In situRuminal Crude Protein and Starch Degradation of Three Classes of Feedstuffs in Goats

Effect of Cereals and Legumes Processing on In Situ Rumen Protein Degradability: A Review

The determination of the ruminal degradability rate of feeds, mainly starch and crude protein, is one of the most common methods to evaluate the nutritional value of ruminant feed. The protein requirements for ruminants are met from microbial protein and undegraded dietary protein digested in the small intestine. In order to reach maximum productivity, high-quality proteins are needed, and the requirement for undegraded dietary protein increases with the performance of the animal. This protein can be supplied by reducing the ruminal degradation to increase the amount of protein digested post-rumen, but the form in which a feed is administered influences degradability, and grain processing, especially, is a common practice to improve feed efficiency. Despite these aspects, studies on the effects of feed processing methods on protein degradability are limited, even though more and more ruminants are fed with processed feeds. For these reasons, this review investigated the protein degradability of different processed cereals and legumes in ruminants based on the analysis of available literature in order to take stock of the state of the art on this topic. Results showed that: First, the majority of the papers are focused on the energy aspects mainly due to carbohydrate-rich feeds; second, the majority of the studies in the literature are quite old, probably because the changes occurred in the animal testing legislation that made in vivo studies more and more difficult in the last 20 years; third, as a consequence, the few data available in recent years concern in vitro experiments; fourth, we found a high variability of the experimental conditions thus affecting protein degradability and making it quite difficult to compare the different results.

Metabolic and Productive Response and Grazing Behavior of Lactating Dairy Cows Supplemented with High Moisture Maize or Cracked Wheat Grazing at Two Herbage Allowances in Spring

Simple Summary

Energy supplements such as high moisture maize or cracked wheat increase total dry matter intake (DMI) and dairy cow performance compared to pasture-only diets. However, the effectiveness of such a feeding strategy depends upon the level of herbage allowance (HA). In this study, increasing HA from 20 to 30 kg DM/cow had no effect on milk production but increased the concentration of urea in milk and plasma regardless of the type of energy supplement offered to grazing dairy cows. These results demonstrate that in high-quality pasture, low HA is appropriate to improve milk production performance per cow and per hectare.

Abstract

The aim was to determine the effect of the herbage allowance (HA) and supplement type (ST) on dry matter intake (DMI), milk production and composition, grazing behavior, rumen function, and blood metabolites of grazing dairy cows in the spring season. Experiment I: 64 Holstein Friesian dairy cows were distributed in a factorial design that tested two levels of daily HA (20 and 30 kg of dry matter (DM) per cow) and two ST (high moisture maize (HMM) and cracked wheat (CW)) distributed in two daily rations (3.5 kg DM/cow/day). Experiment II: four mid-lactation rumen cannulated cows, supplemented with either HMM or CW and managed with the two HAs, were distributed in a Latin square design of 4 × 4, for four 14-d periods to assess ruminal fermentation parameters. HA had no effect on milk production (averaging 23.6 kg/day) or milk fat and protein production (823 g/day and 800 g/day, respectively). Cows supplemented with CW had greater protein concentration (+1.2 g/kg). Herbage DMI averaged 14.17 kg DM/cow.day and total DMI averaged 17.67 kg DM/cow.day and did not differ between treatments. Grazing behavior activities (grazing, rumination, and idling times) and body condition score (BCS) were not affected by HA or ST. Milk and plasma urea concentration increased under the high HA (+0.68 mmol/L and +0.90 mmol/L, respectively). Cows supplemented with HMM had lower milk and plasma urea concentrations (0.72 mmol/L and 0.76 mmol/L less, respectively) and tended (p = 0.054) to have higher plasma β-hydroxybutyrate. Ruminal parameters did not differ between treatments.

Effect of Hybrid Rye and Maize Grain Processing on Ruminal and Postruminal Digestibility Parameters

The aim of the study was to determine the effect of the method of fragmentation of hybrid rye and maize grain on digestibility parameters for ruminants. Varying degrees of fragmentation – none (whole grains; WG), crushed (CG) or ground to pass through a 4.0 (GG4.0) or 1.5 mm (GG1.5) screen – were estimated by the in sacco nylon bag technique, in vitro true digestibility (IVTD), and the in vitro gas production (GP) technique. WG, CG, GG4.0 and GG1.5 were categorized as none, slight, moderate and extensive fragmentation of the grain kernel, respectively. Three non-lactating cows fitted with ruminal and duodenal cannulas were used to determine the effective rumen degradability (ERD) and intestinal and total tract digestibility (ID and TTD, respectively) of dry matter (DM), crude protein (CP) and starch. IVTD was determined with an ANKOM DaisyII Incubator, and GP and in vitro organic matter digestibility were determined with an ANKOMRF Gas Production System. Dry matter, CP and starch of hybrid rye grain were rapidly degraded in the rumen, and this degradability as well as ID and TTD was only marginally affected by the method of kernel fragmentation; however, among the methods used, the ERD of GG4.0 rye was the lowest. On the other hand, the greater the degree of kernel fragmentation, the higher ERD, ID and TTD were obtained for the DM, CP and starch of maize grain. In summary, rye grain is more susceptible to fermentation in the rumen than maize grain, but the means of grain processing may alter the rate, extent and site of their digestion, particularly for maize grain.

Synchronous feeding of liquid protein source with different grains on performance, digestibility, ruminal fermentation, blood metabolites, and carcass characters in growing lambs

The effects of feeding corn steep liquor (CSL; 420 g/kg crude protein, DM basis) along with different cereal grains on performance, digestibility, blood metabolites, ruminal fermentation, and carcass characters of growing lambs were evaluated. The constant amount of CSL was included in basal diet (100 g/kg, DM basis) and grain sources as experimental treatments were as follows: (1) corn grain (CG), (2) barley grain (BG), or (3) wheat grain (WG). The eighteen individually fed Farahani lambs averaging body weight 32 kg were allocated in completely randomized design (6 lambs/each) in a 9-week trial. The results showed that the greatest intake and gain were found in lambs fed CG in contrast to others. Nitrogen intake was constant among diets; however, the greatest nitrogen efficiency was found for corn grain-fed animals. Digestibility of nutrients were reduced in WG-fed animals in comparison with other grains. Ruminal proportions of propionate and butyrate were reduce in WG-fed lambs. The CG-fed animals displayed greater blood glucose and lower BUN concentrations compared with others. The greatest aspartate aminotransferase concentration as well as the greatest liver fat deposition suggested a dysfunction in liver performance in WG-fed animals. Except than that of a tendency for increment in dressing percentage in CG-fed lambs, no carcass character was differed among treatments. In conclusion, results revealed that feeding liquid protein source (CSL) is recommendable when it has been fed along with corn grain in comparison with barley or wheat grains in growing lambs.

Dietary starch source influences in growing goats: the intestinal losses of endogenous nitrogen and amino acids

Four goats (20 (SD2·5) kg) fitted with ruminal, duodenal and ileal cannulae were used in a 4 × 4 Latin square design to estimate the effects of a dietary starch source on the duodenal and ileal flows of endogenous N (EN) and endogenous amino acids (EAA) in growing goats. Goats were fed total mixed rations containing four starch sources (mainly from maize (MR), wheat (WR), paddy (PR) and sorghum (SR) treatments). There were no significant (P>0·05) effects of the dietary starch source on the intestinal flows of EN and EAA. The duodenal flows of EN were 2·40, 2·39, 2·18 and 1·56 g/d for the MR, WR, PR and SR treatments, respectively, as determined by the difference method, and the duodenal flows of EAA were 10·76, 11·29, 10·95 and 10·96 g/d by estimation with the amino acid profile method. The flows of EN and EAA at the ileum were 1·17, 1·12, 1·01, 0·70 and 4·87, 4·95, 4·94, 4·99 g/d, respectively, as estimated by the water-soluble method. The average intestinal reabsorption of EN and EAA was 57·5 %, and the endogenous Leu by the MR treatment was significantly (P < 0·05) lower than that of the other three treatments. The present results indicate that losses of endogenous protein in the intestine were not affected by the dietary starch source.