Abstract
Methods have been developed to measure the effectiveness of many roughages, but few evaluations have been conducted with tropical feeds. The objectives of this research were to determine the ...effectiveness of roughage sources based on bioassay and laboratory methods and identify the biological attributes of the diets that correlate with these methods. Six ruminally cannulated Nellore steers (408 ± 12 kg of BW) were randomly assigned to a 6 × 6 Latin square design within six diets: negative control diet (NC) with aNDF as 10% from corn silage (CS); positive control diet (PC) with aNDF as 20% from CS; and four diets containing 10% aNDF from CS and 10% aNDF from each of the following sources: sugarcane (SC), sugarcane bagasse (SCB), soybean hulls (SH), or low oil cottonseed hulls (LOCH). Physical effectiveness factor (pef, related to the physical characteristics of aNDF) and effectiveness factor (ef, related to the ruminal pH) were determined based on a linear model approach that uses a bioassay method in which CS aNDF was assumed to be the standard fiber source. Laboratory methods to estimate pef of roughage sources were based on the proportion of DM of roughage retained on a 1.18-mm sieve pef(>1.18 mm) or retained on the 8.0-mm Penn State Particle Separator screen pef(>8.0 mm). The pef calculated by the bioassay method (total chewing time and ruminal mat resistance) for CS, SCB, and SC were higher values (P < 0.05) compared with SH and LOCH. The pef(rumen mat) of SC and SCB were higher (P < 0.05) than that of CS, SH, and LOCH. The pef(rumen mat) of LOCH was 61% higher than SH. The ef(rumen pH) of SC and LOCH was higher (P < 0.05) than CS and SH. The pef(chewing, min/d), pef(chewing, min/kg of DM), pef(rumen mat), and ef(rumen pH) positively correlated with rumination time, total chewing time, and ruminal mat resistance (values from transit time in seconds). No correlation was observed (P > 0.05) between pef(>8.0 mm) and rumination time, chewing time, and ruminal pH. The pef calculated using the bioassay method as well as pef (>8.0 mm) were negatively correlated with rumen pH (P > 0.05). The values of the effectiveness of fiber sources obtained in this research can be used as a guideline for nutritionists aiming to replace roughage sources from tropical regions in beef cattle finishing diets. Under our conditions, the pef using the bioassay method or laboratory methods were not adequate in predicting ruminal pH.
•Oral stereotypies are often performed by cattle as a behavioral coping mechanism•Non-nutritive oral behaviors in cattle may be caused my limited access to roughage•Non-nutritive oral behaviors may ...be a behavioral signal of a welfare concern in cattle, but may also be a useful behavioral proxy for rumen status
Stereotypies are repetitive behaviors the may be performed in effort to relieve frustration or cope with a sub-optimal environment. Cattle are hypothesized to cope with the differences between forage and grain-based diets with oral stereotypies that manifest as in the form of non-nutritive oral behaviors (NNOB). Diets fed in confinement contain less roughage compared to the predominantly forage diets cattle consume while on pasture. These changes in diet composition, presentation, and time required to consume elicit physiological changes in the rumen and require cattle to spend less time engaged in oral behaviors (e.g. mastication of the cud, using the tongue to grasp and pull on grass) – all factors that contribute to NNOB performance. Allogrooming and self-grooming are also classified as NNOBs, however, they have function and are not stereotypic in nature. The purpose of this systematic review was to evaluate the current state of research regarding the relationship between diet and NNOB performance in cattle. Searches of CAB Abstracts, AGRIS, Scopus and SPAC, performed prior to September 2018 resulted in 22 articles (25 studies) that analyzed the impact of dietary treatments on NNOB performance in both beef and dairy cattle housed in confinement. Increasing dietary roughage levels decreased the performance of NNOBs while limiting dietary roughage increased NNOB performance. However, there was little conclusive evidence to suggest that ingredient type, particle size, total feed amount, mode of feeding, or mineral addition influenced NNOB performance. Strengths of the studies included consistent housing across treatments and valid and reliable methods of behavioral recording. Many studies did not consider weaning method in their animal selection and some studies did not randomize animals into each treatment, identifying an opportunity for improvement in this area of research. Risk of bias was performed using JBI Critical Assessment Tools and a very low risk of bias was found for both randomized and (non-random) quasi-experiment trials. This systematic review examined studies varying in sample size, cattle age/sex and experimental design, showcasing a small yet diverse research area.
•Decreasing levels of rNDF up to 7 % in diets with high inclusion of corn DDGS improved dry matter intake and ADG.•Decreasing levels of rNDF down to 4 % did not cause acidosis in diets with high ...inclusion of DDGS.•Decreasing levels of rNDF changed the consumption pattern of the diet in favor of longer particles.
This study evaluated decreasing levels of roughage NDF (10, 7, and 4 % in DM) in DDGS-based finishing diets. In experiment 1, growth performance, feeding behavior, and carcass characteristics were evaluated on 18 Nellore bulls blocked by initial body weight (BW), with 6 replicates per treatment, in a complete randomized block design. In experiment 2, digestibility, feeding behavior, and ruminal fermentation were evaluated on 6 Zebu crossbred steers in two, 3 × 3 Latin square designs. Differences were considered significant at P < 0.05 and trends were declared at P < 0.10. In experiment 1, DMI increased quadratically with decreasing roughage NDF (rNDF) with the greatest DMI value achieved at 7.43 % rNDF (P<0.01). Average daily gain tended to respond quadratically, with the greatest estimated value occurring at 7.23 % rNDF (P<0.09). Similarly, hot carcass weight and final BW tended to respond quadratically (P<0.09). No effects of roughage NDF level were observed on carcass dressing percentage. Animals that received the lowest dietary rNDF selected for particles longer than 8 mm (P<0.05). Increasing roughage NDF levels in the diet tended to increase time spent ruminating (P<0.06). In experiment 2, a greater inclusion level of rNDF did not affect DMI, but linearly increased NDF intake (P<0.01) and tended to decrease DM digestibility (P<0.09). Ruminal pH remained, on average, above 6. Ruminal ammonia-nitrogen increased up to an inclusion level of 6.6 % rNDF and then decreased (P<0.02). Acetate: propionate ratio linearly decreased with increasing levels of dietary roughage NDF (P<0.02). Decreasing roughage NDF inclusion level in diets with high levels of corn DDGS is viable without compromising performance or increasing the risk of ruminal acidosis occurrence. Diets containing between 7.23 % and 7.43 % of roughage NDF are proposed to be suitable when corn DDGS-based diets are used to maximize intake and weight gain.
Abstract
This study evaluated impacts of feeding a finishing diet throughout both the receiving and finishing period compared to a receiving diet with adaptation to the finishing diet on health, ...performance, ruminal pH, and rumination of high-risk feedlot cattle. Five truck-load blocks of steers and bulls (n = 400) were used in a generalized complete block design and assigned to receive: 1) finishing diet for the entire feeding period (FIN) or 2) receiving diet for the first 56 d, followed by transition to the finishing diet (REC). All cattle were consuming the same diet on d 74. A subset of cattle (n = 48) were randomly selected to quantify ruminal pH, temperature, and rumination time. Ultrasounds were completed on d 0, 74, and 146 to determine fat thickness. Cattle fed REC had greater (treatment × day; P < 0.01) DMI from d 1 to 67 but less DMI from d 74 to 82, and DMI did not differ from d 83 to 174. Energy intake (treatment × day; P < 0.01) was greater for FIN from d 14 to 75. Cattle consuming FIN had greater (P ≤ 0.01) ADG and BW and improved (P < 0.01) gain:feed from day 0 to 74. At d 174, BW of FIN was 9.6 kg greater (P = 0.02). On d 74, FIN had greater (P ≤ 0.05) fat thickness but did not differ (P ≥ 0.61) at d 146. There was no difference (P ≥ 0.31) in health outcomes. Ruminal pH (treatment × day; P < 0.01) was greater for FIN on d 2 and 61, and rumination time was less (P < 0.01) for FIN from d 0 to 28. Overall, these results suggest providing a finishing diet to high-risk calves upon arrival may be a viable alternative to a traditional receiving diet.
Abstract
The rotary crusher allows you to qualitatively grind pressed roughage. The authors proposed and developed an improved technological scheme of an impact crusher equipped with two beaters for ...dosed transfer to the grinding chamber. The impact crusher consists of a transfer chute, metering beaters, a chopping chamber, a rotor, chopping knives, fixed knives, an exit chute, a feed bin and an electric motor. The efficiency of work is determined by the following parameters: length, width and thickness of knives, rotor speed. The purpose of the work is to substantiate the parameters of the rotor and its knives. Analytical dependencies are obtained to determine the parameters of the knife. Theoretical studies have established that the minimum length of the knife should be 6.9 cm, the width of the knife is 50 mm, and its thickness is 4 mm. A model for the theoretical calculation of the probability of grinding roughage of the required size within the limits of zootechnical requirements has been obtained. Based on the calculations, the probability of cutting the feed of the required size, depending on the number of rotation of the rotors, was established.
•The effect of inclusion of açai seed as a fiber source in high-concentrate diets fed to beef cattle was explored.•Açai seed increased the intake of DM, OM, CP, ME, and NDF.•Açai seed did not alter ...the ruminal and total digestibility of DM and nutrients.•Açai seed increased rumen acetate and the pH remained above 6.16.•Açai seed did not affect ruminal kinetics and nitrogen use in the diet.
This study evaluated the effects of different levels of inclusion of coarsely broken açai seed (CBAS) in the diet of feedlot beef cattle on the intake, digestibility, ruminal degradation, passage kinetics, and nitrogen utilization efficiency. Five ruminally fistulated crossbred bulls (387±27kg body weight) were used in a 5×5 Latin square design. A total mixed ration with 750g/kg concentrate and 250g/kg roughage, based on the total dry matter (DM), was used. The treatments consisted of the inclusion of CBAS at 0, 50, 100, 150, and 200g/kg DM as a fiber source in the diet. The roughage used was Mombasa grass silage, which was partially replaced by CBAS. A linear increase in organic matter (OM; P=0.042), crude protein (CP; P=0.023), and neutral detergent fiber (NDF; P=0.022) intake was observed with the inclusion of CBAS in the diet, while a linearly increasing trend was observed for DM (P=0.077) and metabolizable energy (ME; P=0.051) intake. The total, ruminal, and intestinal digestibility of DM and nutrients were not affected by the inclusion of CBAS (P > 0.10). Ruminal ammonia nitrogen decreased linearly (P=0.045), while acetate concentration showed a linear increase (P=0.038), propionate was not affected (P=0.762), and butyrate showed a linear tendency to increase (P=0.086) with the inclusion of CBAS. Passage rate and DM degradation, as well as N utilization were not affected by the inclusion of CBAS (P > 0.10), except for N fecal excretion that showed a linear tendency to increase (P=0.092). Thus, we conclude that CBAS increases organic matter, crude protein, metabolizable energy, and neutral detergent fiber intake in high-concentrate diets without compromising rumen kinetics and nitrogen utilization in beef cattle. Therefore, the CBAS can be considered as an alternative roughage source in scenarios where forage silage of low quality is the fiber source.
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