This study determined the effectiveness of two Lactobacillus buchneri strains (commercial and indigenous) and sodium benzoate (SB) in improving the aerobic stability of corn silage under laboratory and field conditions. Two experiments were carried out to test the following treatments: untreated forage, commercial L. buchneri (CLB), indigenous L. buchneri (ILB) and SB at a 2 g kg−1 concentration. Both inoculants were applied at a rate of 1 × 106 colony forming units of bacteria per gram of forage. In experiment 1, five replicates of each treatment were ensiled in 15‐L laboratory silos. The nutritional, fermentation and microbiological characteristics and aerobic stability of the silage were determined. In experiment 2, the top of a bunker silo was divided into four parts (blocks) along its length before it was sealed, and the treatments were randomly applied. Three bags were buried in each experimental unit (two at the top and one at the core) to determine the loss of dry matter (DM) and the silage characteristics. In experiment 1, ILB exhibited a lower lactic acid concentration and higher 1,2‐propanediol and acetic acid levels, which provided intermediate aerobic stability (67 h). In both experiments, treatment SB exhibited higher residual water‐soluble carbohydrate levels and longer aerobic stability relative to the other treatments. In experiment 2, there were lower DM losses and higher digestibility coefficients when SB was applied, similar to that found at the core. Overall, SB was the most effective additive for improving fermentation, preserving nutrients and reducing the aerobic deterioration of corn silage at the top of a bunker silo in a hot‐climate environment.

The objective of this study was to evaluate 2 systems for covering corn silage in bunker silos. The first system consisted of a sheet of 45-μm-thick oxygen barrier film (OB, polyethylene + ethylene-vinyl alcohol) placed along the length of the sidewall before filling. After filling, the excess film was pulled over the wall on top of the silage, and a sheet of polyethylene was placed on top. The second system involved using a standard sheet (ST) of 180-μm-thick polyethylene film. Eight commercial bunker silos were divided into 2 parts lengthwise so that one-half of the silo was covered with OB and the other half with a ST system. During the filling, 3 net bags with chopped corn were buried in the central part (halfway between the top and bottom of the silo) of the bunkers (CCOR) in 3 sections 10 m apart. After filling, 18 net bags (9 per covering system) were buried 40 cm below the top surface of the 3 sections. These bags were placed at 3 distances from the bunker walls (0 to 50 cm, 51 to 100 cm, and 101 to 150 cm). During unloading, the bags were removed from the silos to determine the dry matter (DM) losses, fermentation end products, and nutritive value. The Milk2006 spreadsheet was used to estimate milk per tonne of DM. The model included the fixed effect of treatment (7 different locations in the bunker) and the random effect of the silo. Two contrasts were tested to compare silages in the top laterals (shoulders) with that in the CCOR (CCOR vs. OB and CCOR vs. ST). Three contrasts compared the corresponding distances of the silage covered by the 2 systems (OB50 vs. ST50, OB100 vs. ST100 and OB150 vs. ST150). Variables were analyzed with the PROC MIXED procedure of the SAS at the 5% level. The OB method produced well-fermented silages, which were similar to CCOR, whereas the OB system showed less lactic acid and greater pH and mold counts compared with CCOR. The ST method had 116.2 kg of milk/t less than the CCOR, as the OB system and the CCOR were similar (1,258.3 and 1,294.0 kg/t, respectively). Regarding the distances from the walls, the effects were more pronounced from 0 to 101 cm. The OB50 and OB100 silages had better quality and lower mold counts and DM losses than ST50 and ST100. The OB system reduced DM and nutrient losses at the shoulders in farm bunker corn silages compared with no sidewall plastic. The OB film should lap onto the crop for at least 200 cm so that 150 cm are covered outward from the wall.

Cows experience a significant negative protein balance during the first 30 d of lactation. Given the functional effects of AA on health, especially in challenging periods such as calving, higher levels of protein and specific AA in the diet may act to improve health and feed intake. The response of dairy cows to 3 protein supplementation strategies during the transition period and through the first 45 d in milk was evaluated. The final data set had 39 Holstein cows blocked based on parity (primiparous vs. multiparous) and expected calving and randomly assigned within each block to one of 3 dietary treatments: low protein (LP), high protein (HP), or high protein plus rumen-protected methionine (HPM). Treatments were offered from d −18 ± 5 to 45 d relative to parturition. Pre-and postpartum diets were formulated for high metabolizable protein (MP) supply from soybean meal, and HP and HPM provided higher MP balance than LP. Preplanned contrasts were LP versus HP+HPM and HP versus HPM. Significance was declared at P ≤ 0.05 and trends at 0.05 < P ≤ 0.10. Cows fed HP and HPM had greater fry matter intake (DMI) prepartum than LP (+2 kg/d), and there was a trend for greater DMI with HPM than with HP (+1.6 kg/d). Body weight and condition score before and after calving did not differ among treatments. High protein (HP and HPM) tended to increase milk yield during the first 45 d of lactation (+1.75 kg/d), increased milk lactose content and urea-N in milk and plasma, tended to increase blood BHB 14 d postpartum, and tended to reduce milk/DMI compared with LP. Blood concentrations of calcium at calving and of glucose, and nonesterified fatty acids pre-and postpartum did not differ. High protein induced lower concentration of plasma IL-1 at calving and lowered blood lymphocytes 21 d postpartum, suggestive of a reduced inflammatory status compared with LP. The concentrations of IL-10, tumor necrosis factor alpha, and other hemogram variables did not differ among treatments. Addition of rumen-protected methionine to the HP diet did not alter milk yield but increased fat and total solids concentrations. The rumen-protected methionine had no effect on blood metabolites and immunity markers, with the exception of increased pre-partum insulin concentrations. The data indicate that dairy cows around calving respond positively to an increase in the supply of MP and to rumen-protected methionine supplementation of the HP diet by increasing intake and improving immune status.

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6 7 8 a Abstract 9 This study examined the intraflock variability of feed efficiency in dairy ewes, through 1 0 monitoring residual feed intakes (RFI). Primiparous lactating ewes (n=43; 57.7±0.91 kg body 1 1 weight [BW] at lambing), representative of a French Lacaune dairy flock, were allocated in an 1 2 equilibrated 2 × 2 factorial design experiment, lasting for 63 days during mid-lactation and 1 3 combining 2 litter sizes (singletons, SING or twins, TWIN) and 2 daily milking frequencies (once, 1 4 ONE or twice, TWO). Ewes were individually fed a diet based on ryegrass silage, local hay and 1 5 supplements. Individual DMI was recorded daily and further used to evaluate (and compare) 1 6differences in RFI between ewes at 35, 42, 49, 56, 63, 70, 77, 84, 91 and 98 days relative to 1 7 lambing (DIM). Total (BW) and metabolic (BW 0.75 ) body weight, BCS, milk yield and plasma 1 8 NEFA were monitored weekly. Differences in DMI were mainly due to the lactation stage and 1 9