Comparative study of feeding and rumination behaviour of goats and sheep fed mixed grass hay of different chop length.

Rumination is reported to be more pronounced in sheep compared to goats. This study compared the feeding and rumination behaviour of small ruminants and consisted of two experiments (E1 and E2). In E1, four sheep and four goats were offered low-quality hay (NDFom: 692 g/kg dry matter [DM]), processed to two chop lengths (long hay [LH]: 35 mm; short hay [SH]: 7 mm) in a 2 × 2 factorial (2 species × 2 chop lengths), cross-over design. In E2, the same animals were offered moderate-quality hay (NDFom: 636 g/kg DM) processed as LH and SH. Hay was offered for ad libitum consumption. Feeding and rumination behaviour was evaluated using video recordings. Aspects of rumination like chewing frequency were evaluated for 30 min per day. Faecal samples were analysed for faecal-N and particle size. There was no species effect on feed intake and organic matter digestibility (faecal N as proxy); however, goats consumed more LH than SH in E1 and E2. There was an effect of species on rumination:eating duration (R:E) ratio (higher in sheep) in E1 but not in E2, where there was a tendency for a species effect on rumination duration. In E1 and E2, sheep had a higher R:E ratio for SH than for LH. For rumination behaviour, there was a species effect for number of daily boli, chewing frequency and chews per day (more in sheep) in E1 and E2. No effect of species was found for faecal particle size. Despite much concordance, feed comminution behaviour differed in some aspects between sheep and goats. In an evolutionary context, a shift of significance of rumination could be triggered by a higher amount of abrasives in natural diets of sheep, rendering a shift of chewing towards ruminally prewashed material a rewarding strategy.

Replacing soybean hulls with grass hay on growth, intake, total tract digestibility, and rumen microbial nitrogen production of weaned Holstein dairy calves from 8 to 16 weeks of age.

The objective of this experiment was to determine the effects of replacing soybean hull (SBH) pellets with grass hay (GH) on growth, intake, total-tract digestibility, and rumen microbial nitrogen production of weaned dairy calves from 8 to 16 wk of age. Holstein calves (n = 16) were randomly assigned to 1 of 4 rations containing, on a dry matter (DM) basis, 76% grower with the remaining 24% being made up of different amounts of SBH pellets and GH [0% GH, 24% SBH (0GH); 8% GH, 16% SBH (8GH); 16% GH, 8% SBH (16GH); and 24% GH, 0% SBH (24GH)]. Calves were weaned at 6 wk, housed individually, and studied from 8 to 16 wk of age. From 8 to 9 wk of age calves were offered a ration consisting of 50% of texturized starter (20% CP and 35% starch), which was offered from 3 d of age, and 50% of their assigned ration. From 9 wk until the end of the study, calves were offered 100% of their assigned ration. Intake and body weight were measured weekly, and frame measurements were taken at the beginning and end of the study. Animal behavior observations were recorded every 5 min over a 24-h period at 10 and 14 wk of age. Total fecal and urine collection was conducted for 4 d consecutively at 11 and 15 wk of age. Feed and feces were evaluated for DM, N, neutral detergent fiber, acid detergent fiber, and starch to determine total-tract digestibility. Feces were evaluated for geometric mean particle length (Xgm) and particle size distribution. Urine was evaluated for N, creatinine, urea, and total purine derivatives to estimate microbial N yield. Calves offered 0GH and 8GH had a 20% increase in intake, average daily gain (1.23, 1.27, 0.89, and 0.71 kg/d for 0GH, 8GH, 16GH, and 24GH, respectively), and feed efficiency compared with 16GH and 24GH. Calves offered 8GH had the greatest levels of neutral detergent fiber and acid detergent fiber digestibility, as well as the greatest estimated microbial N yields. Inclusion of forage increased rumination time (2.75, 6.89, 7.18, and 8.16 h/d for 0GH, 8GH, 16GH, and 24GH, respectively) and decreased fecal Xgm by ~35% compared with calves offered 0GH. In the current study, increasing the replacement of SBH with GH beyond 8% was detrimental to weaned calf performance. These results indicate that when diets containing 8% GH and 16% SBH were fed to recently weaned calves, rumen functionality and feed efficiency were optimized compared with the other GH-SBH combinations.

Increasing grass hay inclusion level on weaned dairy calf growth, intake, digestibility, and ruminal fermentation.

The objective was to determine effects of increasing grass hay (GH) inclusion level on weaned dairy calf growth, intake, digestibility, and ruminal fermentation. Holstein calves (n = 45) were randomly assigned to 1 of 3 total mixed rations with increasing GH [10, 17.5, or 25% on a dry matter (DM) basis; LGH, MGH, or HGH, respectively]. Calves were weaned at 6 wk of age, housed individually, and studied from 7 to 16 wk of age. Rations, consisting of texturized calf starter (20% crude protein) and coarsely chopped GH, were offered ad libitum as separate components from 7 to 9 wk of age. After 9 wk, feed was offered as a total mixed ration containing the assigned level of GH and fed according to the clean bunk feeding strategy as a means of limiting refusals. Initial 9-wk body weight was 81.6 ± 9 kg (mean ± standard deviation). Intake and growth were measured weekly. Blood samples were collected at 9, 10, 12, 14, and 16 wk of age for analysis of plasma glucose and ß-hydroxybutyrate. Total fecal collection (12 calves; 4 per treatment) was conducted at 11 and 15 wk of age for 4 d consecutively. Rumen samples were collected over the final 24 h of each fecal collection period to evaluate pH and volatile fatty acid profile. Feeds and feces were evaluated for DM, neutral detergent fiber, acid detergent fiber, and starch to estimate total-tract digestibility. Intake and weight gain were analyzed from 7 to 9 wk and 9 to 16 wk, representing pretreatment and treatment periods. No differences were observed between treatments from 7 to 9 wk. However, differences were found from 9 to 16 wk. Final body weight, average daily gain, DM intake, and metabolizable energy intake all decreased with increased GH. However, skeletal frame measurements did not vary between treatments. Plasma ß-hydroxybutyrate tended to decrease with increased GH. No differences were observed in DM or starch digestibility, but neutral detergent fiber and acid detergent fiber digestibility increased with increased GH. Mean rumen pH and total volatile fatty acid did not change with increasing GH inclusion; however, there was an interaction with time indicating that ruminal fermentation patterns throughout the day were different for calves offered MGH and HGH versus those offered LGH. These results indicate that feeding levels of GH >10% reduce growth and intake before 16 wk and alter ruminal fermentation patterns.

Effect of diet quality and shearing on feed and water intake, in vitro ruminal methane production, and blood parameters of Omani sheep.

The aim of this study was to evaluate the effect of diet and animal shearing on the feed and nutrient intakes, water intake, in vitro ruminal methane production, and blood parameters of Omani sheep. A pens trial was carried out for 16 days each in March and June of 2017 using 20 Omani non-castrated yearling rams selected from the sheep herd in the research station and randomly assigned to four groups with 5 animals per group. Group 1: sheared animals fed a high concentrate (HC) diet, group 2: fleeced animals fed a HC diet, group 3: sheared animals fed a low concentrate (LC) diet, group 4: fleeced animals fed a LC diet. Furthermore, a metabolic crates trial was carried out in July of 2017 on three animals from each group over a 10-day period. The effect of diet and shearing on the tested parameters was evaluated using the mixed linear model, where animals were fitted as a random effect to account for the individual animal deviation from the overall mean. Results showed that rams fed on the high concentrate diet had a significantly increased organic matter intake of the total diet (62 g/kg 0.75 Live Weight (LW) in HC group to 54 g/kg 0.75 LW in LC group), an increased water intake (6.3 L/day vs 4.8 L/day in LC group), and a reduced in vitro methane production (i.e. the invitro ruminal CH4 was measured and converted to daily CH4 using the daily feed intake data and was 20.4 g CH4 per head/day in HC group vs 27.3 g CH4 per head/day in LC group), compared with rams fed on the low concentrate diet. Furthermore, shearing had a significant effect (P < 0.01) on increased feed and nutrients intake. The apparent and organic matter digestibility was significantly different (P < 0.01) between the experimental groups and was greater for those rams fed on the HC diet. Partial substitution of low-quality Rhodes grass hay by high-quality concentrate significantly improved the total diet organic matter digestibility (P < 0.01) and nutrients digestibility, whereas no significant effects on biochemical blood parameters or animal health were observed. These results show the importance of utilizing effective feeding and shearing plans to improve the productivity and reduce the methane emission of Omani sheep.

Production performance, nutrient digestibility, and milk fatty acid profile of lactating dairy cows fed corn silage- or sorghum silage-based diets with and without xylanase supplementation.

The objective of this study was to evaluate the effects of supplementing xylanase on production performance, nutrient digestibility, and milk fatty acid profile in high-producing dairy cows consuming corn silage- or sorghum silage-based diets. Conventional corn (80,000 seeds/ha) and brown midrib forage sorghum (250,000 seeds/ha) were planted, harvested [34 and 32% of dry matter (DM), respectively], and ensiled for more than 10 mo. Four primiparous and 20 multiparous Holstein cows were randomly assigned to 1 of 4 diets in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments and 19-d periods. Treatment diets consisted of (1) corn silage-based diet without xylanase, (2) corn silage-based diet with xylanase, (3) sorghum silage-based diet without xylanase, and (4) sorghum silage-based diet with xylanase. The xylanase product was supplemented at a rate of 1.5 g of product/kg of total DM. Corn silage had higher concentrations of starch (31.2 vs. 29.2%), slightly higher concentrations of crude protein (7.1 vs. 6.8%) and fat (3.7 vs. 3.2%), and lower concentrations of neutral detergent fiber (36.4 vs. 49.0%) and lignin (2.1 vs. 5.7%) than sorghum silage. Xylanase supplementation did not affect DM intake, milk yield, milk fat percentage and yield, milk protein percentage and yield, lactose percentage and yield, and 3.5% fat-corrected milk yield. Cows consuming corn silage-based diets consumed 13% more DM (28.8 vs. 25.5 kg/d) and produced 5% more milk (51.6 vs. 48.9 kg/d) than cows consuming sorghum silage-based diets. Milk from cows consuming sorghum silage-based diets had 16% greater fat concentrations (3.84 and 3.30%) than milk from cows consuming corn silage-based diets. This resulted in 8% greater fat yields (1.81 vs. 1.68 kg/d). Silage type did not affect milk protein and lactose concentrations. Xylanase supplementation did not affect nutrient digestibility. Cows consuming corn silage-based diets showed greater DM (77.3 vs. 73.5%), crude protein (78.0 vs. 72.4), and starch (99.2 vs. 96.5%) digestibilities than cows consuming sorghum silage-based diets. In conclusion, xylanase supplementation did not improve production performance when high-producing dairy cows were fed corn silage- or sorghum silage-based diets. In addition, production performance can be sustained by feeding sorghum silage in replacement of corn silage.

Effect of supplementation of indigenous browse tree pods on weight gain and carcass parameters of Abergelle rams.

The objective of the study was to evaluate the effect of supplementation of indigenous browse tree pods on nutrient intake, digestibility, weight gain, and carcass parameters of local Abergelle rams fed grass hay as a basal diet. This experiment was conducted at the Abergelle Agricultural Research Center farm in Tigray region, northern Ethiopia. Experimental rams were grouped according to their initial body weight (17.4 ± 0.95 kg) in a randomized complete block design into three treatments and six replications. Treatments consisted of feeding grass hay free of choice supplemented with pods of either Acacia tortilis (T1), Faidherbia albida (T2), or Dichrostachys cinerea (T3) fed at the rate of 10 g kg-1 body weight daily. The crude protein (CP) contents of the supplemental feeds in T1, T2, and T3 were 167, 156, and 135 g kg-1 dry matter (DM), respectively. The CP intake was significantly higher (P < 0.05) in T1 and T2 than that in T3. No statistical difference (P > 0.05) was observed in the digestibilities of DM and CP. Final body weight, average daily gain, slaughter weight (SW), hot carcass weight, and ribeye area were not significantly different (P > 0.05) among the treatments. However, dressing percentage based on SW in T1 and T2 was significantly higher (P < 0.05) than that in T3. Therefore, from this research, it can be concluded that though the weight gains and carcass weights of experimental rams were not as such remarkable among the treatments, efficient utilization of locally available and cheap browse tree pods as alternative protein supplements to Abergelle sheep during the dry season could be important to small holder farmers.

Interactions of corn meal or molasses with a soybean-sunflower meal mix or flaxseed meal on production, milk fatty acid composition, and nutrient utilization in dairy cows fed grass hay-based diets.

We investigated the interactions of corn meal or molasses [nonstructural carbohydrate (NSC) supplements] with a soybean-sunflower meal mix or flaxseed meal [rumen-degradable protein (RDP) supplements] on animal production, milk fatty acids profile, and nutrient utilization in dairy cows fed grass hay diets. Eight multiparous and 8 primiparous Jersey cows averaging 135±49d in milk and 386±61kg of body weight in the beginning of the study were randomly assigned to 4 replicated 4×4 Latin squares with a 2×2 factorial arrangement of treatments. Each period lasted 19d with 14d for diet adaptation and 5d for data and sample collection. Cows were fed diets composed of mixed-mostly grass hay plus 1 of the following 4 concentrate blends: (1) corn meal plus a protein mix containing soybean meal and sunflower meal; (2) corn meal plus flaxseed meal; (3) liquid molasses plus a protein mix containing soybean meal and sunflower meal; or (4) liquid molasses plus flaxseed meal. Data were analyzed for main effects of NSC and RDP supplements, and the NSC × RDP supplement interactions. Significant NSC × RDP supplement interactions were observed for milk urea N, milk N efficiency, and the sums of milk saturated, monounsaturated, and polyunsaturated fatty acids. No effect of NSC supplements was observed for nutrient intake and milk yield. However, 4% fat-corrected milk (-0.70kg/d) and energy-corrected milk (-0.60kg/d) were significantly reduced in cows fed liquid molasses due to a trend to decreased concentration of milk fat (-0.17%). Diets with liquid molasses resulted in increased (+35%) concentration and yield of milk enterolactone, indicating that this mammalian lignan can be modulated by supplements with different NSC profiles. Overall, NSC and RDP supplements profoundly changed the milk fatty acid profile, likely because of differences in fatty acids intake, Δ(9)-desaturase indices, and ruminal biohydrogenation pathways. Feeding liquid molasses significantly reduced plasma urea N (-1.2mg/dL), urinary N excretion (-20g/d), and N digestibility (-3.2 percentage units). Flaxseed meal significantly reduced yields of milk (-1.3kg/d), milk fat (-90g/d), and milk lactose (-60g/d), but significantly increased the concentration and yield of milk enterolactone. Further research is needed to elucidate the negative responses of flaxseed meal on yields of milk and milk components.

Effects of protein grass hay as alternative feed resource on lamb's fattening performance and meat quality.

Protein grass hay (PGH) was used as a new feed source for lambs to study its effect on fattening performance and meat quality. Fifty-six male lambs were allotted to four experimental groups and fed for eight weeks either alfalfa hay (AH)-based diet (control) or diets in which AH was replaced with 33 %, 66 %, or 99 % PGH. The inclusion of PGH did not affect final body weight, dry matter intake, average daily gain, feed conversion ratio, or carcass weight. Moreover, substituting AH with PGH at any level did not influence the ruminal fermentation or serum biochemical parameters, meat color, water holding capacity, shear force, or amino acid profile. However, relative liver weight was increased with 66 % substitutions. Furthermore, replacing 99 % AH with PGH decreased the meat's pH at 24 h. Higher levels of C18:3n-3, C20:5n-3, and total n-3 PUFA and a lower ratio of n-6: n-3 PUFA were also observed in meat from lambs fed PGH at 99 %. These findings suggest that PGH could be incorporated into the lamb's diet up to 99 % without compromising fattening performance and body health while improving their meat n-3 PUFA deposition.

Getting clues from nature: the impact of grass hay on suckling piglets' gastrointestinal growth and colonic microbiota.

Introduction: The effect of dietary fiber on pig production has been extensively evaluated. Inspired by observations of the diet of wild, young piglets, this study aimed to examine the possibility of feeding grass hay to suckling piglets besides concentrated creep feed. Methods: The sow-nursed piglets in this study were divided into two groups based on balanced sow parities. The control group (CON, n = 7 sows) only received a regular, concentrated creep feed, while the treatment piglets (GH, n = 8 sows) were also provided with chopped grass hay from 2 days of age until weaning (28 days). At weaning, one piglet with a median weight was selected from each litter for post-mortem evaluation. Subsequently, six pigs around median weight per sow were grouped into nursery pens and monitored for their feed intake and body weight gain until 9 weeks of age. Results and discussion: Piglets in GH consumed, on average, 57 g of grass hay per piglet during the entire lactation period. The emptied weight of the small and large intestine was significantly greater in GH (280 vs. 228 g, 88.8 vs. 79.3 g, respectively, p < 0.05), and the length of the large intestine was stimulated by the grass hay (164 vs. 150 cm, p < 0.05). Morphologically, the villus height in the jejunum was higher in GH (p < 0.05). In the large intestine, the crypt depth of the mid-colon was lower in GH. Moreover, the short-chain fatty acid (SCFA) concentrations in the cecum were increased in GH compared to CON (1,179 vs. 948 µmol/g dry matter, p < 0.05), whereas in the colon, SCFA concentrations were lower in CON (341 vs. 278 µmol/g dry matter, p < 0.05). There was no major impact of grass hay inclusion on the colonic microbiota composition. Only a trend was observed for a lower inverse of the classical Simpson (InvSimpon) index and a higher abundance of Lactobacillus genera in GH. After weaning, no significant differences in feed intake and body weight gain were observed. In conclusion, supplementing the grass hay to suckling piglets led to alterations in intestinal morphology, increased SCFA fermentation in proximal sections of large intestine, stimulation of gastrointestinal tract growth, and subtle modifications in colonic microbiota.

Longitudinal Investigation of the Native Grass Hay from Storage to Market Reveals Mycotoxin-Associated Fungi.

This study aimed to characterize the fungal diversity and mycotoxin concentrations of native grass hay in various storage periods. In the present study, the native grass hay samples were collected when stored for 0 d (D0 group), 30 d (D30 group), and 150 d (D150 group), respectively. Here, mycotoxin analyses combined with ITS gene sequence were performed to reveal the changes in response to the storage period. There were notable differences in deoxynivalenol and aflatoxin B1 concentrations among the three groups. Compared to the D150 group, the diversity of the fungal community was higher in the D0 and D30 groups, which indicating the diversity was significantly influenced by the storage period. No significant (p > 0.05) difference was observed among the three groups on the dominant phyla. Interestingly, a significant (p < 0.05) difference was also observed in Chactomella and Aspergillus among the three groups, the abundance of the Chactomella was significantly (p < 0.05) decreased and the abundance of Aspergillus was statistically (p < 0.05) increased in the D150 group. Correlation analysis of the association of fungi with mycotoxin could provide a comprehensive understanding of the structure and function of the fungal community. These results indicated that the good practices of storage are essential for the prevention of mycotoxin. The information contained in the present study is vital for the further development of strategies for hay storage with high quality in the harsh Mongolian Plateau ecosystem.

Evidence of a novel cross-species transmission by ovine papillomaviruses.

Ovine papillomavirus (OaPV) comprises four genotypes; OaPV1, OaPV2 and OaPV4 are fibropapillomaviruses within the genus Deltapapillomavirus, whereas OaPV3 is an epitheliotropic virus that belongs to the genus Dyokappapapillomavirus. To date, all of them have been known to infect sheep only. OaPV1, OaPV2 and OaPV4 have been associated with ovine cutaneous and mucosal fibropapillomas, whereas OaPV3 is a key factor in the squamous cell carcinoma pathway of the sheep skin. Whole blood samples obtained from 128 cattle at public slaughterhouses were investigated using droplet digital polymerase chain reaction (ddPCR). ddPCR is a new-generation PCR technique that enables an accurate and absolute quantification of target molecules with high sensitivity and specificity. All OaPVs were detected by identification and quantification of nucleic acids using specific fluorescent probes. Of 128 blood samples, 100 (∼78%) showed OaPV infections. Further, 42, 35 and 23 blood samples showed single, double and triple OaPV infections, respectively. OaPV1 was responsible for 22 single infections, OaPV2 caused 16 single infections and OaPV3 and OaPV4 caused two single infections each. OaPV1 and OaPV2 were the most frequent ovine viruses in dual and triple infections. In many blood samples, both ovine deltapapillomavirus and dyokappapapillomavirus were found to be transcriptionally active, as shown by the detection and quantification of E5 oncogene transcripts for OaPV1, L1 transcripts for OaPV2, E6 and E7 transcripts for OaPV3 and E6 for OaPV4. OaPVs were found in the blood samples from cattle that shared grasslands rich in bracken ferns known to contain immunosuppressant substances. Furthermore, OaPVs were also found in cattle from intensive livestock farming without any contact with sheep. Because OaPV DNA was detected in both grass hay and corn silage, it is conceivable that these feed may be the viral sources.

Effect of dietary concentrate content on feed intake, feed efficiency, and meat quality of Holstein steers fattened in a hot environment.

The objective of this study was to investigate the effect of feeding high and low concentrate diets on feed intake and feed efficiency, the morphological characteristics of the rumen papillae, and meat quality of Holstein steers fattened under hot climate conditions in Oman. Ten male Holstein calves, of 5 months of age, were selected for the experiment. The animals were fed concentrate and Rhodes grass hay and were divided into two groups of high concentrate (HC, n = 5) and low concentrate diets (LC, n = 5), in which their feed intake, weight gain, and feed efficiency were evaluated across three growing periods. Feed intake and efficiency and average daily gain (ADG) of the HC group were significantly greater than for the LC group and were affected by the diet (p < .01) and the period (p < .001). Across the fattening periods, ADG declined in both groups, with ADG improved by 35% for steers on the HC diet compared to steers on the LC diet. Carcass meat quality was not affected significantly by the dietary concentrate level. In conclusion, our results can be used to make improvements in feed efficiency of Holstein steers under hot climate conditions.

Increasing hay inclusion in silage-based receiving diets and its effects on performance and energy utilization in newly weaned beef steers.

The influence of grass hay (GH) inclusion in replacement of corn silage in receiving diets on growth performance and dietary net energy (NE) utilization was evaluated in newly weaned beef steers (n = 162 Charolais-Red Angus cross steers; initial body weight [BW] = 278 ± 13.4 kg). Treatments were (DM basis): 1) 0% GH, 2) 10% GH, or 3) 20% GH inclusion in replacement of corn silage in receiving diets fed to newly weaned beef steers for 56 d. The study was conducted from October to December of 2019. Data were analyzed as randomized complete block design with pen serving as the experimental unit for all analyses. Increasing dietary inclusion of hay had no influence (P ≥ 0.11) on final BW, ADG, gain:feed or observed/expected dietary NEM and NEG, observed/expected dry matter intake (DMI), or observed/expected ADG. GH inclusion increased (linear effect, P = 0.01) DMI. Observed DMI for all treatments was approximately 15% to 17% less than anticipated based upon steer growth performance and tabular NE values. Evaluation of observed/expected ADG was 31% to 37% greater than expected for the steers in the present study. Particles less than 4 mm increased (linear effect, P = 0.01) and greater than 4 mm decreased (linear effect, P = 0.01) as GH replaced corn silage in the receiving diet. As the proportion of particles greater than 4 mm increased, cumulative ADG was decreased. These data indicate that GH should be considered in corn silage-based receiving diets to improve DMI. In high-risk calves, improved DMI could result in a lesser incidence of morbidity, although no morbidity was observed in any steers from the present study.

Influence of feeding a grass hay diet during the early stage of the fattening period on growth performance, carcass characteristics, and meat production in Japanese Black steers.

The present study investigated the influence of feeding a large amount of grass hay to steers from the early to middle fattening period on growth, carcass characteristics, and meat characteristics. Steers were randomly divided into grass hay-fed (GHF, n = 6) and concentrate-fed (CF, n = 6) groups. The dressed weight of the GHF steers was lower than that of the CF steers, but the final body weight was not significantly different between the groups. The GHF steers had decreased subcutaneous fat and rib thickness compared with the CF steers. Lipid content, monounsaturated fatty acids, and drip loss in the muscles were lower in the GHF steers than in the CF steers. Furthermore, n-3 polyunsaturated fatty acids were higher in the GHF steers compared with the CF steers. The GHF steers had lower body weight during the middle fattening stage, which may have occurred as a result of muscle growth suppression caused by increased Myostatin expression; an increase in daily gain during the finishing period may have occurred as a result of muscle growth activation caused by decreased Myostatin expression. Feeding steers a grass hay-based diet during the early fattening period possibly maintains the quantitative productivity of beef similarly to feeding a concentrate-based diet.

Rumen liquor from slaughtered cattle as inoculum for feed evaluation.

Use of nonlinear mathematical models has been majorly based on in vitro gas production (GP) data generated when substrates are incubated with rumen liquor from fistulated steers. However, existing evidence suggests that rumen liquor from slaughtered cattle of unknown dietary history also generates quantifiable in vitro GP data. Fitting and description of GP data obtained from 4 diets incubated with rumen liquor from slaughtered cattle was evaluated using single-pool exponential model with discrete lag time (EXPL), logistic (LOG), Groot's (GRTS) and Gompertz (GOMP) models. Diets were formulated by varying proportions of Rhodes grass (Chloris gayana) hay and a concentrate mixed on dry matter basis to be: 1,000 g/kg Rhodes grass hay (RGH) and 0 of the concentrate (D1), 900 g/kg RGH and 100 g/kg concentrate (D2), 800 g/kg RGH and 200 g/kg concentrate (D3), 700 g/kg RGH and 300 g/kg concentrate (D4). Dietary kinetics for the models were determined by measuring GP at 2, 4, 8, 10, 18, 24, 36, 48, 72, 96 and 120 h. Model comparison was based on derived GP kinetics, graphical analysis of observed versus predicted GP profiles plus residual distribution and goodness-of-fit from analysis of root mean square error (RMSE), adjusted coefficient of determination (Adj-R2) and Akaike's information criterion (AIC). Asymptotic GP, half-life and fractional rate of GP differed (P < 0.001) among the 4 models. The RMSE, Adj-R2 and AIC ranged from 1.555 to 4.429, 0.906 to 0.984 and 2.452 to 15.874, respectively, for all diets compared across the 4 models. Based on the goodness-of-fit statistical criterion, GP profiles of D1 were more appropriately fitted and described by GRTS and GOMP than the EXPL and LOG models. The GRTS model had the lowest AIC value for D2 (2.452). Although GRTS model had the most homogenous residual dispersion for the 4 diets, all the 4 models exhibited a sigmoidal behavior. Therefore, rumen liquor from slaughtered cattle of unknown dietary history can be used to derive nutritionally important feed parameters, but choice of the most appropriate model should be made based on fitting criteria and dietary substrates incubated.

Sugarcane bagasse or elephant grass hay in diets for goats: Performance, feeding behavior and carcass characteristics

Background: Novel feeding strategies should be developed to produce high-quality meat in current goat production systems. Objective: To evaluate the effects of castration and the association of spineless cactus with sugarcane bagasse or elephant grass hay on nutrient intake, digestibility, performance, feeding behavior and carcass traits of feedlot kids. Methods: A total of 24 male kids (12 castrated and 12 intact), with an average initial weight of 18.5 ± 3.8 kg were allotted to a completely randomized 2 x 2 factorial design (sugar cane bagasse or elephant grass hay; intact or castrated), and confined for 70 days. Results: Nutrient intake and animal performance were similar between treatments. Sugarcane bagasse increased, when compared to elephant grass hay, the digestibility of dry matter (66.12 vs 62.88; p=0.005), crude protein (74.26 vs 70.95; p=0.029) and non-fibrous carbohydrates (91.94 vs 83.07; p<0.001). The forage source affected the time spent resting, ruminating and total chewing time, but there was no effect of diet on feeding and rumination efficiencies. Elephant grass hay increased, when compared to sugarcane bagasse, hot carcass weight (9.87 vs 10.79; p=0.025) and hot carcass yield (43.81 vs 46.87; p=0.013). Intact kids produced heavier hot carcasses when compared with castrated kids (10.80 vs 9.86; p=0.014). Conclusion: Feeding intact or castrated kids with sugar cane bagasse or elephant grass hay do not affect nutrient intake and performance. Feedlot goats have improved carcass traits if kept intact and fed elephant grass hay.

Antecedentes: Se requiere desarrollar nuevas estrategias de alimentación para producir carne de alta calidad en los sistemas actuales de producción de cabras. Objetivo: Evaluar el efecto de la castración y asociación de palma forrajera con bagazo de caña de azúcar o heno de pasto elefante sobre la ingesta de nutrientes, digestibilidad, rendimiento, comportamiento de alimentación y caracteristicas de la canal de cabritos de engorde. Métodos: Un total de 24 cabritos (12 castrados y 12 intactos) con peso inicial promedio de 18,5 ± 3,8 kg fueron asignados a un diseño factorial 2 x 2 completamente al azar (bagazo de caña de azucar o heno de pasto elefante; castrados o intactos) y confinados durante 70 días. Resultados: La ingesta de nutrientes y el rendimiento animal fueron similares entre tratamientos. El bagazo de caña de azúcar aumentó, en comparación con el heno de pasto elefante, la digestibilidad de la materia seca (66,12 vs 62,88; p=0,005), de la proteína cruda (74,26 vs 70,95; p=0,029) y de los carbohidratos no fibrosos (91,94 vs 83,07; p<0,001). La fuente de forraje afectó el tiempo de descanso, de rumia, y el tiempo total de masticación, pero no hubo efecto de la dieta sobre la eficiencia alimentacia y de la rumia. El heno de pasto elefante aumentó, en comparación con el bagazo, el peso de la canal caliente (9,87 vs 10,79; p=0,025) y el rendimiento de la canal caliente (43,81 vs 46,87; p=0,013). Los animales intactos produjeron canales calientes más pesadas en comparación con los castrados (10,80 vs 9,86; p=0,014). Conclusión: La alimentación de cabritos enteros o castrados con bagazo de caña de azúcar o heno de pasto elefante no afecta la ingesta de nutrientes y el rendimiento. Los cabritos tienen mejores características de canal si se alimentan con heno de pasto elefante y se dejan enteros.

Antecedentes: Novas estratégias de alimentação devem ser desenvolvidas para produção de carne de qualidade nos atuais sistemas de produção de caprinos. Objetivo: Avaliar o efeito da castração e da associação da palma forrageira com o bagaço de cana de açúcar ou feno de capim elefante no consumo de nutrientes, digestibilidade, desempenho, comportamento ingestivo e características de carcaça de cabritos confinados. Métodos: Um total de 24 caprinos (12 castrados e 12 não castrados), com peso inicial médio de 18,5 ± 3,8 kg, distribuídos em um delineamento experimental inteiramente casualizado, em arranjo fatorial 2 x 2 (bagaço de cana de açúcar ou feno de capim elefante; inteiros ou castrados), confinados durante 70 dias. Resultados: O consumo de nutrientes e o desempenho dos animais foram semelhante entre os tratamentos. O bagaço de cana elevou, quando comparado com o feno, a digestibilidade da matéria seca (66,12 vs 62,88; p=0,005), proteína (74,26 vs 70,95; p=0,029) e carboidratos não fibrosos (91,94 vs 83,07; p<0,001). As fontes de fibra afetaram os tempos de ócio, ruminação e mastigação total, mas não houve efeito para as eficiências de alimentação e ruminação. O feno de capim elefante aumentou, quando comparado com o bagaço, o peso de caracaça quente (9,87 vs 10,79; p=0,025) e o rendimento de carcaça quente (43,81 vs 46,87; p=0,013). Os animais inteiros produziram carcaças quentes mais pesadas em comparação aos castrados (10,80 vs 9,86; p=0,014). Conclusão: Alimentar caprinos inteiros ou castrados com bagaço de cana ou feno de capim-elefante não interfere no consumo de nutrientes e desempenho. Caprinos confinados terão as características de carcaça melhoradas se mantidos intactos e alimentados com feno de capim elefante.

Effects of grass hay proportion in a corn silage-based diet on rumen digesta kinetics and digestibility in dairy cows.

In this study, we aimed to evaluate the effects of six levels of orchardgrass hay (GH) proportion (0%, 10%, 20%, 30%, 40% or 50% of dry matter) in finely chopped corn silage (CS)-based diets on digesta kinetics of CS and GH in the rumen. Six non-lactating, rumen-cannulated Holstein cows were used in a 6 × 6 Latin square design. Ruminal digesta kinetics was measured by ruminal dosing of feed particle markers (dysprosium for CS, erbium for GH) followed by fecal sampling. The increase of GH proportion had a quadratic effect (P < 0.01) on total tract digestibility of neutral detergent fiber (NDF) and acid detergent fiber. The proportion of GH did not affect the particle size distribution of rumen digesta, total weight of dry matter or NDF in the rumen. The rates of large particle size reduction in the rumen for CS tended to increase linearly with increasing GH proportion (P = 0.077). A quadratic effect (P < 0.05) was found with increasing the GH proportion for the ruminal passage rate of small GH particles, but not for CS particles. The results suggested that associative effects between CS and GH could be generated on rumen digesta kinetics when cows were fed a CS-based diet with an increased proportion of GH.

Effect of Millettia ferruginea (Birbra) foliage supplementation on feed intake, digestibility, body weight change and carcass characterstics of Washera sheep fed natural pasture grass hay basal diet.

Twenty-four yearling male local Washera lambs with an average initial body weight of 18.14 ± 1.07 kg were used to assess the nutritional value of Millettia ferruginea. Experimental animals were grouped into six blocks of four animals, and each animal was randomly assigned to one of the four dietary treatment feeds. The treatments used were; Sole natural pasture grass hay (T1), and 150, 300, 450 g DM Millettia ferruginea leaf hay with ad libitum natural pasture grass hay assigned for (T2), (T3) and (T4), respectively. The feeding trial was carried out for 80 days followed by a 10 days of digestibility trial. Carcasses of each experimental animal were evaluated at the end of the digestibility experiment. Millettia ferruginea leaf hay had 224.6, 556.6, 360.7and 127.4 g/kg crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL), respectively. The average intakes of Millettia ferruginea leaf hay were 0, 133, 263 and 253 g/day for T1, T2, T3 and T4, in that order. The proportions of Millettia ferruginea leaf hay intake from the total dry matter (DM) were 0, 23.5, 44.1, and 43.3% for T1, T2, T3 and T4, respectively. The total DM intake was not significant but showed a trend of T1 > T3 > T4 > T2. CP intake was higher for T3 and T4 with the least intake for T1. Final body weight measurement was higher for T3 and T1 but lower and negative for T2 and T4. Generally, body weight measurements were not consistent in the supplemented groups throughout the trial period. The weight of heart, spleen, and liver were higher for the supplemented groups compared to the sole grass hay. From the results of the current study, it can be concluded that, Millettia ferruginea had some limiting factors, which prevented the animal from efficiently utilize it. Therefore, this study revealed the indispensable role of animal feeding experiments with target animals to examine such impacts.