This study measured the effects of including soyhulls as partial roughage replacement in total mixed rations (TMR) fed to 25 pairs of cows during early lactation, on the dry matter (DM) intake, particle kinetics, rumination, in vivo DM and NDF digestibility, milk and FCM yields, and BW changes. The 2 diets used in this study differed in the content of roughage and roughage NDF [23.5 vs. 35.0%, and 12.8 vs. 18.7% in the experimental (EXP) and control (CON) TMR, respectively]. The EXP TMR contained 20.5% less physically effective NDF than the CON TMR (11.7 vs. 14.1% of DM, respectively). These differences were expressed in a greater intake per meal (by 13.3%), a higher rate of meal intake (by 23.2%), a similar number of meals per day, a shorter daily eating duration (by 13%), and a higher total daily DMI (by 7.2%) in the EXP cows as compared with the CON cows. The in vivo DM and NDF digestibility was higher by 4.9 and 22.7%, respectively, in the EXP cows than in the CON cows. The rumination time for the TMR in the EXP cows was 12.7% (54.3 min/d) shorter than in the CON cows, and this was probably related to the difference of 12.4% in physically effective NDF intake between the 2 groups. Patterns of daily rumination and feed consumption throughout an average day showed a delay of approximately 1 to 2 h between the eating and rumination peaks. Particle flow from the rumen of the EXP cows was characterized by a longer rumen mean retention time (by 17.8%) and longer rumination time per kilogram of roughage ingested (by 23.5%) as compared with the CON cows. Thus, favorable conditions for NDF digestion were created in the rumen of the EXP cows, as reflected in their rumen pH values (6.67). The advantage of the EXP cows in intake and digestibility was reflected in a concomitant increase of 7.4% in milk production and of 9.2% in FCM yield as compared with the CON cows. No difference was found between the 2 groups with respect to efficiency of feed utilization for milk production and BW changes.

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The potential of pellets made of soy hulls (SH) and corn gluten feed (CGF) to replace starchy pelleted supplement in diets of lactating cows was measured in a feeding regime comparable to automatic milking systems. Twenty-four cows were divided into 2 equal groups and fed for 7 wk in individual feeders monitored by computer on one of the 2 experimental diets. Both diets contained 75% basic total mixed ration plus an additional 25% of pelleted supplement (17% CP), being either high starch pellets (HST) in treatment, or pellets made of SH + CGF (2:1) (SHCG) in treatment. In vitro dry matter digestibility was higher in the HST pellets, whereas neutral detergent fiber (NDF) digestibility was higher in the SHCG pellets. The NDF content was higher in the SHCG diet. Individual cow behavior at the feeding lane was analyzed during the experimental period. Average number of meals and daily eating duration of the SHCG cows were significantly greater, as compared with the HST group. However, intake per meal and rate of eating were greater in the HST cows, whereas meal duration was similar in both groups. Feeding behavior resulted in significantly higher daily dry matter and NDF intake by the SHCG cows (27.1 and 11.1 kg, respectively) as compared with the HST group (24.8 and 7.61 kg, respectively). Consequently, significantly higher milk fat content, milk fat yield, and 4% FCM yield were obtained in the SHCG cows. Milk and milk protein yields were similar in both treatments. Data suggest potential advantages of the SHCG pellets for herds using automatic milking systems.

This study characterizes the effects of concentrated pomegranate-peel extract (CPE) addition to the TMR at levels of 1, 2, or 4% on voluntary intake, in vivo digestibility, milk yield and composition, and profile of rumen bacterial and archaeal populations in lactating Holstein cows. Supplementation of CPE significantly affected the abundance of methanogenic archaea and specific ruminal bacterial species related to cellulolytic activities and soluble sugar and lactic acid fermentation, as revealed by real-time PCR quantification. Furthermore, CPE supplementation had a significant dose-dependent effect on the whole ruminal bacterial community, as determined by automated ribosomal intergenic spacer analysis. These changes were accompanied by a significant increase in digestibility of dry matter, crude protein, and neutral detergent fiber, as well as milk and energy-corrected milk yields in cows fed the 4% CPE supplement. These results suggest that CPE supplementation significantly affects the rumen bacterial communities, which in turn may be related to a beneficial effect on dairy cow performance.

The effect of growth stage and re-growth on the nutritional and ensilage characteristics of two new sorghum hybrids, BMR-101 and Silobuster, and one commercial variety, FS-5, was examined in this study. Varieties were sampled during the summer at the early heading (EH) stage and were harvested at the soft dough (SD) stage. Additional irrigation enabled autumn re-growth and a second harvest. Plants of FS-5 and BMR-101 were resistant to lodging at EH. However, BMR-101 and Silobuster suffered from high lodging at the SD stage of the summer harvest. Dry matter (DM) content of FS-5 and BMR-101 at EH was below 250 g kg −1 . DM yields of the varieties were similar at the summer harvest and higher than their respective re-growth cuts. Ensilage DM losses were moderate and similar across varieties. Hemicellulose of SD plants was partly solubilised and most of the water-soluble carbohydrate fermented, yielding lactic acid, ethanol and volatile fatty acids (VFA), and a pH < 4. In vitro DM digestibility of varieties was similar in summer silages, but lower in the respective re-growth silages of FS-5 and BMR-101, reflecting the higher content of neutral detergent fibre and lignin in the re-growth silages. The summer plus re-growth cumulative yields of digestible DM of the respective FS-5, Silobuster and BMR-101 silages were 14.7, 16.6 and 14.5 t ha −1 . The commercial variety, FS-5, may have some advantage over BMR-101 and Silobuster owing to its relative resistance to lodging in addition to its high yield and good ensilage properties.

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