (64.5 vs. 365×103/mL; P=0.02).Plasma total protein concentration was greater in GP-CONT group. Insulin concentration was increased for GP-CON animals on day 5 (P<0.05). Non-esterified fatty acids and β-hydroxy butyrate as well as liver enzymes were unaltered by treatments. However insulin sensitivity index was lower in supplemented treatments with GP rather than control group (P<0.05). In conclusion, the intermittent delivery of glucogenic precursor may be recommendable in fresh cows based on DMI criteria, which warrants further studies. تفاصيل المقالة

The aim of this study was to compare energy consumption in dairy farms with different sizes. Sources of energy include non renewable sources such as fossil fuel, and electricity and renewable sources such as forage, concentrate, machinery, labor, and water. The required data were collected from 42 dairy farms in Tehran province, Iran and were analyzed to assess energy consumption based on different herd sizes. In this study, the average consumption of non-renewable energy in small, medium, and large dairy farms per kg fat and protein corrected milk were respectively 5.95 MJ kg-1, 3.39 MJ kg-1 and 1.71 MJ kg-1 (P<0.0002). The largest share of energy consumption in all dairy farms was related to feed; 81.49%, 84.37% and 88.62% for small, medium, and large dairy farms, respectively (P<0.0002). Also, energy ratio for small, medium, and large dairy farms were calculated as 0.11, 0.16 and 0.23, respectively (P<0.0001). Likewise, energy productivity in small, medium, and large dairy farms was 0.033 kg MJ-1, 0.047 kg MJ-1 and 0.068 kg MJ-1, respectively (P<0.0001). The less non-renewable energy use per kg fat and protein corrected milk in large dairy farms would lead to reduce pollution and protect the environment which in turn cause to a sustainable and more efficient production system. تفاصيل المقالة

This experiment was performed to investigate whether feeding xylose-treated soybean meal (XSBM) or corn gluten meal (CGM) is economically better under field conditions. Ninety-four multiparous early lactating Holstein cows (55±5 days in milk and 2.82±0.41 body condition score) were used in a completely randomized design. Cows were randomly assigned to one of two treatments: XSBM or CGM as the main rumen undegradable protein source in the diet. Dry matter intake (DMI), milk yield and fat corrected milk (FCM) were not affected by treatments. A tendency was detected for higher FCM: DMI (1.57 vs. 1.47) and income:cost (1.97 vs. 1.83) in CGM treatment. Milk urea nitrogen was greater (15.89 vs. 15.16 mg/dL) in the XSBM group. Plasma glucose, non-esterified fatty acid, beta-hydroxy butyric acid and albumin were not different between treatments. The results showed that under field conditions and feed ingredients used in this experiment, using CGM was economically beneficial during early lactation, which is in contrast with traditional beliefs. تفاصيل المقالة