Effects of walnut shell and chicken manure biochar on in vitro fermentation and in vivo nutrient digestibility and performance of dairy ewes.

Two experiments were conducted to investigate the effects of addition of walnut shell biochar (WSB) and chicken manure biochar (CMB) to dairy ewes' diet. In in vitro experiment, the effects of different levels of WSB and CMB (0.5, 1, and 1.5% diet dry matter (DM)) on rumen fermentation characteristics were assessed in a completely randomized design with seven treatments and three replicates. Treatments were as follows: basal diet without biochar (control), basal diet with 0.5, 1, and 1.5% WSB, and basal diet with 0.5, 1, and 1.5% CMB. Addition of 1% WSB and 1.5% CMB to the diet linearly decreased methane production and ammonia-N concentrations and increased pH compared to control (P < 0.001). Inclusion of WSB and CMB to the diet did not change volume of gas production and total volatile fatty acids (VFA) and proportion of acetate, propionate, and butyrate. In the second experiment, six milking Kermanian ewes were used in a replicated Latin square design with three treatments and three 21-day periods to evaluate the effects of 1% WSB and 1.5% CMB (based on results obtained from in vitro trial) on intake, digestibility, and milk yield and composition. Dietary inclusion of 1% WSB and 1.5% CMB resulted in more milk yield (P < 0.01), milk protein (P < 0.05), and solids not fat (SNF) (P < 0.001). Blood glucose and total protein increased (P < 0.01) in ewes fed 1% WSB and 1.5% CMB in comparison to ewes fed control diet. Apparent digestibility coefficients of DM (P < 0.01) and OM (P < 0.10) were increased with inclusion of 1% WSB and 1.5% CMB in diet. Neutral detergent fiber (NDF) digestibility was also increased in WSB-fed ewes (P < 0.01). The lack of negative effects of 1% WSB and 1.5% CMB coupled with the observed reduction in methane emission and ammonia concentration and also improvement in milk production suggested that biochars can be beneficially incorporated in dairy ewes' ration as a low-cost feed additive.

Effects of processing of starter diets on performance, nutrient digestibility, rumen biochemical parameters and body measurements of brown swiss dairy calves.

In order to investigate the effect of physical forms of starter diets on performance, weaning age, nutrient digestibility and rumen biochemical factors, 24 female of neonatal Brown Swiss calves (average body weight of 39.5±1.2 kg) were randomly assigned to three treatments. Dietary treatments were mashed (MS), pelleted (PS), and texturized (TS) starter using 8 calves from birth till 90 days of age in each treatment. Diets were formulated to be iso-nitrogenous with 21% crude protein. Based on the experimental results, calves that received PS and TS diets, had significant higher average daily gain (ADG) than those receiving MS (p<0.01). Dry matter intake in calves fed PS and TS was greater than calves fed MS (p<0.05), but there was no significant difference in feed efficiency. Treatments had no effect on initiation of rumination. Weaning age of calves in MS was longer than the other two treatments (p<0.05). Crude protein and organic matter digestibility in MS treated calves were lower than other treatments (p<0.05). No differences were observed in neutral detergent fiber (NDF) and ash digestibility among treatments (p>0.05). Ruminal pH was higher (p<0.01) in MS than the other groups, but ruminal ammonia (g/dl) concentration was not different among the treatments. Body measurements such as body length, pin width, hip width, pin to hip length, size of metacarpus and metatarsus bones, hip height, wither height, stomach size and heart girth were not significantly different among the treatments. Overall, it is concluded that starter diets in the form of pellet and texture can improve performance in neonatal Brown Swiss calves compared to the mashed form.

Effects of propylene glycol powder on productive performance of lactating cows.

An experiment was conducted by eight lactating Holstein cows with an average milk production of 32.75 kg day(-1) and body weight of 643.6 kg to evaluate the effects of propylene glycol (PG) on productive performance, blood metabolites and nutrients digestibilities. In this experiment a balanced change-over design with four treatments and four periods with 21 days were employed. Treatments included: (1) Control (without PG), (2) 250 g PG/cow/day, (3) 500 g PG/cow/day and (4) 750 g PG/cow/day. Daily milk yield recorded and milk samples were taken during seven and two last days of each period. The results show that dry matter intake, milk yield, fat corrected milk yield, milk compositions were not affected (p > 0.05) by different levels of PG. Supplementing diets with 500 and 750 g PG/cow/day, significantly increased plasma glucose (p < 0.05) but other blood metabolites such as blood urea nitrogen, triglyceride and cholesterol were not affected (p > 0.05) by PG. Apparent digestibility of dry matter and organic matte was not affected (p > 0.05) by PG administration. In conclusion, plasma glucose was increased by using 500 and 750 g PG/cow/day (as powder) in the first and mid lactation stage, but the levels of 250 g PG/cow/day did not have any significant effect on dry matter intake, milk yield, milk compositions and other blood metabolites.