Average Dry Matter Intake Research Articles

275 Phenotypic relationships between heart score and feed efficiency, carcass, and pulmonary arterial pressure traits

Abstract Pulmonary hypertension (PH) can lead to premature mortality in fed cattle and is often called Feedlot Heart Disease (FHD). To date, pulmonary arterial pressure (PAP) has been the only indicator trait of PH that has been evaluated. The objective of this study was to evaluate relationships between heart score (using heart score as a phenotype for PH) and PAP, carcass, and feed efficiency traits in fattening Angus steers. Our hypothesis was that feed efficiency and carcass traits, along with PAP, would demonstrate a strong relationship with heart score. Feed efficiency, carcass, PAP and heart score data from 89 Black Angus steers from Colorado State University Beef Improvement Center were collected and used for this study. Evaluations were performed using a multiple linear regression model, which included heart score as a categorical fixed effect and age as a continuous fixed effect. Least Square Means, pairwise comparisons, and ANOVA tables were constructed per trait. PAP (P < 0.001) showed an important relationship to heart score and average dry matter (P < 0.10) intake approached importance to heart score. In general, feed efficiency and carcass traits decreased as heart score increased, but PAP was the only trait with a strong relationship to heart score (P < 0.05). This led us to reject our hypothesis.

PSI-14 Feeding β-agonists under heat stress conditions in feedlot cattle

Abstract Red Angus steers (n = 24; 260 ± 25 kg) were used to analyze the effects of supplementation of zilpaterol hydrochloride (ZH) under heat stress conditions on respiration rate (RR), rectal temperature (RT), growth performance (GP), and carcass traits (CT). Steers were randomly assigned to a 2 x 2 factorial treatment arrangement (n = 6/group) with factors including heat stress (HS; THI=71 to 83) or thermal neutral (TN; THI=27 to 39) conditions and with/without supplementation of ZH (0 or 8.38 mg/kg/d on 88% DM basis). Steers were provided 9 d to acclimate to tie stalls rooms under TN conditions before starting the study. TN steers were pair-fed to the average daily dry matter intake (DMI) of HS steers. Ad libitum water consumption (WC) was recorded daily. HS and TN steers were harvested on d 22 and 23, respectively. By design, DMI was not different between environments (P = 0.43). DMI also did not differ between supplement groups (P = 0.31). RT, RR, and WC were greater (P < 0.01) in HS steers compared to TN steers. There was a supplement by environment interaction (P = 0.02) for RT, as HS steers fed ZH had lower RT than HS control steers (39.1 vs 39.5 ℃). ADG was 20% higher (P = 0.04) in HS steers compared to TN steers. CT did not differ (P = >0.05) due to environment, treatment, or interactions between environment and ZH supplementation. Our results suggest that feedlot steers under our experimental conditions display some sensitivity to HS through GP, RR, and RT, however, this did not translate to an impact on CT. Furthermore, ZH supplementation under HS conditions appears to impact thermoregulatory responses positively, yet this did not impact GP or CT.

257 Beef cows with atypical estrous cyclicity at puberty produced calves with deficits in pre-weaning muscling, metabolic indicators, and myoblast function but not in feedlot performance

Abstract Economic beef production requires efficient growth. In our herd, cows were identified that exhibited irregular (start-stop) or absent (non-cyclic) pubertal estrous cyclicity prior to their 1st breeding season. These cows were sub-fertile but weaned heavier calves. Here, we determined if these calves possessed enhanced muscling and metabolic efficiency. Early muscle growth and metabolic indicators, feedlot performance, and carcass traits were evaluated in steer calves from cows that had exhibited normal (typical), start-stop, or non-cyclic pubertal estrous patterns. Start-stop and non-cyclic cows calved later (P < 0.05) than typical cows, but calf birthweights did not differ among groups. Weaning weights tended to be decreased (P = 0.09) in calves from start-stop and non-cyclic cows, but 205-d adjusted weaning weights did not differ. At 3 mo, body composition estimated by bioelectrical impedance revealed a tendency for reduced (P = 0.10) muscle mass in calves from non-cyclic and start-stop compared to typical cows. Plasma cholesterol, high-density lipoprotein, and triglyceride concentrations were reduced (P < 0.05) and glucose/insulin tended to be increased (P = 0.09) in calves from non-cyclic cows. Plasma urea nitrogen did not differ among groups. Ex vivo proliferation was greater (P < 0.05) for myoblasts isolated from calves of start-stop and non-cyclic compared to typical cows. Total oxidative metabolism did not differ but glycolysis was decreased (P < 0.05) in myoblasts from calves of non-cyclic cows. Feedlot average daily gain and dry matter intake did not differ during growing or finishing. Feed efficiency tended to be increased (P = 0.09) in calves from non-cyclic cows but not when normalized to dressing percentage. Hot carcass weight, dressing percentage, ribeye area, fat thickness, and marbling did not differ among groups. These findings indicate that atypical maternal estrous cyclicity at puberty reduced early muscle growth and metabolism in offspring but not feedlot growth or carcass merit. We speculate that early growth deficits are influenced by inflammatory changes.

43 Effects of steroidal implants on feedlot growth performance, carcass characteristics, and serum and meat estradiol-17β concentrations of Holstein steers

Abstract Objectives were to determine the effects of implants on growth performance, carcass characteristics, and estradiol-17β (E2) concentrations in the serum and longissimus muscle of Holstein steers fed a grain-based diet. Seventy Holstein steers (initial BW = 275 ± 6.4 kg) were assigned to treatments: (1) Implanted on d 0 with Component TE-IS with Tylan (Elanco Animal Health, Greenfield, IN) and on d 84 with Component TE-S with Tylan (Elanco Animal Health) of the experiment; or (2) not implanted (control). Implanted Holstein steers were heavier (P ≤ 0.01) than nonimplanted Holstein steers on d 84, at time of reimplant, and at the end of the experiment (d 186). Implanting Holstein steers increased (P < 0.01) average daily gain (ADG) and dry matter intake (DMI) without affecting (P = 31) gain-to-feed ratio (G:F) when compared to steers that were not implanted. Carcasses from implanted Holstein steers had greater (P < 0.01) hot carcass weights (HCW) and longissimus muscle (LM) area than carcasses from nonimplanted steers. Implanting did not affect (P ≥ 0.21) other carcass characteristics. There was an increase (P = 0.03) of 1.3 pg of E2/g of muscle when LM from implanted Holstein steers was compared to LM from nonimplanted steers. There was an implant × day interaction (P < 0.01) in circulating serum E2 concentrations. Serum E2 concentrations remained relatively constant in nonimplanted Holstein steers. In implanted steers, serum E2 concentrations increased (P < 0.01) after each implant. Serum E2 peaked at 28 d after the first implant and then declined after d 56. Implanting Holstein steers fed grain-based diets increased ADG, HCW, and LM area due to increased circulating E2 concentrations. Implants did increase LM E2 concentrations; however, changes were minimal compared to E2 concentrations in other human foods and were not great enough to warrant concerns regarding meat consumption from implanted animals.

185 Utilizing craft brewing side streams of trub, hops, and yeast mix (THYM) as a novel feed additive and an alternative to monensin in beef cattle diets

Abstract The objective of this experiment was to evaluate craft brewing side streams of trub, hops and yeast mix (THYM) as a potential feedstuff and replacement for monensin in growing beef cattle rations. British-cross steers (n = 45, initial BW = 732 ± 58kg) were stratified by BW and randomly assigned to 1 of 15 pens (3 head/pen). Treatment diets were randomly assigned to pen and consisted of a corn silage based total mixed ration (TMR) with no supplementation (CON; 70.99% TDN, 12.25% CP), supplementation with monensin (MON; 22g/907kg ration, dry matter basis) or supplementation with the brewery side streams (THYM; 70.95% TDN, 12.49% CP, 2.65% THYM, dry matter basis). Steers were adjusted to a TMR for 14 d prior to a 63 d collection period. Body weight and serum urea nitrogen (SUN) were measured on d 0 and every 21 d thereafter. Rumen fluid was collected via esophageal/rumen tube at d 42 and 63 for short chain fatty acid analysis (SCFA). Data were analyzed using the MIXED procedure of SAS 9.4 (Cary, NC) with treatment as the main effect and using repeated measures. Average daily gain and dry matter intake did not differ among treatments (P = 0.96, respectively), but a tendency was noted for THYM to have greater average gain:feed than the CON treatment. SUN concentrations were least on d 0 (P < 0.01) but did not differ among treatments at any time (P =0.11). On d 42, THYM had a greater (P = 0.05) A:P than MON. Concentrations of propionic and valeric acid were greater (P < 0.05) for CON than THYM on d 63, while SCFA concentrations tended to be greater (P = 0.08) for CON than THYM. THYM also tended to have a greater A:P on d 63 than CON. Interpretation of the data indicates that inclusion of THYM in growing cattle rations has no negative impact on animal performance.

RETRACTED: 186 Utilizing craft brewing side streams of trub, hops, and yeast mix (THYM) as a novel feed additive and an alternative to monensin in beef cattle diets

Abstract The objective of this experiment was to evaluate craft brewing side streams of trub, hops and yeast mix (THYM) as a potential feedstuff and replacement for monensin in growing beef cattle rations. British-cross steers (n = 45, initial BW = 732 ± 58kg) were stratified by BW and randomly assigned to 1 of 15 pens (3 head/pen). Treatment diets were randomly assigned to pen and consisted of a corn silage based total mixed ration (TMR) with no supplementation (CON; 70.99% TDN, 12.25% CP), supplementation with monensin (MON; 22g/907kg ration, dry matter basis) or supplementation with the brewery side streams (THYM; 70.95% TDN, 12.49% CP, 2.65% THYM, dry matter basis). Steers were adjusted to a TMR for 14 d prior to a 63 d collection period. Body weight and serum urea nitrogen (SUN) were measured on d 0 and every 21 d thereafter. Rumen fluid was collected via esophageal/rumen tube at d 42 and 63 for short chain fatty acid analysis (SCFA). Data were analyzed using the MIXED procedure of SAS 9.4 (Cary, NC) with treatment as the main effect and using repeated measures. Average daily gain and dry matter intake did not differ among treatments (P = 0.40 and P = 0.96, respectively), but a tendency was noted for THYM to have greater average gain:feed than the CON treatment. SUN concentrations were least on d 0 (P < 0.01) but did not differ among treatments at any time (P =0.11). On d 42, THYM had a greater (P = 0.05) A:P than MON. Concentrations of propionic and valeric acid were greater (P < 0.05) for CON than THYM on d 63, while SCFA concentrations tended to be greater (P = 0.08) for CON than THYM. THYM also tended to have a greater A:P on d 63 than CON. Interpretation of the data indicates that inclusion of THYM in growing cattle rations has no negative impact on animal performance.

Extruded feed in different volume-concentrate ratios: in-vitro fermentation kinetics, consumption, and evaluation of lambs’ metabolic profile

This study aimed both to evaluate the metabolic profile of lambsfed with extruded forage and concentrate containing different roughageconcentrate ratios (R:C) and to evaluate in-vitro ruminal fermentationkinetics of these rations. An experiment was carried out with 20 weanling,female crossbred lambs (½Dorper x ½Santa Inês) aged 120 ± 8 days. Thetreatments were four R:C ratios of extruded forage (Foragge®) and extrudedconcentrate (Beef Total®) – 30%F:70%C, 40%F:60%C, 50%F:50%C, and60%F:40%C – distributed randomly with five replicates. The analysistargeted energy metabolites (VLDL, triglycerides, and cholesterol), hepaticmetabolites (alkaline phosphatase, gamma glutamyltransferase [GGT], andaspartate aminotransferase [AST]), and protein metabolites (total protein,uric acid, urea, creatinine, albumin, and globulin). In-vitro gas productionwas quantified by inoculating the extruded rations in bovine ruminal fluidwith the following forage:concentrate proportions evaluated: 30%F:70%C,40%F:60%C, 50%F:50%C, 60%F:40%C and 70%F:30%C. Fermentationkinetic values were compared using parallelism test and curve identity atthe error probability level of 5%. A regression study was used to compare themeans of the metabolites at the error probability level of 5%. Average drymatter intake data are provided descriptively. The extruded rationincreased the hepatic metabolites (GGT and AST) without compromising theliver and kept the energy metabolites stable. Similarly, the serumconcentration of protein metabolites remained at normal levelsrecommended to the ovine species. In-vitro fermentation pattern displayedhigh gas production associated with high ration digestibility. The extrudedration provides protein and energy supply to meet the animals’ nutritionalrequirements without compromising their health.

Liability to diseases and their relation to dry matter intake and energy balance in German Holstein and Fleckvieh dairy cows

Dairy cow efficiency is increasingly important for future breeding decisions. The efficiency is determined mostly by dry matter intake (DMI). Reducing DMI seems to increase efficiency if milk yield remains the same, but resulting negative energy balance (EB) may cause health problems, especially in early lactation. Objectives of this study were to examine relationships between DMI and liability to diseases. Therefore, cow effects for DMI and EB were correlated with cow effects for 4 disease categories throughout lactation. Disease categories were mastitis, claw and leg diseases, metabolic diseases, and all diseases. In addition, this study presents relative percentages of diseased cows per days in milk (DIM), repeatability, and cow effect correlations for disease categories across DIM. A total of 1,370 German Holstein (GH) and 287 Fleckvieh (FV) primiparous and multiparous dairy cows from 12 dairy research farms in Germany were observed over a period of 2 yr. Farm staff and veterinarians recorded health data. We modeled health and production data with threshold random regression models and linear random regression models. From DIM 2 to 305 average daily DMI was 22.1 kg/d in GH and 20.2 kg/d in FV. Average weekly EB was 2.8 MJ of NEL/d in GH and 0.6 MJ of NEL/d in FV. Most diseases occurred in the first 20 DIM. Multiparous cows were more susceptible to diseases than primiparous cows. Relative percentages of diseased cows were highest for claw and leg diseases, followed by metabolic diseases and mastitis. Repeatability of disease categories and production traits was moderate to high. Cow effect correlations for disease categories were higher for adjacent lactation stages than for more distant lactation stages. Pearson correlation coefficients between cow effects for DMI, as well as EB, and disease categories were estimated from DIM 2 to 305. Almost all correlations were negative in GH, especially in early lactation. In FV, the course of correlations was similar to GH, but correlations were mostly more negative in early lactation. For the first 20 DIM, correlations ranged from -0.31 to 0.00 in GH and from -0.42 to -0.01 in FV. The results illustrate that future breeding for dairy cow efficiency should focus on DMI and EB in early lactation to avoid health problems.

Effect of Flaxseed Oil on Feeding Dairy Friesian Cows on the Fatty Acid and Chemical Composition of Milk and Physiochemical Properties of Yoghurt

The aim of this study to evaluate the effect of flaxseed oil supplementation into Friesian cows on their productive, blood parameters, fatty acids composition of milk, and physic-chemical properties of yoghurt. Twenty-four Friesian cows averaged 607±22.5 kg live body weight were randomly assigned into two groups (12 cows in each group). Cows in group 1st (T1) was served as the control, while those in (T2) 2nd were treated with 2% of DM intake flaxseed oil from until 120 days post-partum. An average daily dry matter intake DM and TDN increased significantly (P≤0.05) with flaxseed oil, compared to the control. The intake DCP, protein, and solids-not-fat contents were nearly similar in both treatments. Concentrations of high-density lipoprotein, triglyceride, contents of fat, lactose and total solids were higher significantly (P<0.05) in T2 than the (T1). Daily milk yield and 4% fat corrected milk were higher significantly by 18.08 in T2 and 13.91% in T1, respectively. Treatment (T2) was slightly lower amounts of small-chain and medium-chain fatty acids (C4- C10), whereas (C12-C16) were slightly higher in control. DM, fat, ash and titratable acidity of yoghurt were significantly higher (P≤0.05) in treatment T2, whereas pH was similar in both treatments. Treatment (T1) was contained a fewer total bacterial count than the treatment (T2). Yeasts and Coliforms were not discovered in all treatments. The treatment (T2) contained the decreased value of the omega-6/omega-3 ratio. It could be concluded that flaxseed oil improved digestibility, increased the concentrations of polyunsaturated fatty acid, reduced the concentrations of saturated fatty acids, increased the (omega 3) in milk and yoghurt.

The effect of probiotics, phytobiotics and their combination as feed additives in the diet of dairy calves on performance, rumen fermentation and blood metabolites during the preweaning period

This study aimed to evaluate whether probiotics, phytobiotics or their combination as feed additives, given during the preweaning period to neonatal calves, can enhance calf health, performance, and metabolic status. 44 Polish neonatal Holstein-Friesian calves were grouped by sex (22 female and 22 male) and parity (22 born to primiparous cows and 22 born to multiparous cows) and assigned randomly to 4 treatment groups (11 calves each): control (CON, without feed additive), multi-strain Lactobacillus probiotic (PRO, 250 mg/calf/d), phytobiotic (PH, 50 mg rosmarinic acid/calf/d), and the combination of probiotics and phytobiotics (PROPH, combined PRO and PH treatments). The feed additives were provided into colostrum as well as milk replacer immediately before feeding. During the first 12 h of life, calves received 4 L colostrum; on days 2 and 3: 2 meals/d of 2 L of transition milk; from days 5 to 49: 6 L/d of milk replacer (150 g powder as feed/L) in 3 feedings; and from days 50 to 56 : 2 L/d of milk replacer in 1 feed. The PROPH calves had higher body weights on days 28 (P = 0.021) and 56 (P = 0.015) compared to the CON group. Incorporation of the combination of probiotics and phytobiotics as feed additive had significant beneficial effects on average daily gain, starter intake and total dry matter intake (P ≤ 0.05) over the experimental period. Throughout the study, the diarrheal scores 3 (mild diarrhea) and 4 (severe diarrhea) were 2.8 (P = 0.022) and 2.7 (P = 0.016) times lower, respectively, for PROPH calves compared to the scores of the CON calves. In addition, the PROPH calves had lower numbers of parasite oocysts/cysts per gram of feces on d 28 (P = 0.021) and the percentage of Cryptosporidium infected calves was lower on d 28 (P = 0.025) and 56 (P = 0.019). The PROPH calves had higher total counts for ruminal volatile fatty acids (P ≤ 0.05), bacteria and protozoa (P < 0.001). The PROPH treatment resulted in the highest concentrations of blood insulin-like growth factor-I and β-hydroxybutyrate (P ≤ 0.05) for the 29 to 56 day period and the entire experimental period. In conclusion, adding the combination of probiotics and phytobiotics as feed additive to diet of dairy calves during the preweaning period can improve health, performance, rumen fermentation and biochemical blood indices. However, the dietary inclusion of phytobiotic with rosmarinic acid as the main bioactive component or probiotic as a single feed additive does not affect growth performance and physiology indices.

Influence of crushed maize and soybean cake on the growth of crossbred female calves

The present research work was conducted to develop a balanced ration for crossbred high yielding calves in farm condition. For this purpose, seventy days long feeding trial was conducted with nine crossbred female calves having nearly similar body weight and age. Nine crossbred calves were equally divided into three groups such as T1 (1 kg concentrate mixture of crushed maize, wheat bran, mustard oil cake, molasses, DCP and salt at a ratio of 25:45:22:5:1:2, respectively), T2 (1 kg concentrate mixture of crushed maize, wheat bran, soybean cake, molasses, DCP and salt at a ratio of 27:45:20:5:1:2, respectively) and T3 (Wheat bran, rice polish, mustard oil cake, DCP, Salt were supplied according to BAU routine farm feeding at a ratio of 65:18:14:1:2, respectively). All calves were supplied with ad libitum green grasses (German and Para) and fresh clean drinking water. From the research finding, it was observed that the average total dry matter intake, total body weight gain, body length gain and heart girth gain were in T1 (2.68a±0.000 kg, 2.51a±0.21 kg, 1.83a±0.12 cm, 1.29a±0.07 cm, respectively) and T2 (2.65a±0.001 kg, 2.55a±0.21 kg, 1.67a±0.12 cm, 1.25a±0.07 cm, respectively) groups significantly (p&lt;0.05) higher than that of the T3 (2.34b±0.002 kg, 0.96b±0.21 kg, 0.81b±0.12 cm, 0.64b±0.07 cm, respectively) group. The result showed that the body weight gain of T2 group was higher by supplementation of balanced ration. Therefore, the feed supplementation of crushed maize, wheat bran, soybean cake, molasses, DCP and salt at a ratio of 27:45:20:5:1:2, respectively should be supplied to crossbred calves for the future development of dairy herd replacement stock for profitable dairy business.&#x0D; Asian J. Med. Biol. Res. September 2020, 6(3): 499-506

Antimethanogenic effects of nitrate supplementation in cattle: A meta-analysis

Supplementing a diet with nitrate is regarded as an effective and promising methane (CH4) mitigation strategy by competing with methanogens for available hydrogen through its reduction of ammonia in the rumen. Studies have shown major reductions in CH4 emissions with nitrate supplementation, but with large variation in response. The objective of this study was to quantitatively investigate the effect of dietary nitrate on enteric CH4 production and yield and evaluate the variables with high potential to explain the heterogeneity of between-study variability using meta-analytical models. A data set containing 56 treatments from 24 studies was developed to conduct a meta-analysis. Dry matter (DM) intake, nitrate dose (g/kg of DM), animal body weight, roughage proportion of diet, dietary crude protein and neutral detergent fiber content, CH4 measurement technique, and type of cattle (beef or dairy) were considered as explanatory variables. Average DM intake and CH4 production for dairy cows (16.2 ± 2.93 kg/d; 311 ± 58.8 g/d) were much higher than for beef cattle (8.1 ± 1.57 kg/d; 146 ± 50.9 g/d). Therefore, a relative mean difference was calculated and used to conduct random-effect and mixed-effect model analysis to eliminate the large variations between types of animal due to intake. The final mixed-effect model for CH4 production (g of CH4/d) had 3 explanatory variables and included nitrate dose, type of cattle, and DM intake. The final mixed-effect model for CH4 yield (g of CH4/kg of DM intake) had 2 explanatory variables and included nitrate dose and type of cattle. Nitrate effect sizes on CH4 production (dairy: -20.4 ± 1.89%; beef: -10.1 ± 1.52%) and yield (dairy: -15.5 ± 1.15%; beef: -8.95 ± 1.764%) were significantly different between the 2 types of cattle. When data from slow-release nitrate sources were removed from the analysis, there was no significant difference in type of cattle anymore for CH4 production and yield. Nitrate dose enhanced the mitigating effect of nitrate on CH4 production and yield by 0.911 ± 0.1407% and 0.728 ± 0.2034%, respectively, for every 1 g/kg of DM increase from its mean dietary inclusion (16.7 g/kg of DM). An increase of 1 kg of DM/d in DM intake from its mean dietary intake (11.1 kg of DM/d) decreased the effect of nitrate on CH4 production by 0.691 ± 0.2944%. Overall, this meta-analysis demonstrated that nitrate supplementation reduces CH4 production and yield in a dose-dependent manner, and that elevated DM intake decreases the effect of nitrate supplementation on CH4 production. Furthermore, the stronger antimethanogenic effect on CH4 production and yield in dairy cows than in beef steers could be related to use of slow-release nitrate in beef cattle.

Associations of mucosal disaccharidase kinetics and expression in the jejunum of steers with divergent average daily gain.

The objective of this study was to quantify the differences in the activity of jejunal maltase and isomaltase between two groups of steers with average dry matter intake (DMI) and differing average daily gain (ADG). DMI and ADG were measured in crossbred steers (n = 69; initial body weight = 456 ± 5.0 kg) consuming a finishing diet containing 67.8% dry-rolled corn, 20.0% wet distillers grains with solubles, 8.0% alfalfa hay, and 4.2% vitamin/mineral supplement on a dry matter basis for 84 d. Jejunal mucosal samples were collected from eight steers with the greatest (high) or least (low) ADG and average DMI (± 0.55 standard deviation). Homogenates of jejunal mucosa were incubated with increasing amounts of maltose and isomaltose to determine the disaccharidase kinetics. Total mucosal protein concentration (mg protein/g tissue; P = 0.45) of the mucosa and small intestinal weights (P = 0.69) did not differ between the groups. Neither the Michaelis-Menten constant (Km) of isomaltase (P = 0.15) nor maltase (P = 0.21) differed between groups. The isomaltase maximum velocity (Vmax) expressed per gram of protein tended to differ (P = 0.10) between groups of steers but did not differ (P = 0.13) when expressed on a tissue basis. Similarly, neither the maltase Vmax expressed per gram of protein (P = 0.31) nor tissue (P = 0.32) differed between groups. While previous studies have indicated that disaccharidase expression is associated with differences in ADG, data presented here indicate that differences in enzyme activity at the end of the finishing period are minimal.

Distinct responses in feed sorting, chewing behavior, and ruminal acidosis risk between primiparous and multiparous Simmental cows fed diets differing in forage and starch levels

During early lactation, both primiparous (PP) and multiparous (MP) cows are commonly fed diets rich in starch and low in forages to support their high energy requirements. Yet, the PP cows experience this dietary challenge for the first time, which might result in higher odds for them to develop rumen and systemic health disorders. The primary objective of this study was to evaluate the effect of decreasing the amount of forages in the diet on chewing and sorting behaviors and rumen and systemic health variables in PP and MP dairy cows. Twenty-four lactating Simmental cows [8 PP, average dry matter intake (DMI) of 19.1 ± 1.1 kg/d; 16 MP, average DMI of 22.5 ± 1.1 kg/d] with a body weight of 737 ± 90 kg and 50 ± 22 days in milk were used in this study. Cows were first fed a total mixed ration with 60% forage and 40% concentrate [on a dry matter (DM) basis] considered marginal in forages for 2 wk. Then, cows were switched to a diet low in forages with 40% forage and 60% concentrate (on a DM basis) for 4 wk. Reticular pH was measured continuously with wireless pH-sensors inserted into the reticulum to calculate the subacute ruminal acidosis (SARA) index. Chewing activity was measured with noseband-sensor halters, and feed sorting was measured weekly. Blood samples were collected weekly and analyzed for metabolic and inflammation markers. Switching PP and MP cows from a marginal to low-forage diet decreased the time spent eating and ruminating per kilogram of DM. Primiparous cows chewed longer per kilogram of DMI than MP cows. Also, the PP cows sorted more pronounced for longer particles and against fine particles than MP cows did. Despite higher rumination activity per kilogram of DMI and the adaptive sorting behavior, the PP cows spent on average 4.6 h/d longer below a pH of 5.8 and had a higher SARA index (i.e., area pH <5.8/DMI) than MP cows, especially during the first week of the low-forage diet (9.5 vs. 4.8). The concentration of liver enzymes increased with the low-forage diet, which was especially pronounced in the PP cows. In conclusion, this study demonstrated greater susceptibility of PP cows to SARA and liver damage than MP cows fed the same diets. Although PP cows demonstrated greater chewing and ruminating activity per kilogram of DMI, as well as adapted sorting behavior in favor of large particles during the low-forage high-starch feeding, they developed more severe signs of SARA. This suggests higher forage fiber requirements for PP cows and the need for improved feeding strategies to mitigate rumen fermentation disorders during early lactation in these cows.

Effects of increasing doses of trenbolone acetate and estradiol on finishing phase growth performance, carcass trait responses, and serum metabolites in beef steers following implantation.

Yearling Simmental × Angus crossbred beef steers (n = 240; allotment BW = 365 ± 22.5 kg) from a South Dakota auction facility were transported 117 km to Brookings, SD and used in a randomized complete block design feedlot study to evaluate the effects of implants (both from Zoetis, Parsippany, NJ) containing increasing doses of trenbolone acetate (TBA) and estradiol benzoate (EB) administered 124 d prior to harvest have on finishing phase growth performance, carcass characteristics, and serum concentrations of urea-N (SUN) and insulin-like growth factor I (IGF-I). Thirty pens (10 pens/treatment) were assigned to 1 of 3 treatments: 1) negative control given no implant (NI); 2) a steroidal implant containing 100 mg TBA and 14 mg EB administered subcutaneously in the center one-third of the ear on day 1 (Synovex Choice, Zoetis, Parsippany, NJ; CH); 3) a steroidal implant containing 200 mg TBA and 28 mg EB administered subcutaneously in the center one-third of the ear on day 1 (Synovex Plus, Zoetis; PL). Cattle were fed for 124 d post-implantation. Steers were fed a common diet throughout the study. Treatment effects were evaluated by the use of orthogonal polynomials. Pen was the experimental unit for all analyses; an α of 0.05 determined significance. There was a quadratic effect (P = 0.01) on carcass-adjusted final BW. Increasing doses of TBA and EB resulted in a linear increase for both average daily gain (P = 0.01) and dry matter intake (P = 0.02). A quadratic effect on gain-to-feed ratio was observed (P = 0.01). No quadratic (P ≥ 0.40) or linear (P ≥ 0.14) effects were observed for dressing percentage, rib fat (RF), calculated yield grade, or marbling scores. A quadratic increase (P = 0.01) in hot carcass weight (HCW) and a linear increase (P = 0.01) in ribeye area (REA) were detected. No significant implant × day interaction (P ≥ 0.09) was noted for serum concentrations of urea-N or IGF-I. Implants decreased (P = 0.01) SUN compared with NI. Serum concentration of IGF-I was increased (P = 0.04) in implanted steers compared with NI steers. In yearling crossbred beef steers, the use of steroidal implants containing a combination of 100 mg TBA + 14 mg EB or 200 mg TBA + 28 mg EB increases growth performance, HCW, and REA at equal RF accumulation without detriment to marbling score compared with nonimplanted steers.

Effects of soft pellet creep feed on pre-weaning and post-weaning performance and intestinal development in piglets.

ObjectiveThis study aimed to determine the effects of soft pellet creep feed (SPCF) on growth performance and intestinal development in piglets.MethodsA total of 18 sows and their litters of crossbred piglets (14±2 days, 3.73±0.72 kg) were assigned to one of three dietary groups receiving i) powder creep feed (PCF), ii) hard pellet creep feed (HPCF) or iii) SPCF during the pre-weaning period. After weaning, piglets were selected for continuous evaluation of the three diets on growth performance and intestinal health.ResultsIn the pre-weaning period, the average daily feed intake and average daily dry matter intake were significantly higher in the SPCF group than the HPCF group (p<0.05). In the post-weaning and entire experimental period, the different diets had no significant effect on growth performance. At 10 d after weaning, the serum glucose concentration was lower in the SPCF group (p<0.05) than the other groups; a higher (p<0.05) villus height and lower (p<0.05) crypt depth in the jejunum were also observed in the SPCF group than the other groups; Meanwhile, in the duodenum and jejunum, the SPCF group had a higher (p<0.05) villus height to crypt depth ratio than the other groups; Furthermore, the higher (p<0.05) threshold cycle values of lactic acid bacteria and lower (p<0.05) threshold cycle values of Clostridium, Enterobacter and Escherichia coli were also observed in the SPCF group, and the sucrase and maltase activity was higher (p<0.05) in the SPCF group than the other groups in duodenum and ileum.ConclusionThe SPCF improved pre-weaning feed intake and decreased the negative effects of weaning stress in the intestine in piglets.

Average daily gain divergence in beef steers is associated with altered plasma metabolome and whole blood immune-related gene expression.

We evaluated the plasma amine/phenol- and carbonyl-metabolome and whole-blood immune gene expression profiles in beef steers with divergent average daily gain (ADG). Forty-eight Angus crossbred beef steers (21 days postweaning; 210 ± 8.5 kg of body weight) were fed the same total mixed ration ad libitum for 42 days with free access to water. After 42 days of feeding, the steers were divided into two groups of lowest (LF: n = 8) and highest ADG (HF: n = 8). Blood samples were taken from all steers. The blood samples from LF and HF steers were used for further analysis. A subsample of the whole blood was immediately transferred into RNA-protect tubes for RNA extraction and messenger RNA expressions of 84 genes involved in innate and adaptive immune responses. Another subsample of the whole blood was immediately centrifuged to harvest the plasma for subsequent metabolome analysis. The average daily dry matter intake of the steers in LF and HF was 6.08 kg ± 0.57 and 6.04 kg ± 0.42, respectively, and was similar between the two groups (P = 0.72). The ADG (1.09 kg ± 0.13) of LF was lower (P = 0.01) than that of HF (1.63 kg ± 0.20). The expressions of 10 immune-related genes were upregulated (FC ≥ 1.2; P ≤ 0.05) in HF steers; these genes were involved in viral pathogen recognition and eradication, defense against intracellular and extracellular pathogens and parasites, and immune response homeostasis. A total number of 42 carbonyl-containing metabolites and 229 amine/phenol-containing metabolites were identified in the plasma samples of both groups. No alteration in carbonyl-metabolome was detected. Ten metabolites with immunomodulatory, anti-inflammatory, and reactive oxygen-scavenging properties were greater (FDR ≤ 0.05) in HF steers, whereas eight metabolites including arginine, phenylalanine, guanidoacetic acid, and aspartyl-threonine were greater in LF steers. This study demonstrated that beef steers with divergent ADG had altered plasma amine/phenol metabolome and immune-related gene expressions in the blood. Notably, plasma metabolites and immune-related genes of great health benefits were greater in steers with high ADG.

Effects of slow-release urea on in vitro rumen fermentation parameters, growth performance, nutrient digestibility and serum metabolites of beef cattle

Two experiments were conducted to investigate the effects of slow-release urea (SRU) on in vitro rumen fermentation parameters, growth performances, nutrient digestibility, and serum metabolites of beef cattle. The single factor design was applied in both experiments. Three diets with different nitrogen sources including soybean meal (Control group), slow-release urea (SRU group), and common urea (Urea group) was designed (concentrate to forage ratio was 4:6). The diets were formulated to be isoenergetic and isonitrogenous, 75% of the soybean meal in the control diet was replaced by 1.41% SRU and 1.15% urea in SRU group and Urea group, respectively. In experiment 1, five healthy Jinjiang cattle (average body weight (BW) was 380 ± 17.1 kg) with permanent rumen fistulas were used in in vitro ruminal fermentation experiment. The results showed that supplementing SRU increased the dry matter degradation rate (DMD), digestible organic matter (DOM) and propionic acid concentration in cultivated fluid, and SRU supplementation decreased pH, NH3-N, total volatile fatty acid (TVFA), acetic acid, butyric acid concentration and microbial growth efficiency (MOEFF) in cultivated fluid. In experiment 2, eighteen Simmental crossbred cattle BW= 315 ± 5.2 kg) were stratified by BW and then assigned to the three groups to have equal BW among groups. The results showed that supplementing SRU reduced the average dry matter intake (ADMI), apparent digestibility of ether extract (EE), the activity of glutathione peroxidase (GSH-Px), the levels of IgG and IgA, and the production of thiiodothronine (T3) in serum, SRU supplementation increased the apparent digestibility of dry matter and organic matter (OM) and alanine aminotransferase (ALT) concentration in serum. These results indicated that some soybean meal could be replaced by SRU and urea in the production of beef cattle. In addition, compared with urea, SRU had a good sustained-release effect. The replacement of some soybean meal by SRU in the diet had no adverse impact on rumen fermentation, growth performance, and serum metabolites of beef cattle.

Looking for high-production and sustainable diets for lactating cows: A survey in Italy

The aim of the present study was to evaluate, through a survey conducted on commercial farms, the global warming potential (GWP) of different lactating cow total mixed rations (TMR) and to identify the best dietary strategies to increase feed efficiency (FE) and reduce enteric CH4 emission. A total of 171 dairy herds were selected: data about dry matter intake (DMI), lactating cow TMR composition, and milk production and composition were provided by farmers. Diet GWP (kg of CO2 equivalents; CO2eq) was calculated as sum of GWP (kg of CO2eq) of each included ingredient, considering inputs needed at field level, feed processing, and transport. For soybean solvent meal, land use change was included in the assessment. Enteric methane production (g/d) was estimated [using the equation CH4 (g/d) = 2.54 + 19.14 × DMI] to calculate CH4 emission for kilograms of fat- and protein-corrected milk (FPCM). The data set was analyzed by generalized linear model and logistic analysis using SAS 9.4 (SAS Institute Inc., Cary, NC). The frequency distribution showed wide variation among farms for GWP (kg of CO2eq) of TMR: approximately 25% of the surveyed farms showed a diet GWP of 15 kg of CO2eq, 20% showed a GWP of 13 kg of CO2eq, and 16.7% showed a GWP of 17 kg of CO2eq. The variation among farms was due to the feedstuffs used. Among feedstuffs, soybean meal (SBM) had the highest correlation with the GWP of the TMR as shown by the following equation: TMR GWP (kg of CO2eq) = 2.49 × kg of SBM + 6.9 (R2 = 0.547). Moreover, diets with inclusion of SBM >15% of dry matter (DM) did not result in higher milk production than diets with a lower inclusion of SBM (≤15%). Average daily milk production of cows was 29.8 [standard deviation (SD) 4.83] kg with fat and protein contents of 3.86% (SD 0.22) and 3.40% (SD 0.14), respectively. The average DMI (kg/d) of lactating cows was 22.3 (SD 2.23). Logistic analysis demonstrated that corn silage ≤30% of diet DM was associated with higher FE. Almost 50% of farms had an average value of 15.0 g of CH4/kg of FPCM and about 30% of farms had an average of 12.5 g of CH4/kg of FPCM. The results demonstrated that lower enteric CH4 production was related to inclusion (% of diet DM) of ≤12% alfalfa hay and >30% corn silage. Diets with >34% neutral detergent fiber had higher CH4 production (>14.0 g/kg of FPCM) than those with lower neutral detergent fiber content. In contrast, lower enteric CH4 production (≤14.0 g/kg of FPCM) was related to diets characterized by net energy of lactation (NEL) >1.61 Mcal/kg and >4% ether extract. The variability in TMR GWP shows significant potential for reducing the GWP of a diet through choice and inclusion levels of ingredients (mainly SBM) and the possibility of decreasing methane enteric emission associated with milk production on a commercial scale.

Effects of butyrate supplementation on blood glucagon-like peptide-2 concentration and gastrointestinal functions of lactating dairy cows fed diets differing in starch content

The objective of this study was to evaluate effects of butyrate supplementation on plasma concentration of glucagon-like peptide-2 (GLP-2), apparent total-tract digestibility, and responses to a grain challenge of lactating dairy cows fed diets differing in starch content. Eight Holstein cows averaging 58.6 ± 9.96 d in milk (4 primiparous cows fitted with rumen cannula and 4 multiparous intact cows) were blocked by parity and assigned to one of two 4 × 4 Latin squares balanced for carryover effects with a 2 × 2 factorial arrangement of treatments. Treatments were dietary starch content [20.6 vs. 27.5%, respectively, for low starch (LS) and high starch (HS)] and butyrate supplementation (butyrate vs. control) with 21-d periods. Butyrate was provided as Gustor BP70 WS (Norel, S.A., Madrid, Spain), containing 70% sodium butyrate and 30% fatty acid mixture, at 2% of dietary dry matter (providing butyrate at 1.1% of dietary dry matter), and control premix contained 70% wheat bran and 30% fatty acid mixture. Feeds, orts, and fecal samples were collected from d 17 to 19 to determine apparent total-tract nutrient digestibility. Blood and rumen fluid samples were collected on d 19. The baseline of dry matter intake (DMI) was determined as average DMI from d 17 to 19 for each cow, and cows were feed-restricted at 60% of the baseline DMI on d 20, and a grain challenge was conducted by providing steam-flaked corn grain at 0.6% of body weight, on an as-fed basis, in addition to each treatment diet on d 21, and blood and ruminal fluid samples were collected. The interaction of dietary starch content by butyrate supplementation was significant for plasma GLP-2 concentration, being greater for cows fed butyrate with the HS diet than those fed the other 3 diets. Cows fed butyrate increased n-butyrate concentration in the ruminal fluid and tended to increase dry matter and organic matter digestibility compared with the control. During the grain challenge, rumen endotoxin concentration increased over time and was higher for cows fed the HS diets compared with those fed LS diets. However, response variables related to inflammation were not affected by the grain challenge. However, serum haptoglobin, lipopolysaccharide-binding protein, and serum amyloid-A concentrations were greater for cows fed butyrate with the LS diet, but not for those fed the HS diet. These results indicate that butyrate supplementation may increase plasma GLP-2 concentration for cows fed HS diets, and total-tract digestibility regardless of dietary starch content. However, butyrate supplementation did not mitigate inflammation in this study.