Recent data indicate positive effects of treating grain with citric (CAc) or lactic acid (LAc) on the hydrolysis of phytate phosphorus (P) and fermentation products of the grain. This study used a semicontinuous rumen simulation technique to evaluate the effects of processing of barley with 50.25 g/L (wt/vol) CAc or 76.25 g/L LAc on microbial composition, metabolic fermentation profile, and nutrient degradation at low or high dietary P supply. The low P diet [3.1g of P per kg of dry matter (DM) of dietary P sources only] was not supplemented with inorganic P, whereas the high P diet was supplemented with 0.5 g of inorganic P per kg of DM through mineral premix and 870 mg of inorganic P/d per incubation fermenter via artificial saliva. Target microbes were determined using quantitative PCR. Data showed depression of total bacteria but not of total protozoa or short-chain fatty acid (SCFA) concentration with the low P diet. In addition, the low P diet lowered the relative abundance of Ruminococcus albus and decreased neutral detergent fiber (NDF) degradation and acetate proportion, but increased the abundance of several predominantly noncellulolytic bacterial species and anaerobic fungi. Treatment of grain with LAc increased the abundance of total bacteria in the low P diet only, and this effect was associated with a greater concentration of SCFA in the ruminal fluid. Interestingly, in the low P diet, CAc treatment of barley increased the most prevalent bacterial group, the genus Prevotella, in ruminal fluid and increased NDF degradation to the same extent as did inorganic P supplementation in the high P diet. Treatment with either CAc or LAc lowered the abundance of Megasphaera elsdenii but only in the low P diet. On the other hand, CAc treatment increased the proportion of acetate in the low P diet, whereas LAc treatment decreased this variable at both dietary P levels. The propionate proportion was significantly increased by LAc at both P levels, whereas butyrate increased only with the low P diet. Treatments with CAc or LAc reduced the degradation of CP and ammonia concentration compared with the control diet at both P levels. In conclusion, the beneficial effects of CAc and LAc treatment on specific ruminal microbes, fermentation profile, and fiber degradation in the low P diet suggest the potential for the treatment to compensate for the lack of inorganic P supplementation in vitro. Further research is warranted to determine the extent to which the treatment can alleviate the shortage of inorganic P supplementation under in vivo conditions.

The present study aimed to investigate changes in the reticuloruminal pH and temperature dynamics in periparturient dairy cows. Reticuloruminal pH and temperature measurements were conducted from 7 d before until 8 d after parturition using indwelling sensors. Nine Simmental and 4 Brown Swiss dairy cows were fed a close-up total mixed ration (52.5% neutral detergent fiber, 5.68MJ of net energy for lactation per kg of dry matter) with additional 1kg/cow per d concentrate mixture (29.5% neutral detergent fiber and 6.25MJ of net energy for lactation per kg of dry matter), starting from 2 wk before the estimated calving date. Postpartum, all cows had free access to the same close-up diet and were gradually fed increasing amounts of a concentrate-rich total mixed ration for early-lactation cows (32.7% neutral detergent fiber, 7.22MJ of net energy for lactation per kg of dry matter). Data showed depressed reticuloruminal pH early postpartum, but only in the group of cows defined as subacute ruminal acidosis (SARA) susceptible (n=8), which had a higher duration time of pH <5.8 (753±82min/d) compared with SARA-tolerant cows (n=5; 15±6min/d). Also, compared with SARA-tolerant cows (112±91min/d), the SARA-susceptible group showed longer (1,049±75min/d) duration time of pH <6.0. When compared by breed, mean reticuloruminal pH tended to be lower in Simmental (6.16±0.03) than in Brown Swiss cows (6.25±0.05), but no differences were observed in the duration of pH <5.8 between breeds. Simmental cows produced more milk (30.4±1.2kg/d) compared with Brown Swiss cows (27.9±1.3kg/d). Neither total dry matter intake nor milk yield were different between SARA-susceptible and SARA-tolerant groups. However, SARA-tolerant cows consumed greater amounts of the close-up total mixed ration than their SARA-susceptible counterparts, whereas no difference was observed in the intake of the early-lactating total mixed ration between the groups. Reticuloruminal temperature was not affected by breed or SARA susceptibility. Interestingly, the mean reticuloruminal temperature and the time duration of temperature >39.5°C abruptly dropped from d 2 to 1 before calving by 0.35°C and 430min/d, respectively. In conclusion, the strong inter-animal variation in reticuloruminal pH responses suggests the need for more careful monitoring and differentiated feeding management of cows during the transition period, whereby the SARA-susceptible cows may require particular attention regarding feeding management and diet composition. The abrupt decrease in reticuloruminal temperature the day before parturition may enable this noninvasive method as a management tool for prediction of parturition time.

Recently there has been renewed interest in foliar fertilization of field crops, but little work with foliar application of nutrients on corn (Zea mays L.) during the grain filling period has been reported. This study was conducted to observe the effect of foliar fertilizer on corn grain yield, yield components, and nutrient content in the grain at harvest, while plants were subjected to moisture stress imposed after silking in one, two, or three successive stress periods. Experiments were conducted in the movable rain shelter facility at Ames, Ia., in 1976 and 1977. In this facility corn plants were grown in containers containing 100 liters of a Nicollet loam soil (an Aquic Hapludoll, fine‐loamy mixed mesic). Foliar fertilizer was applied three times in the post‐silking period with a pressurized hand sprayer. In 1976, foliar fertilizer application commenced 4 weeks after silking, and no significant effect of foliar fertilizer on yield, or yield components was measured. In 1977, foliar‐fertilizer application commenced as early as 2 weeks after silking, and a significant, 6.4% yield reduction occurred in foliar‐fertilizer treatments. This decrease occurred in both hybrids used and in all moisture‐stress treatments. There was no evidence for an interaction between post‐silking moisture stress and foliar‐fertilizer application. In 1977, the effect of foliar fertilizer was to reduce mass/kernel in one hybrid, while in the other, neither mean mass/kernal nor kernels/plant were significantly reduced, but total grain yield was reduced. This difference was related to the number of days after silking when foliar fertilizer was first applied. Foliar fertilizer seemingly produced a stress on these plants, and the deleterious effect of this stress was expressed by the yield component being primarily determined at the time the stress occurred. Foliar fertilizer applications resulted in a significant increase in the percent N (10%) and in the percent P (4.7%) in the grain at harvest. There was, also, an increase in N yield (5.1%) in the grain despite a grain yield decrease in one hybrid.

An enrichment of foodstuffs with RS and dietary fiber is meaningful for a healthier diet. Main goal of this research was to evaluate the effects of treating barley with citric acid (CA), lactic acid (LA), separately or together, and with the enzyme pullulanase (PUL) on RS and the contents of main nutrients of four barley genotypes. Treatment with PUL increased the RS content from 0.26 (control) to 1.29%. Enhancement of RS was also observed with 5% LA as well as with 5% CA, but these effects were barley genotype‐dependent. Treatment with CA increased the organic residue, a fraction that includes (1 → 3,1 → 4)‐β‐glucan, from 10.2 to 14.0%. Ash contents decreased from 2.42 to 1.98% by LA treatment and neutral detergent fiber decreased from 14.1 to 8.4% by CA treatment, depending on the used barley genotype. In conclusion, data indicated that treating barley with organic acids or PUL may have the potential to enhance the RS and beneficially modulate nutrient composition of barley. Further research is warranted to understand the mechanisms behind the effects observed herein and their nutritional implications in the diet.

Exposure to mycotoxin-contaminated feeds represents a serious health risk. This has necessitated the need for the establishment of practical methods for mycotoxin decontamination. This study investigated the effects of citric acid (CA) and lactic acid (LA) on common trichothecene mycotoxins in feeds contaminated with Fusarium mycotoxins. Contaminated feed samples were processed either with 5% CA or 5% LA solutions in a ratio of 1:1.2 (w/v) for 5, 24, or 48 h, and analyzed for multiple mycotoxin metabolites using a liquid chromatography–tandem mass spectrometric method. The analyses showed that treating the feed with CA and LA lowered the concentration of deoxynivalenol (DON), whereby 5% LA lowered the original DON concentration in the contaminated feed samples by half, irrespective of the processing time. Similar lowering effects were observed for the concentrations of 15Ac-DON, 5-hydroxyculmorin, and sambucinol. The concentration of nivalenol was only lowered by the LA treatment. In contrast, CA and LA treatments showed no or only small effects on the concentration of several mycotoxins and their derivatives, including zearalenone, fumonisins, and culmorin. In conclusion, the present results indicate that the use of 5% solutions of LA and CA might reduce the concentration of common trichothecene mycotoxins, especially DON and its derivate 15Ac-DON. However, further research is required to determine the effect on overall toxicity and to identify the underlying mechanisms.