The work reported in the Research Communication investigated in vitro rumen gas kinetics and fermentation profile as well as in vivo performance of lactating ewes fed corn silage (CS), sunflower silage (SFS) and their 50 : 50 mixture (CS-SFS). For the in vivo experiment, nine early-lactation Suffolk × Texel ewes were grouped in a replicated 3 × 3 Latin square design of three 21-d periods. Treatments were based on ad libitum CS, SFS, and CS-SFS supplemented with concentrate at 48 g/kg LW0.75. In vitro results showed that the CS had the highest dry matter degraded substrate and microbial crude protein production followed by CS-SFS. The in vivo data showed that animals fed on CS had higher digestibility of dry matter and organic matter than CS-SFS, while SFS were intermediate. Nitrogen (N) intake, fecal N excretion, and urine N excretion were similar between groups, however, milk N excretion was lower in SFS than CS. Milk yield was higher for CS and CS-SFS than SFS group, however, SFS-fed ewes had higher milk fat content than either CS or CS-SFS (all differences reported here were significant, P < 0.05 or better). Overall, CS-SFS could be used as dietary roughage for dairy ewes without deleterious effects on nutrient intake, N-balance and milk yield whilst potentially offering a more sustainable alternative to CS.

Three male sheep were fed, throughout three experimental periods, with either only forage, only total mixed ration (TMR) or a mixed diet (TMR + forage). The rich-fibre ingredients of each diet were incubated daily in situ for three days and the ruminal pH was measured every 2 h during the last day of each experimental period. Rumen pH decreased at increased proportion of TMR in diet (P < 0.05). The dry matter (DM) degradability of the grass forage was higher (P < 0.05) in animals receiving only forage than in those receiving the mixed diet whereas the DM degradability of the corn silage was higher (P < 0.05) in animals receiving the mixed diet than in those receiving only TMR. The level of microbial adherence in residues of grass forage was higher (P < 0.05) in animals fed with only forage than in those fed with the mixed diet and, the level of microbial adherence in residue of corn silage was higher (P < 0.05) in animals receiving the mixed diet than in those receiving TMR. The carboxymethylcellulase activity in residues of grass forage was higher (P < 0.05) in sheep fed the mixed diet whereas not significant effect of diet type was observed for this variable in residues of corn silage. In conclusion, increased inclusion of TMR in sheep diet showed a negative impact on microbial adherence and forage degradability in situ, an effect mediated by changes in rumen pH which was not compensated by increased fibrolytic activity.

The goal of this study was to evaluate the effects of thinning eucalyptus trees on yield and nutritive value of corn for silage and palisadegrass in a crop–livestock–forest integrated system and to evaluate the total aboveground biomass yield in systems with and without trees. Plant variables, as well as the incidence of photosynthetically active radiation (PAR) and soil moisture, were evaluated between October 2016 and March 2018 in São Carlos, Brazil, in a crop–livestock–forest and a crop–livestock system. In the crop–livestock–forest system, eucalyptus trees (Eucalyptus urograndis clone GG100) were planted in April 2011, in single rows, with 15 × 2 m spacing. In 2016, the trees were thinned, and the spacing was changed to 15 × 4 m. The treatments comprised measurements at 0.00, 3.75, 7.50, and 11.25 m from the trees of the North row in the integrated crop–livestock–forest (iCLF) system and integrated crop–livestock (iCL) system. Palisadegrass (Urochloa brizantha) was sown after harvesting the corn. Corn yields were similar between treatments, with an average of 13.6 Mg ha−1. Corn for silage presented a higher percentage of grain in total biomass in the crop–livestock–forest positions (41.4 and 42.1%) than in the crop–livestock system (35.6%). No differences in forage accumulation were observed. Crude protein content in corn for silage and palisadegrass was higher in the crop–livestock–forest treatments than in the crop–livestock system. Such results indicate that thinning was favorable to production in the crop–livestock–forest system. Total aboveground biomass yield was higher in the iCLF system, indicating better land use for this type of integrated system.

Corn silage (CS) is associated with a reduction in milk fat content. The fact that CS is constituted of a grain and a forage fraction could explain this effect. This experiment evaluated the effect of grain fraction of CS on rumen fermentation, production performance and milk composition. Earless CS (ECS) was harvested after manually removing corn ears from the plant. Whole CS (WCS) was harvested from the same field on the same day. Eight (four ruminally fistulated) multiparous Holstein cows (84 days in milk) were utilized in a double 4 × 4 Latin square with 21-day periods. Treatments were (dry matter (DM) basis) (1) 23.0% WCS; (2) 12.4% ECS plus 10.6% high moisture corn (HMC) to obtain reconstituted CS (RCS); (3) 23.0% ECS; and (4) 23.0% timothy silage (TS). Diets were formulated to be isonitrogenous and were fed as total mixed ration once a day. DM intake (DMI), milk yield, 4.0% fat-corrected milk (FCM), as well as protein concentration and yield were higher for WCS than ECS. Compared with WCS, cows tended to eat less with RCS, and produced less milk and milk protein. However, yield of FCM was similar between WCS and RCS. Milk fat concentration and yield, as well as the specific ratio of t11 18:1 to t10 18:1 in milk fat did not differ among diets. Milk urea-N tended to be higher for ECS than WCS and TS, whereas ruminal NH3-N was higher with ECS than TS. Rumen pH decreased linearly with time after feeding but was not different between treatments. Higher acetate and lower propionate concentration resulted in greater acetate to propionate ratio with ECS compared with WCS. In conclusion, removing grain fraction from CS decreased milk production and modified rumen fermentation without affecting milk fat concentration and yield. Moreover, despite some differences in DMI and total ruminal volatile fatty acid concentration between WCS and RCS, the restoration of FCM yield, using HMC in RCS diets, to a level of production similar to WCS highlights the importance of energy and nutrients supplied by the grain fraction of CS to support milk yield.