EFFECTS OF BEEF SEMEN AND BEEF EMBRYO STRATEGIES ON PROFITABILITY: Economics of using beef semen and beef in vitro produced embryo transfer in Jersey herds.

Dairy herds have adopted sexed semen (SS) and beef semen (BS) to control heifer inventory and increase calf sales revenue. Beef in vitro-produced embryo transfer (beef IVP-ET) may be an alternative to increase calf sales revenue. Besides, raising those Jersey beef crossbred and/or pure beef animals in a dairy system may be a new source of revenue. We aimed to evaluate breed strategies combining dairy conventional semen (CS), SS, BS, and beef IVP-ET on herd dynamics and profitability by marketing those animals with one-day-old or raising them to 180 kg. A Markov chain model was developed to maximize the profitability of Jersey herds by changing the number of dairy heifers sold at birth and the culling rate of 3rd and greater parity cows. The model presents inputs on the reproductive and productive performance of heifers and cows over time. The last year's data (year 10 - steady state) was used to calculate accrual operational cost and revenue per cow per year. We varied the breeding strategy by breeding order and parities, the embryo transfer cost ($85 or $170), the pure beef calf market price ($200 or $300), and by marketing Jersey-beef and pure beef animals with one-day-old or raising them to 180 kg. A total of 8 scenarios + default scenario were simulated. Overall, the proportion of SS use was 47.3 ± 0.6%. For the scenarios replacing all CS breedings with BS breedings, the proportion of CS and BS used was 52.3 ± 0.6. When beef IVP-ET was used, the percentage of BS and beef IVP-ET used was 22.4 ± 0.1% and 31.0 ± 0.1%, respectively. We observed that when we compared SS:BS with the default scenario, the production of purebred Jersey male calves was reduced by 83.5%, and profit/cow per year was increased from $113.5 to $203.3 with SS:BS. When a beef IVP-ET of $85 per transfer was used (scenarios 2 and 3), profit/cow per year was $145.5 and $176.2 for a pure-beef calf price of $200 and $300, respectively. In scenario 4, with a beef IVP-ET cost of $170, the lowest profit ($52.9 per cow per year) was found when marketing one-day-old pure-beef calves at $200. The highest profit was achieved for scenario raising the Jersey-beef crossbred animals to 180 kg ($232.9, scenario 6), followed by scenario 7 ($222.9, SS:BS:IVP-ET) with an embryo transfer cost of $85. Under the current market conditions, combining SS and BS in the reproductive program was a feasible economic opportunity for Jersey herds, yielding the highest net return. The adoption of beef IVP-ET in a reproductive program can potentially increase profit/cow per year, but its profitability will depend on the beef IVP-ET pregnancy cost, the pure-beef market price, calf performance, and the herd reproductive performance. In conclusion, raising the Jersey-beef crossbred calves may be a profitable strategy, and dairy producers need to evaluate the best option to invest in since it will take an extra risk to produce high-quality animals to the market.

Association of morbidity, mortality, and average daily gain with transfer of passive immunity in dairy-beef crossbred calves up to 60 d of life.

Adequate transfer of passive immunity (TPI) is a cornerstone for a proper health status of calves. In the literature, there is limited information on the prevalence of failure of TPI in dairy-beef crossbred calves and its impact on morbidity, mortality, and average daily gain (ADG) during the preweaning period. Therefore, this study aimed to evaluate the association between TPI with morbidity, mortality, and ADG in pre-weaned dairy-beef crossbred calves. A total of 1,055 newborn dairy-beef crossbred calves were enrolled upon arrival at a calf-raising facility in California from January to August 2021. Farm of origin, genetic breed group, sex, and body weight were recorded upon arrival. Blood was collected at 24 ± 1 h post-arrival to evaluate serum IgG concentration, serum total protein (TP), and packed cell volume. Morbidity (diarrhea and respiratory treatment records) and mortality were recorded daily until 60 d of life. Calves were grouped into 2 genetic breed groups: Holstein x Beef (Ho x Be, 49.6%) and Jersey × Beef crossbred calves (Je × Be, 50.4%). Descriptive statistics and Cox proportional hazard models were created to evaluate the association of TPI categories for serum IgG (TPI-IgG: poor: < 10.0 g/L, fair: 10.0 - 17.9 g/L, good: 18.0 - 24.9 g/L, and excellent: ≥ 25.0 g/L) and TP (TPI-TP: poor: < 5.1 g/dL, fair: 5.1 - 5.7 g/dL, good: 5.8 - 6.1 g/dL, and excellent: ≥ 6.2 g/dL), sex, and genetic breed group with morbidity and mortality. Additionally, a mixed linear regression was performed to evaluate the association of sex, genetic breed group, and TPI categories with ADG. Overall morbidity and mortality were 84.8% (n = 895) and 2.5% (n = 26). Calves classified as TPI-IgG excellent were associated with the lowest (43.2% less) hazard of being treated compared with TPI-IgG poor calves. For mortality, dairy-beef crossbred calves with TPI-IgG excellent were associated with a reduction of 82.0% in the hazard of dying compared with TPI-IgG poor. The TPI-IgG poor and TPI-IgG fair calves were associated with a decreased ADG of 101.0 and 98.8 g/d, respectively, in comparison with TPI-IgG good calves. Average daily gain of TPI-IgG good and TPI-IgG excellent calves were not different. In our study, dairy-beef crossbred calves enrolled may have endured challenging conditions that increased morbidity. This reinforces the importance of high IgG levels to decrease morbidity and mortality and maximize ADG in dairy-beef crossbred calves raising systems. Further research should evaluate the long-term effects of TPI categories on the health and performance of dairy-beef crossbred calves.

Unveiling unstable non-acid incidence in Holstein cows fed with corn silage or sugarcane.

We aimed to evaluate the incidence of unstable non-acid milk (UNAM) in cows fed either sugarcane or corn silage. Second, we aimed to evaluate the effect of daily variation (d 1 to 4) and alcohol grades (72, 78, and 80%) on UNAM incidence. The experiment was conducted as a split-plot crossover design, with 2 periods and 2 roughage types (sugarcane or corn silage). Thirteen multiparous Holstein cows with an average of 281 ± 29 d in milk were randomly distributed into 2 diets. Individual blood (analysis of total proteins, albumin, urea, calcium, phosphorus, magnesium, iron, chloride, glucose, and lactate) and milk samples (analysis of protein, fat, lactose and total solids, somatic cell count, and characterization of the protein profile) were collected during the last 4 d of each period. For UNAM identification, the alcohol test was conducted in milk samples at 4°C; specifically, if the sample presented the formation of clots, this would be noted as positive for UNAM. In addition, the Dornic acidity analysis was performed in the same samples to evaluate the true milk acidity. The use of sugarcane and higher degrees of alcohol were associated with increased UNAM. We observed no daily variation in UNAM. Nevertheless, we found no roughage type effect on the variables most commonly associated with UNAM, such as changes in salts in the casein micelle and, consequently, the zeta potential and the κ-casein (CN) fraction. The Pearson correlation analysis showed that the zeta potential and the concentrations of αS2-CN, blood ionic calcium, lactate, and glucose increased as the incidence of UNAM increased, showing a positive correlation among these variables. In contrast, the concentrations of lactose, phosphorus, and potassium decreased as UNAM increased, presenting a negative correlation. This study brought important discoveries to unveil why cows manifest UNAM. For instance, higher alcohol grades and cows fed with sugarcane had increased the incidence of UNAM. Additionally, animals with a higher incidence of UNAM (sugarcane-fed cows) were related to increased ionic calcium and glucose and changes in milk protein profile, with lower levels of BSA, ß-CN, and α-lactalbumin and greater αS1-CN content, all of which were correlated with UNAM. Nonetheless, this trial also provides evidence for the need for further studies to better understand the physiological mechanisms that directly affect the stability of milk protein.

Performance and feeding behavior of Holstein and Holstein × Gyr crossbred heifers grazing temperate forages.

This study aimed to investigate the difference between Holstein and Holstein × Gyr breeds on feeding behavior and performance of heifers grazing temperate pasture. The experiment was carried out in 89 days, split into 14 days of adaptation, and 3 periods of 25 days. Two treatments were used: Holstein (HOL; n = 7) and Holstein × Gyr (HG; n = 7). Heifers grazed a consortium of ryegrass and bristle oats and were supplemented individually daily with cornmeal at 0.33% of body weight plus 5 kg/day of corn silage. For 3 consecutive days, feeding behavior was observed for individual animals from direct visual observation recording at 10-min intervals. The digestibility trial was performed on day (d) 16 to d24 of each period. Body measurements and weight were taken at d0 and at d23, 24, and 25 of each period. Grazing duration, grazing frequency, and bite rate were greater for HOL than those for HG. Rumination characteristics, intake, digestibility, and body measurements were not affected by breed. Breeds had differences in grazing characteristics, but they did not influence performance or intake parameters. Therefore, HOL and HG heifers managed under temperate pasture in tropical countries have similar performances.

Determination of energy and protein requirements of preweaned dairy calves: A multistudy approach.

The first studies concerning nutrient requirements for preweaned dairy calves were from the 1920s and 1930s; however, few studies were published in the following decades. We aimed to determine energy and protein requirements of preweaning Holstein and Holstein × Gyr dairy calves in a multistudy meta-regression. We used a database composed of individual measurements of 166 preweaned male calves (138 submitted to treatments and 28 used as the reference group) from 4 studies that used the methodology of comparative slaughter. Animals with less than 15/16 of Holstein genetic composition were considered crossbred Holstein × Gyr, whereas other animals were considered Holstein. Net energy requirements for maintenance (NEM) were determined by the regression between heat production and metabolizable energy intake (MEI). The metabolizable energy requirements for maintenance were calculated by the iterative method, and the efficiency of use of metabolizable energy for maintenance was obtained by NEM divided by the metabolizable energy requirements for maintenance. Net energy requirements for gain (NEG) were estimated using a regression of the retained energy (RE) as a function of empty body weight (EBW) and empty body gain (EBG). The efficiency of use of metabolizable energy for gain was estimated by the regression of RE as a function of MEI, but with partitioning the MEI into MEI from liquid feed and MEI from starter feed. Additionally, the effect of a liquid feed (milk or milk replacer) was tested on the slope of the regression. The metabolizable protein requirements for maintenance (MPM) were estimated using the intercept of the regression between the metabolizable protein intake (MPI) and average daily gain. The MPM was determined as the ratio between the intercept and the metabolic body weight. Net protein requirements for gain (NPG) were estimated by the regression between retained protein, EBG, and RE. The efficiency of use of metabolizable protein for gain was estimated by the regression of the retained protein as a function of MPI, but with partitioning the MPI into MPI from liquid feed and MPI from starter feed. Additionally, the effect of a liquid feed (milk or milk replacer) was tested on the regression slope. Breed did not influence any of the nutrient requirements' estimates. The NEM was estimated as 70.2 kcal/metabolic body weight per day. The efficiency of use of metabolizable energy for maintenance observed was 66%. The NEG was estimated by the equation NEG = 0.0901 × EBW0.75 × EBG0.9539. The efficiency of use of metabolizable energy for gain was estimated as 57.6, 49.3, and 41.2% for milk, milk replacer, and starter feed, respectively. The MPM was estimated as 4.22 g/EBW0.75 per day, and the NPG was determined by the equation: NPG = 30.06 × EBG + 70.98 × RE. The efficiency of use of metabolizable protein for gain was estimated as 71.9, 59.2, and 44.4% for milk, milk replacer, and starter feed, respectively. We concluded that no differences were observed in energy and protein requirements between Holstein and Holstein × Gyr crossbred cows. The efficiencies of use of metabolizable energy and protein are greater for milk when compared with milk replacer and starter feed. Therefore, we propose that the equations generated herein should be used to estimate energy and protein requirements of preweaned Holstein and Holstein × Gyr crossbred dairy calves raised under tropical conditions.

Body composition changes of crossbred Holstein × Gyr cows and conceptus during pregnancy.

This study aimed to evaluate the effects of plane of nutrition and advancing days of pregnancy (DP) on maternal body composition and fetal development. Differing planes of nutrition were established by 2 feeding regimens (FR): ad libitum (AL) or maintenance (MA). Sixty-two nonlactating multiparous Holstein × Gyr cows with average body weight of 480 ± 10.1 kg and an age of 5 ± 0.5 yr were used. Cows were divided into 3 groups: pregnant (n = 44), nonpregnant (n = 12), and baseline reference cows (n = 6). The 56 pregnant and nonpregnant cows were randomly allocated into 2 different FR: AL or MA. Cows fed at MA received 1.15% of their body weight on a dry matter (DM) basis, receiving corn silage and a concentrate-based diet at a ratio of 93:7 on a DM basis. Reference group cows were slaughtered at the beginning of the experimental period to estimate body composition and empty body weight. To evaluate the effects of DP, pregnant and nonpregnant animals were slaughtered at d 140, 200, 240, and 270 of gestation. Feeding regimen affected maternal tissue composition. Days of pregnancy affected fresh weight (FW), DM, and energy content, but no differences were observed for crude protein (CP) and ether extract (EE) because of DP. Feeding regimen affected mammary gland components (CP, EE, and energy content), but not fresh or dry weights. Days of pregnancy influenced almost all mammary gland components except energy content. Regarding the uterus, FR affected only fresh and dry weights; however, DP affected every uterus component measured. The only interaction between FR and DP in this study was observed for placental FW. Cows fed AL on d 270 presented the same placental FW as cows at MA and AL on d 200 and 240. Further, pregnant cows fed at MA on d 270 had greater placental FW than cows fed AL at this day. Days of pregnancy, but not FR, influenced the composition of fetal fluids in pregnant cows. Finally, cows fed at MA had greater FW for the fetus than cows fed AL; however, fetus composition changed over DP. The FW, DM, EE, and energy content increased until d 270, but CP decreased. In conclusion, the novelty of our data presents how changes due to FR and DP occur in maternal tissues and the conceptus.

Compositional and structural dynamics of the ruminal microbiota in dairy heifers and its relationship to methane production.

BACKGROUND: Heifers emit more enteric methane (CH4 ) than adult cows and these emissions tend to decrease per unit feed intake as they age. However, common mitigation strategies like expensive high-quality feeds are not economically feasible for these pre-production animals. Given its direct role in CH4 production, altering the rumen microbiota is another potential avenue for reducing CH4 production by ruminants. However, to identify effective microbial targets, a better understanding of the rumen microbiota and its relationship to CH4 production across heifer development is needed. RESULTS: Here, we investigate the relationship between rumen bacterial, archaeal, and fungal communities as well as CH4 emissions and a number of production traits in prepubertal (PP), pubertal (PB), and pregnant heifers (PG). Overall, PG heifers emitted the most CH4 , followed by PB and PP heifers. The bacterial genus Acetobacter and the archaeal genus Methanobrevibacter were positively associated, while Eubacterium and Methanosphaera were negatively associated with raw CH4 production by heifers. When corrected for dietary intake, both Eubacterium and Methanosphaera remained negatively associated with CH4 production. CONCLUSION: We suggest that Eubacterium and Methanosphaera represent likely targets for CH4 mitigation efforts in heifers as they were negatively associated with CH4 production and not significantly associated with production traits. © 2018 Society of Chemical Industry.

Short-term effects of soybean oil supplementation on performance, digestion, and metabolism in dairy cows fed sugarcane-based diets.

We aimed to quantify the productive and metabolic responses, and digestive changes in dairy cows fed various concentrations of soybean oil (SBO) in high-concentrate, sugarcane-based diets. Eight rumen-cannulated multiparous Holstein cows in mid lactation (574 ± 19.1 kg of body weight and 122 ± 6.9 d in milk), averaging 22.5 ± 1.22 kg/d of milk were assigned to replicated 4 × 4 Latin squares. The experimental period lasted 21 d as follows: 14 d for adaptation, followed by a sampling period from d 15 to 21. The diets were formulated with increasing concentrations of SBO [% of dry matter (DM)]: control (0%), low (LSBO; 1.57%), medium (MSBO; 4.43%), and high (HSBO; 7.34%). Dry matter intake decreased quadratically in response to SBO addition. The greatest decrease in DM intake was observed in MSBO and HSBO diets. Both milk and energy-corrected milk yield were quadratically affected by the SBO inclusion, with a slight decrease up to MSBO and substantial decrease in the HSBO diet. The milk fat concentration linearly decreased from 3.78% in the control to 3.50% in the HSBO diet. The potentially digestible neutral detergent fiber digestibility in the rumen decreased from 55.7% in the control to 35.2% in the HSBO diet. The fractional rate of digestion of potentially digestible neutral detergent fiber in the rumen decreased linearly from 3.13 to 1.39%/h from the control to HSBO diet. The fractional rate of indigestible neutral detergent fiber passage in the rumen was quadratically affected, with the lowest value (2.25%/h) for the HSBO diet. Rumen pH increased from 6.42 to 6.67, and ammonia nitrogen decreased from 28.1 to 21.4 mg/dL, in the control and HSBO diets, respectively. Rumen volatile fatty acids decreased quadratically, with the greatest decrease observed in MSBO and HSBO diets. Serum concentrations of glucose, fatty acids, and ß-hydroxybutyrate were unaffected by SBO inclusion. However, serum concentrations of total cholesterol and high- and low-density lipoproteins linearly increased with increasing concentrations of SBO in the diet. Inclusion of SBO at concentrations from 4.43 to 7.34% of the diet DM decreased DM intake, energy-corrected milk production, fiber digestibility, and rumen fermentation and was thus not recommended. Soybean oil supplementation at 1.57% of the diet DM proved to be a safe concentration for dairy cows fed high-concentrate diets with sugarcane as the sole forage.

Mammary gland development of dairy heifers fed diets containing increasing levels of metabolisable protein: metabolisable energy.

This study was conducted to evaluate the development of the mammary gland in Holstein heifers subjected to different dietary metabolisable protein (MP): metabolisable energy (ME) ratios. Twenty-five Holstein heifers (initial body weight (BW) 213±13·5 kg and initial average age 7·8±0·5 months) were divided into five treatments. The treatments were designed to provide MP:ME ratios equal to 33, 38, 43, 48, and 53 g of MP per Mcal of ME. All diets were formulated to have the same energy content (2·6 Mcal ME/kg dry matter). Actual MP:ME ratios were 36·2, 40·2, 46·2, 47·1, and 50·8 g MP/Mcal ME. The experiment was conducted in a randomised block design, while considering initial BW as a blocking factor to evaluate pre- and post-pubertal periods. Block effect was not observed for all variables evaluated; hence it was considered that the diets had the same influence both on pre- and post-pubertal phases. Dry matter and nutrient intake did not change between treatments, excepting protein intake and digestibility. Serum concentrations of insulin-like growth factor 1 increased linearly across treatments. Changes in the pixel brightness of mammary gland ultrasound images, which are associated with lipid content, were significantly influenced by MP:ME ratios in the diet of heifers that were subjected to accelerated growth rates. It is not recommended to use diets of less than 38 g MP/Mcal ME in diets to heifers allowed to gain more than 1 kg/d.

Macromineral requirements for maintenance and growth in male and female hair sheep.

A better understanding of the nutritional requirements of sheep, especially in terms of minerals, is crucial for improving production. We estimated the net requirements for Ca, P, K, Mg, and Na for gain (NCag, NPg, NKg, NMgg, and NNag) and maintenance (NCam, NPm, NKm, NMgm, and NNam) in male and female hair sheep. Six datasets with 248 individual records of hair sheep (139 non-castrated males, 75 castrated males and 34 females) were used to estimate the net macromineral requirements for gain. To estimate the net macromineral requirements for maintenance, 52 observations (26 non-castrated and 26 castrated males) were used. A meta-analytical approach was applied, using non-linear mixed effects models and the study as a random effect. Based on information criteria for model selection, heterogeneous variance functions were more likely to describe mineral requirements with a low level of model selection uncertainty. The adopted criteria allowed the choice of the best models to represent the macromineral requirements. The chosen models explained the observed variability in the sex, and the choices were based on a low level of uncertainty (w ≥ 0.90). Irrespective of sex, NCag and NPg decreased with increasing BW from 10 to 30 kg and average daily gain (ADG) of 150 g/day, ranging from 1.71-1.38; 1.83-1.57; 1.82-1.51 of Ca and 0.86-0.66; 0.92-0.78; 0.92-0.75 of P for non-castrated males, castrated males, and females, respectively. The NKg remained constant, with mean values of 0.26 g/day. The NNag range was 0.17 to 0.14 g/day for non-castrated males, 0.20 to 0.25 g/day for females, and constant (0.18 g/day) for castrated males with an increase in BW from 10 to 30 kg and an ADG of 150 g/day. Macromineral requirements for maintenance (mg/kg BW) and retention (%) were 23.70 and 54.30 for Ca, 25.33 and 79.80 for P, 11.74 and 5.00 for K, 2.63 and 8.50 for Mg, and 7.01 and 8.10 for Na for males. The International Committees did not provide inferences about the sex influence on mineral requirements. Our study indicates that sex is one factor that influences the macromineral requirements for gain. The information generated in this study can be used to optimize the mineral management of hair sheep in the growing phase in tropical regions.

Improving the accuracy of beef cattle methane inventories in Latin America and Caribbean countries.

On-farm methane (CH4) emissions need to be estimated accurately so that the mitigation effect of recommended practices can be accounted for. In the present study prediction equations for enteric CH4 have been developed in lieu of expensive animal measurement approaches. Our objectives were to: (1) compile a dataset from individual beef cattle data for the Latin America and Caribbean (LAC) region; (2) determine main predictors of CH4 emission variables; (3) develop and cross-validate prediction models according to dietary forage content (DFC); and (4) compare the predictive ability of these newly-developed models with extant equations reported in literature, including those currently used for CH4 inventories in LAC countries. After outlier's screening, 1100 beef cattle observations from 55 studies were kept in the final dataset (∼ 50 % of the original dataset). Mixed-effects models were fitted with a random effect of study. The whole dataset was split according to DFC into a subset for all-forage (DFC = 100 %), high-forage (94 % ≥ DFC ≥ 54 %), and low-forage (50 % ≥ DFC) diets. Feed intake and average daily gain (ADG) were the main predictors of CH4 emission (g d-1), whereas this was feeding level [dry matter intake (DMI) as % of body weight] for CH4 yield (g kg-1 DMI). The newly-developed models were more accurate than IPCC Tier 2 equations for all subsets. Simple and multiple regression models including ADG were accurate and a feasible option to predict CH4 emission when data on feed intake are not available. Methane yield was not well predicted by any extant equation in contrast to the newly-developed models. The present study delivered new models that may be alternatives for the IPCC Tier 2 equations to improve CH4 prediction for beef cattle in inventories of LAC countries based either on more or less readily available data.

Use of Heating Methods and Xylose to Increase Rumen Undegradable Protein of Alternative Protein Sources: 1) Peanut Meal.

Peanut meal has an excellent total protein content but also has low rumen undegradable protein (RUP). High-performance ruminants have high RUP requirements. We aimed to evaluate the effects of processing peanut meal with an autoclave and conventional and microwave ovens, with and without using xylose on its ruminal kinetics degradation parameters and intestinal digestibility (ID). In situ studies were conducted to determine dry matter (DM) and crude protein (CP) rumen degradation kinetics. In vitro studies were conducted to evaluate intestinal digestibility (ID). The control treatment had a greater fraction A for DM and CP than peanut meals processed with an autoclave or conventional oven. The control had greater kd for CP compared with the microwave. The addition of xylose decreased fraction A, the degradation rate of fraction B (kd) and RUP, and increased the protein B fraction of autoclaved peanut meal. We observed a decrease in effective degradability (ED) and increased RUP for processed treatments in all experiments compared with the control. Processing methods did not affect the protein ID of autoclaved peanut meal compared to the control. An interaction between xylose and heating time was observed, where increasing heating time linearly reduced the ID of xylose-untreated treatments. Overall, these results suggest that the tested methods effectively increased the RUP content of peanut meal.

Use of Heating Methods and Xylose to Increase Rumen Undegradable Protein of Alternative Protein Sources: 2) Cottonseed Meal.

The ruminal kinetics of protein sources may be changed by heat and sugar treatments. Thus, these processing methods may be used as alternatives to increase beef-cattle diets' rumen undegradable protein (RUP). We aimed to evaluate the effects of processing cottonseed meals with autoclave, conventional, and microwave ovens, with and without using xylose, on the ruminal kinetics degradation parameters and intestinal digestibility (ID). In situ studies were conducted, and each sample was incubated in the rumen to determine dry matter (DM) and crude protein (CP) rumen degradation kinetics. In vitro studies were also conducted to evaluate ID. The control treatment had a greater soluble fraction for DM and CP than processed cottonseed meals (p < 0.05). The addition of xylose decreased both DM and CP water-soluble fractions (fraction A) of cottonseed meal heated in a conventional oven (p < 0.05). Compared to the control, we observed a decrease in effective degradability and increased RUP for all processed methods (p < 0.05). Furthermore, conventional and microwave ovens showed greater ID than the control. Moreover, xylose-treated groups heated in the autoclave and conventional ovens had greater ID than xylose-untreated cottonseed meal. Under these experimental conditions, cottonseed RUP was increased by the evaluated processing methods.

Prediction of enteric methane production and yield in dairy cattle using a Latin America and Caribbean database.

Successful mitigation efforts entail accurate estimation of on-farm emission and prediction models can be an alternative to current laborious and costly in vivo CH4 measurement techniques. This study aimed to: (1) collate a database of individual dairy cattle CH4 emission data from studies conducted in the Latin America and Caribbean (LAC) region; (2) identify key variables for predicting CH4 production (g d-1) and yield [g kg-1 of dry matter intake (DMI)]; (3) develop and cross-validate these newly-developed models; and (4) compare models' predictive ability with equations currently used to support national greenhouse gas (GHG) inventories. A total of 42 studies including 1327 individual dairy cattle records were collated. After removing outliers, the final database retained 34 studies and 610 animal records. Production and yield of CH4 were predicted by fitting mixed-effects models with a random effect of study. Evaluation of developed models and fourteen extant equations was assessed on all-data, confined, and grazing cows subsets. Feed intake was the most important predictor of CH4 production. Our best-developed CH4 production models outperformed Tier 2 equations from the Intergovernmental Panel on Climate Change (IPCC) in the all-data and grazing subsets, whereas they had similar performance for confined animals. Developed CH4 production models that include milk yield can be accurate and useful when feed intake is missing. Some extant equations had similar predictive performance to our best-developed models and can be an option for predicting CH4 production from LAC dairy cows. Extant equations were not accurate in predicting CH4 yield. The use of the newly-developed models rather than extant equations based on energy conversion factors, as applied by the IPCC, can substantially improve the accuracy of GHG inventories in LAC countries.

Maintenance and Growth Requirements in Male Dorper × Santa Ines Lambs.

The aim of this study was to estimate the energy and protein requirements for maintenance and growth of lambs. A total of 35 crossbreed Dorper × Santa Ines lambs [31 ± 1.28 kg of initial body weight (BW) and 4 months old] were distributed in a completely randomized design with three treatments groups (ad libitum, 30 and 60% of feed restriction). Five lambs were slaughtered at the beginning of the experimental trial as a reference group to estimate the initial empty BW (EBW) and body composition. When the animals of the ad libitum treatment reached a BW average of 47.2 kg, at day 84 of trial, all lambs were slaughtered. The feed restriction promoted reduction in body fat (P < 0.001) and energy concentration (P < 0.001), while protein showed a quadratic response (P = 0.05). The equations obtained for NEg and NPg requirements were 0.2984 × EBW0.75 × EBWG0.8069 and 248.617 × EBW-0.15546, respectively. The net energy (NEm) and protein (NPm) for maintenance were 71.00 kcal/kg EBW0.75/day and 1.76 g/kg EBW0.75/day, respectively. In conclusion, the NEg and NPg requirement for lambs with 30 kg of BW and 200 g of average daily gain (ADG) were 0.736 Mcal/day and 24.38 g/day, respectively. Our findings indicate that the NEm for crossbreed Dorper × Santa Ines lambs is similar to those recommended by the international committees; however, we support the hypothesis that the requirements for gain are lower.

Effects of Feeding Level and Breed Composition on Intake, Digestibility, and Methane Emissions of Dairy Heifers.

The dairy Nutrients Requirements of Cattle (NRC) was developed using data from purebred Holsteins and it might not accurately predict the performance of crossbred cattle. Our objectives were to evaluate the effects of two feeding levels (FLs) and three breed compositions (BCs) on nutrient intake, digestibility, performance, and methane (CH4) emissions of prepubertal dairy heifers. We used thirty-six heifers from three BCs: purebred Holstein (H), purebred Gyr (G), and F1 Holstein × Gyr (HG). Each BC had 12 animals and the experiment was designed as twelve incomplete three by three Latin squares, in a factorial arrangement three by two, with three BCs and two FLs (400 and 800 g/day). Total tract nutrient digestibility was determined using total fecal collection and DMI was individually measured. The data were analyzed using the PROC MIXED in SAS. Dry matter intake of all nutrients increased from the medium to high feeding level and the nutrients digestibility coefficients did differ among BCs. Achieved body weight gain in the medium FL treatment was greater than those predicted using the NRC, suggesting that crossbred and Gyr heifers have similar performance to Holsteins. Breed composition does not influence body weight gain of confined dairy heifers, but Holstein heifers fed a medium FL had higher feed efficiency and reduced CH4 emissions intensity.

Supplementation strategies affect the feed intake and performance of grazing replacement heifers.

The literature lacks studies investigating the performance of supplemented replacement heifers grazing on intensively managed warm-season pasture. Our objective was to evaluate the effects of supplement composition (energetic or protein) on the performance, muscle development, thermogenisis, nutrient intake, and digestibility of replacement Holstein heifers grazing Mombaça grass. Eighteen Holstein heifers with an average age and initial body weight (BW) of 12.57 ± 2.54 mo and 218.76 ±47.6 kg, respectively, were submitted to a randomized block design, with six replicates on a rotational grazing system of Panicum maximum cv. Mombaça pasture. Treatments were: control (CON; mineral salt ad libitum); energy supplement (ENE; corn meal as supplement, 8% CP and 3.78 Mcal/kg DE); and protein supplement (PRO; corn and soybean meal, 25% CP and 3.66 Mcal/kg DE). Supplements were individually fed at 0.5% BW. The experiment lasted 120 days, subdivided into three periods. Titanium dioxide and indigestible neutral detergent fiber (iNDF) were used to estimate the intakes and digestibility of the nutrients. BW, wither height, thoracic circumference, body length, and ultrasound of ribeye fat thickness measurements were taken once per period. Body condition score (BCS) was assessed twice during the experiment. The MIXED procedure of SAS, including period as a repeated measure, was used and significance was declared at P ≤ 0.05. Dry matter intake (DMI), CP intake (CPI) and DE intake were greater in heifers fed PRO compared to CON and ENE. Heifers supplemented with ENE had the lowest DMI. Treatment affected pasture intake/BW; it was similar between PRO and CON heifers, and lower for the ENE treatment. A treatment × period interaction was observed for NDF intake (%BW), in which heifers fed PRO and CON had the greatest NDF intake and ENE had the lowest. The digestibility of DM was the greatest in PRO-supplemented heifers and the lowest in CON heifers. Heifers fed ENE had decreased CP digestibility compared to PRO and CON heifers. Average daily gain (ADG) and thoracic circumference gain were greatest in the PRO treatment. BCS was greater in PRO compared to CON and ENE heifers. Supplementing Holstein heifers at 0.5% BW using PRO supplementation resulted in better animal performance, primarily greater ADG, than feeding ENE or not supplementing (CON). In conclusion, our results indicate that dairy heifers should be fed a protein supplement when grazing intensively managed Mombaça grass pasture.

Effect of selected feed additives to improve growth and health of dairy calves.

The aim was to evaluate the effect of different feed additives on intake, performance, and fecal consistency index (FCI) of dairy calves from 6-60 d of age and its residual effect 15 d after weaning. Fifty Holstein calves (38 ± 1.0 kg BW) were fed 5 L/d of milk plus starter feed until weaning, and corn silage and concentrate after weaning. The treatments were: control (CON), monensin (MON; 30 mg/kg of starter), probiotic E. faecium (PROB; 70 mg/kg of starter), essential oils (EO; 300 mg/kg of starter), or PROB + EO (EOPROB). Fecal score and dry matter intake (DMI) were measured daily, and animals were weighed every 15 d. A DNA extraction from feces was performed to identify the presence of microorganisms (E. coli, Hafnia, Shiguella, Lactobacillus spp, Enterococcus spp, and Enterococcus faecium NCIMB 10415) by PCR. Two 72-h digestibility trials were performed at days 20-28 and 50-56, by total fecal collection. The DMI before weaning was greater for EO (903.0 g/d) compared with MON (794.3 g/d) and EOPROB (783.1 g/d). The FCI decreased during pre-weaning for EO and MON. Average daily gain (ADG) and feed efficiency (FE) did not differ among treatments before weaning. After weaning, DMI and FCI did not differ among treatments. The EO had greater ADG (917.5 g/d) compared with CON (615.8 g/d) and PROB (592.6 g/d). The FE improved with EO (0.72 g/g) over CON (0.36 g/g), MON (0.49 g/g), and PROB (0.36 g/g). The PCR results showed absence of E. faecium NCIMB 10415 in animals fed PROB and CON. Animals fed PROB had greater intake of CP and NDF than animals fed EOPROB. The EO can be added to the dairy calf ration to improve fecal score and increase DMI. The pre-weaning FCI decrease with MON and increase with PROB.

Effect of Pre-weaning Diet on the Ruminal Archaeal, Bacterial, and Fungal Communities of Dairy Calves.

At birth, calves display an underdeveloped rumen that eventually matures into a fully functional rumen as a result of solid food intake and microbial activity. However, little is known regarding the gradual impact of pre-weaning diet on the establishment of the rumen microbiota. Here, we employed next-generation sequencing to investigate the effects of the inclusion of starter concentrate (M: milk-fed vs. MC: milk plus starter concentrate fed) on archaeal, bacterial and anaerobic fungal communities in the rumens of 45 crossbred dairy calves across pre-weaning development (7, 28, 49, and 63 days). Our results show that archaeal, bacterial, and fungal taxa commonly found in the mature rumen were already established in the rumens of calves at 7 days old, regardless of diet. This confirms that microbiota colonization occurs in the absence of solid substrate. However, diet did significantly impact some microbial taxa. In the bacterial community, feeding starter concentrate promoted greater diversity of bacterial taxa known to degrade readily fermentable carbohydrates in the rumen (e.g., Megasphaera, Sharpea, and Succinivribrio). Shifts in the ruminal bacterial community also correlated to changes in fermentation patterns that favored the colonization of Methanosphaera sp. A4 in the rumen of MC calves. In contrast, M calves displayed a bacterial community dominated by taxa able to utilize milk nutrients (e.g., Lactobacillus, Bacteroides, and Parabacteroides). In both diet groups, the dominance of these milk-associated taxa decreased with age, suggesting that diet and age simultaneously drive changes in the structure and abundance of bacterial communities in the developing rumen. Changes in the composition and abundance of archaeal communities were attributed exclusively to diet, with more highly abundant Methanosphaera and less abundant Methanobrevibacter in MC calves. Finally, the fungal community was dominated by members of the genus SK3 and Caecomyces. Relative anaerobic fungal abundances did not change significantly in response to diet or age, likely due to high inter-animal variation and the low fiber content of starter concentrate. This study provides new insights into the colonization of archaea, bacteria, and anaerobic fungi communities in pre-ruminant calves that may be useful in designing strategies to promote colonization of target communities to improve functional development.

Performance of lactating cows fed sugarcane silage treated with microbial additives

Background: No studies have been conducted evaluating sugarcane silage associated with both Lactobacillus plantarum and Pediococcus pentosaceus for lactating dairy cows. Objective: To evaluate diets containing different roughages with and without microbial inoculants on intake, digestibility and milk yield of medium-producing cows. Methods: A total of 15 Holstein cows distributed into a randomized block design were used. Dietary treatments were: 1) a corn silage-based diet (CS), 2) a fresh sugarcane-based diet (SC), 3) a sugarcane silage ensiled without inoculant (SS), 4) sugarcane silage ensiled with Lactobacillus buchneri (SSLB), and 5) sugarcane silage ensiled with Lactobacillus plantarum and Pediococcus pentosaceus (SSLP). Results: Digestible organic matter intake (DOMI) was lower (p<0.05) in cows fed SSLB (9.77 kg day-1) when compared with cows fed CS (13.29 kg day-1) and SSLP (12.42 kg day-1). Ensiling of sugarcane increased intake of neutral detergent fiber (NDF) compared to SC (mean of 6.00 kg day-1 versus 4.97 kg day-1; p<0.05). Dry matter digestibility was greater (p<0.05) in CS (77.80%) compared with diets based on sugarcane silage, whereas NDF digestibility was lower for treatments with sugarcane (p<0.05). Milk yield was similar among CS (27.99 kg), SC (25.59 kg), and silages with additives (25.47 and 27.07 for SSLB and SSLP, respectively). Cows fed CS produced more fat-corrected milk (25.89 kg) than those fed sugarcane-based diets (p<0.05). Conclusions: Fresh sugarcane or sugarcane silage with additives can be used as a roughage source for dairy cows producing up to 23.43 kg d-1 fat-corrected milk, considering the total diet is properly balanced.

Antecedentes: No existen estudios que evalúen la adición de Lactobacillus plantarum y Pediococcus pentosaceus en el ensilaje de caña de azúcar para vacas lactantes. Objetivo: Evaluar dietas con diferentes forrajes y ensilajes con y sin inoculantes microbianos sobre el consumo, digestibilidad y producción lactea de vacas de mediana producción. Metodología: Quince vacas Holstein se distribuyeron en un diseño de bloques al azar. Los tratamientos fueron: 1) dieta con ensilaje de maíz (CS), 2) dieta con caña de azúcar fresca (SC), 3) dieta con ensilaje de caña sin inoculantes (SS), 4) dieta con ensilaje de caña de azúcar ensilada con Lactobacillus buchneri (SSLB), y 5) dieta con ensilaje de caña de azúcar ensilada con Lactobacillus plantarum y Pediococcus pentosaceus (SSLP). Resultados: El consumo de materia orgánica digestible fue menor (p<0,05) en la dieta SSLB (9,77 kg day-1) en comparación con CS (13,29 kg dia-1) y SSLP (12,42 kg dia-1). El ensilaje de caña de azúcar promovió un mayor consumo de fibra detergente neutra (NDF) en comparación con SC (promedio de 6,00 kg dia-1 versus 4,97 kg dia-1; p<0,05). La digestibilidad de la materia seca fue mayor (p<0,05) para la dieta CS (77,80%) en comparación con las dietas con ensilaje de caña de azúcar, mientras que la digestibilidad de la NDF fue menor para las dietas a base de caña de azúcar (p<0,05). La producción de leche fue similar entre CS (27,99 kg), SC (25,59 kg) y ensilajes con aditivos (25,47 y 27,07 para SSLB y SSLP, respectivamente). Las vacas alimentadas con ensilaje de maíz produjeron más leche corregida por grasa (25,89 kg) que las alimentadas con dietas a base de caña de azúcar (p<0,05). Conclusión: La caña de azúcar fresca o ensilada con aditivos se puede utilizar como fuente de forraje para vacas que producen hasta 23,43 kg d-1 leche corregida por grasa, siempre que la dieta total esté equilibrada adecuadamente.

Antecedentes: Há carência de estudos avaliando a adição de Lactobacillus plantarum e Pediococcus pentosaceus na silagem de cana-de-açúcar para vacas em lactação. Objetivo: Avaliar dietas contendo diferentes forragens e silagens com e sem inoculantes microbianos sobre o consumo, digestibilidade e produção de leite de vacas de média produção de leite. Métodos: Quinze vacas Holandesas foram distribuídas em um delineamento em blocos casualizados. Os tratamentos foram: 1) dieta com silagem de milho (CS), 2) dieta com cana-de-açúcar fresca (SC), 3) dieta com silagem de cana ensilada sem inoculantes (SS), 4) dieta com silagem de cana-de-açúcar ensilada com Lactobacillus buchneri (SSLB), ou 5) dieta com silagem de cana- de-açúcar ensilada com Lactobacillus plantarum, and Pediococcus pentosaceus (SSLP). Resultados: O consumo de matéria orgânica digestível foi menor (p<0,05) na dieta SSLB (9,77 kg day-1) comparada com CS (13,29 kg dia-1) e SSLP (12,42 kg dia-1). A ensilagem da cana-de-açúcar promoveu maior consumo de fibra em detergente neutro (FDN) em comparação com SC (média de 6,00 kg dia-1 versus 4.97 kg dia-1; p<0.05). A digestibilidade da matéria seca foi maior (p<0,05) para a dieta CS (77,80%) comparada com as dietas com silagem de cana-de-açúcar, enquanto que a digestibilidade da FDN foi menor para as dietas baseadas em cana-de-açúcar (p<0,05). A produção de leite foi similar entre CS (27,99 kg), SC (25,59 kg) e silagens com aditivos (25,47 e 27,07 para SSLB e SSLP, respectivamente). Vacas alimentadas com silagem de milho produziram mais leite corrigido para gordura (25,89 kg) que aquelas alimentadas com dietas baseadas em cana-de-açúcar (p<0,05). Conclusão: A cana-de-açúcar fresca ou ensilada com aditivos pode ser utilizada como fonte volumosa para vacas produzindo até 23,43 kg d-1 leite corrigido para gordura, desde que a dieta total esteja apropriadamente balanceada.