Effect of grinding or pelleting high grain maize- or barley-based concentrates on rumen environment and microbiota of beef cattle

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.

Effects of conditioner retention time during pelleting of starter feed on nutrient digestibility, ruminal fermentation, blood metabolites, and performance of Holstein female dairy calves

This study evaluated the effects of conditioner retention time during the pelleting process of starter feed on intake, nutrient digestibility, ruminal fermentation, blood metabolites, and growth performance of dairy calves. A total of 30 Holstein female dairy calves [40 ± 1.93 kg of body weight (BW)] were randomly assigned to 1 of 3 treatments: (1) pelleted starter conditioned for 0 min (CON), (2) pelleted starter conditioned for 2 min, and (3) pelleted starter conditioned for 4 min. Three pelleted starter feeds had similar nutritional composition, and the starters were blended with 3% chopped wheat straw and fed to individually housed calves from d 3 to 70 of age. All calves were fed 4 L/d of pasteurized whole milk twice daily at 0800 and 1600 h from d 3 to 50 of calf age, followed by 2 L/d of morning feeding from 51 to 56 d of age. All calves were weaned on d 56 of age and remained in the study until d 70 of age. With the increase of conditioner retention time during pellet processing for 0, 2, and 4 min, the gelatinized starch content of pelleted starter feed linearly increased from 14, 30, and 45%, respectively. Additionally, the pellet durability and hardness also linearly increased with increasing conditioner retention time during pelleting. Feeding pelleted feed prepared using different conditioner retention time did not affect feed dry matter intake, metabolizable energy intake, weaning BW, final BW, or feed efficiency during the study. We observed no differences in the total-tract apparent digestibility of organic matter, neutral detergent fiber, and crude protein around weaning (d 49 to 56 of age) and after weaning (d 63 to 70 of calf cage); however, the digestibility of dry matter and starch after weaning was increased with increasing conditioner retention time during pelleting of starter feed. No difference was found in overall average daily gain (ADG) or growth rates of hip height, withers height, and heart girth. Ruminal volatile fatty acid profile was not affected by pelleting under different conditioner retention times. The ruminal ammonia concentration tended to be lower for calves fed the 4-min diet compared with those fed the CON diet during the postweaning period. The postweaning (d 57-70 of age) ADG was greater for calves fed the 4-min diet compared with those fed the CON diet. In conclusion, the conditioning time during the pelleting process of starter feed increased the gelatinization of starch, durability, and hardness of the pellets but did not influence feed intake, feed efficiency, and skeletal growth during the first 70 d of age. Increasing conditioning time during the pelleting process improved postweaning ADG; however, the final BW of calves was similar among treatments.

Feeding Complete Concentrate Pellets Containing Ground Grains or Blend of Steam-Flaked Grains and Other Concentrate Ingredients in Ruminant Nutrition – A Review

The feed industry has attempted to encourage the animal husbandry sector to feed complete concentrate pellets containing ground grains in ruminant nutrition and thus prevent farmers from making concentrate in their farms. Reducing particle size using pre-pelleting grinding and pressing materials during pellet formation, plus starch gelatinization by heat treatment in the conditioner are key factors determining the extent and rate of starch digestion in ingested pellets. If prepelleting grinding of corn and barley grain for using in the pelleted concentrate results in ground materials of less than 1.8 mm mean particle size (especially in the case of barley grain which is highly fermentable), then it increases the rate of fermentability in the rumen which in turn increases the acidosis risk. Such situation and dissatisfaction from pellets feeding to ruminant have directed farmers to produce homemade mash concentrate which may include steam-flaked form of grains in the concentrate mixture. Pelleting process increases the time needed to collapse the pellet in the rumen so delays the access of microbes to fermentable organic matter. This counterbalance property highly depends on pellet size with highest effect obtained using 10 mm diameter pellets for cattle. Feeding separately steam-flaked grains (plus other pelleted/mash non-grain ingredients of concentrate) may give results similar to the complete concentrate pellets having ground grains prepared according to optimized recommendations (pellet diameter and grain mean particle size). Nonetheless cost benefit studies are necessary to adopt one of the above two optimized technologies that has higher starch utilization and lower fecal starch excretion by animal. In the situation where consuming steam-flaked grains has priority of application in the diet, it is strongly recommended to pellet non-grain portions of concentrate for obtaining numerous pellet advantages such as reducing transportation cost, dust, sorting and bird removal.

Effect of preweaning diet on performance, blood metabolites and rumen fermentation around weaning in calves of two beef breeds

Context Good transition from suckling to high-concentrate diets is essential to avoid nutritional disorders during the fattening period of beef calves. Aims Assessing the optimal feeding strategies during the preweaning period of beef calves for an adequate adaptation to high-concentrate diets. Methods A total of 30 female beef calves (15 Parda de Montaña and 15 Pirenaica), managed under restricted suckling, were assigned to three preweaning diets (milk only [MO], milk plus hay [MH], milk plus concentrate [MC]), fed from the third month until weaning at 5 months. During the subsequent transition period (1 month), all animals received a fattening concentrate plus wheat straw ad libitum. Key results Milk intake did not differ among diets; solids intake was similar for MH and MC calves. Preweaning supplementation improved performance at the end of the suckling period (MC > MH > MO). During transition, concentrate intake was lower for MO calves; MH calves showed the lowest feed efficiency. At the end of transition, MC calves showed the highest liveweight and average daily gain (MC > MH = MO). Rumen pH at weaning did not differ from that at the end of transition in MC calves, whereas MH and MO animals showed lower values at the latter. Supplemented calves showed higher volatile fatty acids concentration than MO calves at weaning; MC calves showed the lowest values at the end of the transition period. Ammonia and lactic acid concentration at weaning was the highest for MO and MC calves respectively, with no differences between diets at the end of transition. Glucose and non-esterified fatty acids concentrations were only affected by age; urea and β-hydroxybutyrate were affected by the interaction between diet and age. Economic profitability at weaning was higher for supplemented calves (MH = MC > MO), and ranked MC > MO > MH at the end of the transition. Gains during the suckling period, and hence the economic margin, were higher for Parda de Montaña than for Pirenaica calves; during transition the economic margin was similar. Conclusions Preweaning supplementation with concentrates is the most interesting option in terms of performance and profitability. Implications Preweaning solid supplementation increases calf performance and provides better rumen development, essential for a smooth transition to fattening diets.

Grain grinding size of cereals in complete pelleted diets for growing lambs: Effects on animal performance, carcass and meat quality traits

The main goal of the present study was to clarify the effects of different grinding particle size of grains (2-mm vs. 6-mm) included in complete pelleted diets (CPD) for fattening lambs on animal performance, carcass and meat quality. Twenty male merino lambs (14.8 kg; n = 10 per group) were fed the corresponding diet ad libitum and slaughtered when they reached 27 kg. No differences were observed in the feed conversion ratio or carcass characteristics. However, lambs fed coarser diets (6 mm) were more efficient with less residual feed intake (-14.0 vs. 15.4 g DM/animal/d; P < .05) than lambs fed the 2 mm CPD. Lambs fed the 6-mm CPD showed higher levels of intramuscular fat and saturated fatty acids. Consequently, increasing the particle size of the grains included in CPD allows for improving feed efficiency and intramuscular fat in fattening lambs.

The effect of pelleting on in situ rumen degradability of compound feed containing brown rice for dairy cows

This study was conducted to determine the effect of pelleting on in situ dry matter degradability of pelleted compound feed containing brown rice for dairy cows. Mash feed of the same composition was used as a control and the in situ study was conducted using three non-lactating Holstein steers fitted with a rumen cannula. The feeds contained 32.3% brown rice, 19.4% rapeseed meal, 11.4% wheat bran and 10.6% soybean meal (fresh weight basis). Except for moisture content, the chemical composition of the feed was not affected by pelleting. In situ dry matter disappearance of the feed increased from 0 to 2 h and after 72 h of incubation with pellet processing. Integration of the dry matter disappearance values over time revealed that degradability parameter a (soluble fraction) increased with pellet processing, whereas parameter b (potentially degradable fraction) decreased. Parameter c (fractional rate of degradation) and effective degradability (5% passage rate) were not affected by pellet processing. We concluded that pellet processing promotes rumen degradability at early incubation hours when the pelleted feed contains brown rice.

Effect of dietary starch level and its rumen degradability on lamb meat fatty acid composition

Forty lambs were fed one of four diets supplemented with a linseed and sunflower oil blend but differing in starch level (mid, ≈35 vs. high, ≈50%) and starch rumen degradability (mid, ≈70 vs. high, ≈80%). The effects of diet on growth, carcass traits and meat fatty acid (FA) composition, with emphasis on biohydrogenation intermediates were evaluated. Lambs stayed on trial for 5weeks until slaughter. Treatment had no effect on animal performance and carcass traits. High-degradability diets decreased (P=0.04) meat shear force compared with mid-degradability diets. Lipid content of meat was unaffected by the diet. Mid-starch diets increased (P<0.05) the saturated FA and cis-MUFA but decreased (P<0.05) the trans-MUFA, particularly the t10-18:1, when compared with high-starch diets. The t11-18:1 (0.7% of total FA) and c9,t11-18:2 (<0.3%) remained low and the 18:3n-3 remained high (1.74%) and unaffected by diet.