Science database

As a science-driven company, we regularly publish peer-reviewed papers to validate the research we conduct. 

Most recent publications

Hydroxychloride trace minerals improve apparent total tract nutrient digestibility in Bonsmara beef cattle

Ruminants
The effect of hydroxychloride trace minerals (HTM) on nutrient digestibility in comparison with sulphate trace minerals (STM) was tested in Bonsmara beef cattle fed Eragrostis tef hay as roughage, with high or low protein supplementation. Eight 12 month old Bonsmara beef heifers were housed individually and fed according to a duplicated 4 × 4 Latin square design. Two levels of protein supplementation, being 12.79% crude protein (CP) in the low protein concentrate and 30.16% CP in the high protein concentrate, were combined with two sources of trace minerals, being HTM and STM. All four diets contained 15 ppm added Cu, 50 ppm added Zn and 33 ppm added Mn. The Eragrostis tef hay roughage was fed ad libitum. The supplements including the minerals were fed separately daily at a fixed rate of 1.4 kg/heifer/day. Each period was 24 days starting with 18 days adaptation period followed by 6 days sampling period. The body weight and feed intake were measured during each period, to calculate growth performance. Feed and fecal samples were collected during sampling period and analyzed for nutrient digestibility, while acid insoluble ash was used as indigestible marker. On the last day of each period, rumen fluid was collected via a stomach tube for rumen pH and volatile fatty acid measurements.
by S. J. A. van Kuijk on 01/01/2022
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Performance and greenhouse gas emission of Nellore and F1 Angus × Nellore yearling bulls in tropical production systems during backgrounding and finishing

Ruminants
This study investigated the performance, carcass traits, and greenhouse gas emission of Nellore and F1 Angus × Nellore yearling bulls raised under two [lenient (S1) and intensified (S2)] production systems during the backgrounding and finishing phases. S1 was practiced on a 18.6 ha palisade grass pasture, divided into eight paddocks, which was not fertilized and managed using continuous stocking at a constant rate of two animals per hectare during backgrounding. Then, 20 Nellore [initial body weight (BWi), 277±13 kg; initial age, 15.2±1.1 months] and 20 F1 Angus × Nellore (BWi, 304±21 kg; initial age, 15.8±0.44 months) yearling bulls were randomly allocated to four paddocks for each breed. During finishing, animals remained on the pasture and received high supplementation (at rate of 2.0 kg•100 kg−1 BW). S2 was practiced on a 11.4 ha palisade grass pasture, divided into six paddocks, which was fertilized (150 kg N•ha−1•year−1) and managed using continuous stocking at variables rates during backgrounding. Then, 24 Nellore (BWi, 288±16 kg; initial age, 15.6±0.65 months) and 24 F1 Angus × Nellore (BWi, 325±18 kg; initial age, 15.8±0.42 months) yearling bulls were randomly allocated to three paddocks for each breed. During finishing, the bulls were moved to feedlots. During backgrounding, F1 Angus × Nellore bulls in S2 achieved the highest average daily gain (ADG) and final shrunk body weight (SBWf), whereas Nellore bulls in S1 achieved the lowest ADG and SBWf. During finishing, ADG and SBWf were greater in S2 than in S1 as well as for F1 Angus × Nellore bulls than for Nellore bulls. From the beginning of backgrounding until the end of finishing, the ribeye area of F1 Angus × Nellore bulls in S2 was larger than that of other bulls. The greatest backfat deposition occurred during finishing, resulting in greater backfat thickness of bulls in S2 than that of bulls in S1. The carbon footprint of F1 Angus × Nellore bulls in S2 (10.8 kg•CO2e•kg−1 carcass) was similar to that of Nellore bulls in S1, but it was approximately 13% and 11.5% lower than that of Nellore bulls in S2 and F1 Angus × Nellore bulls in S1, respectively. This study demonstrated that the enhancement of productivity through improving genetic merit and pasture management is a suitable strategy to reduce environmental impact and achieve environmental sustainability.
by Erick Escobar Dallantonia on 16/09/2021
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Intestinal adaptations to energy source of milk replacer in neonatal dairy calves

Ruminants
Most milk replacers (MR) contain more lactose compared with whole milk, which, when fed at a large meal size, could influence gut barrier function in calves. This study evaluated how replacing lactose in MR with fat (on a wt/wt basis) affects intestinal histomorphology and permeability in neonatal dairy calves. Thirty-four Holstein-Friesian bull calves were blocked by dam parity and randomly assigned to 1 of 2 treatments (n = 17): a high-lactose (46.1% lactose, 18.0% crude fat, and 23.9% crude protein of dry matter) or a high-fat MR (HF; 39.9% lactose, 24.6% crude fat, and 24.0% crude protein of dry matter). Calves were individually housed and fed pooled colostrum at 1.5 h and 12 h postnatally, at 18 and 9% of metabolic body weight (BW0.75), respectively. From 24 h postnatally until the end of the study (d 7), calves were transitioned to be fed MR (prepared at 15% solids) at 18% of BW0.75 twice daily at 0700 and 1900 h. During postprandial sampling on d 6, intestinal permeability was assessed by mixing lactulose (1.03 g/kg of BW0.75) and d-mannitol (0.31 g/kg of BW0.75) into the morning meal without altering total meal volume. Sequential blood samples were collected via jugular catheter, and total urine was collected for 12 h to measure the marker content. Calves were euthanized 3 h after the morning meal on d 7, and gastrointestinal tract tissues and digesta were collected for analysis of histomorphology, digesta osmolality, and gene expression. The empty gastrointestinal tracts of HF calves were heavier, although length did not differ and differences in histomorphology were minor. Digesta osmolality changed along the tract without differences between treatments. Plasma lactulose was greater in HF, although plasma d-mannitol and the recovery of both markers in urine were unaffected. No significant differences were detected in gene expression, although HF calves tended to have lower expression of TJP1 and CLDN2 and higher expression of proinflammatory cytokine IL1B in ileum tissue. In conclusion, partially replacing lactose in MR with fat resulted in a heavier and more permeable gut, with minor histomorphological differences.
by A. C. Welboren on 24/08/2021
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Animal nutrition strategies and options to reduce the use of antimicrobials in animal production

Across species
Antimicrobial resistance is a global and increasing threat. Stewardship campaigns have been established, and policies implemented, to safeguard the appropriate use of antimicrobials in humans, animals, and plants. Restrictions on their use in animal production are on the agenda worldwide. Producers are investing in measures, involving biosecurity, genetics, health care, farm management, animal welfare, and nutrition, to prevent diseases and minimize the use of antimicrobials. Functional animal nutrition to promote animal health is one of the tools available to decrease the need for antimicrobials in animal production. Nutrition affects the critical functions required for host defence and disease resistance. Animal nutrition strategies should therefore aim to support these host defence systems and reduce the risk of the presence in feed and water of potentially harmful substances, such as mycotoxins, anti-nutritional factors and pathogenic bacteria and other microbes. General dietary measures to promote gastrointestinal tract health include the selective use of a combination of feed additives and feed ingredients to stabilize the intestinal microbiota and support mucosal barrier function. This knowledge, used to establish best practices in animal nutrition, could allow the adoption of strategies to reduce the need for antimicrobials and contain antimicrobial resistance.
by C. Smits on 29/07/2021
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Dietary protein oscillation: Effects on feed intake, lactation performance, and milk nitrogen efficiency in lactating dairy cows

Ruminants
Limited research with growing ruminants indicates that oscillating (OS) dietary crude protein (CP) concentration may improve nitrogen use efficiency (NUE). Our aim was to determine if a total mixed ration (TMR) based on OS CP (48-h phases of 13.4% and 16.5% CP, respectively) would increase NUE of lactating dairy cows compared with a static CP TMR (ST; 14.9% CP). The experiment was a randomized complete block design with 50 cows [150 ± 61 (mean ± SD) d in milk]. Cows were blocked by parity, days in milk, and milk protein yield. On average, diets were equal in composition over the total experiment. Cows were milked twice daily, and 8 milk samples were collected in each 4-d period. Each 48 h of low-CP (LP) and high-CP (HP) TMR offered to OS cows corresponded to milk collected at milkings 1 to 4 and 5 to 8, respectively. Dry matter intake (mean = 25.5 kg/d for both treatment groups); yields of milk (mean = 31.5 kg/d for both treatment groups), protein, fat, lactose, and fat- and protein-corrected milk (mean = 33.6 kg/d for both treatment groups); and milk concentration of protein, fat, and lactose did not differ between treatments. However, milk urea concentration was higher for OS compared with ST (12.2 vs. 11.3 mg/dL). Body weight, body condition score, NUE, and feed efficiency were unaffected by OS. Apparent total-tract digestibility of dry matter (695 vs. 677 g/kg), organic matter (714 vs. 697 g/kg), CP (624 vs. 594 g/kg), neutral detergent fiber (530 vs. 499 g/kg), and starch (976 vs. 973 g/kg) were higher for OS than for ST cows. Cows in OS responded transiently, and regression analysis of differences within block over time revealed changes in yield of milk (−531 g/d), milk protein (−25.6 g/d), and milk lactose (−16.7 g/d) in LP. Opposite effects were observed for yield of milk (+612 g/d), milk protein (+28.8 g/d), and milk lactose (+28.0 g/d) during HP. Changes in concentrations of milk protein (−0.050%/d), lactose (+0.030%/d), and urea (−3.0 mg/dL per day) during LP, and in milk lactose (−0.024%/d) and urea (+4.3 mg/dL per day) during HP, were observed. Milk yield, lactose yield, and protein yield were lower for OS than ST cows at the last milking of LP and at the first milking of HP. Milk urea concentration did not show such a lag and was lower in the last 2 milkings of LP, and higher in the last 3 milkings of HP, in OS compared with ST cows. Overall, performance and NUE were unaffected by OS treatment, but apparent total-tract digestibility and milk urea concentration increased, and transient effects on milk yield and composition occurred in OS cows.
by R. Rauch on 08/07/2021
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Proteomic Analysis of Liver from Finishing Beef Cattle Supplemented with a Rumen-Protected B-Vitamin Blend and Hydroxy Trace Minerals

Ruminants
Vitamin B and trace minerals are crucial molecular signals involved in many biological pathways; however, their bioavailability is compromised in high-producing ruminant animals. So far, studies have mainly focused on the effects of these micronutrients on animal performance, but their use in a rumen-protected form and their impact on liver metabolism in finishing beef cattle is poorly known. We used a shotgun proteomic approach combined with biological network analyses to assess the effects of a rumen-protected B-vitamin blend, as well as those of hydroxy trace minerals, on the hepatic proteome. A total of 20 non-castrated Nellore males with 353 ± 43 kg of initial body weight were randomly assigned to one of the following treatments: CTRL—inorganic trace minerals without supplementation of a protected vitamin B blend, or SUP—supplementation of hydroxy trace minerals and a protected vitamin B blend. All animals were fed the same amount of the experimental diet for 106 days, and liver biopsies were performed at the end of the experimental period. Supplemented animals showed 37 up-regulated proteins (p < 0.10), and the enrichment analysis revealed that these proteins were involved in protein folding (p = 0.04), mitochondrial respiratory chain complex I (p = 0.01) and IV (p = 0.01), chaperonin-containing T-complex 2 (p = 0.01), glutathione metabolism (p < 0.01), and other aspects linked to oxidative-stress responses. These results indicate that rumen-protected vitamin B and hydroxy trace mineral supplementation during the finishing phase alters the abundance of proteins associated with the electron transport chain and other oxidation–reduction pathways, boosting the production of reactive oxygen species, which appear to modulate proteins linked to oxidative-damage responses to maintain cellular homeostasis.
28/06/2021
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ADSA Foundation Scholar Award: New frontiers in calf and heifer nutrition—From conception to puberty

Ruminants
Dairy calf nutrition is traditionally one of the most overlooked aspects of dairy management, despite its large effect on the efficiency and profitability of dairy operations. Unfortunately, among all animals on the dairy farm, calves suffer from the highest rates of morbidity and mortality. These challenges have catalyzed calf nutrition research over the past decade to mitigate high incidences of disease and death, and improve animal health, growth, welfare, and industry sustainability. However, major knowledge gaps remain in several crucial stages of development. The purpose of this review is to summarize the key concepts of nutritional physiology and programming from conception to puberty and their subsequent effects on development of the calf, and ultimately, future performance. During fetal development, developmental plasticity is highest. At this time, maternal energy and protein consumption can influence fetal development, likely playing a critical role in calf and heifer development and, importantly, future production. After birth, the calf's first meal of colostrum is crucial for the transfer of immunoglobulin to support calf health and survival. However, colostrum also contains numerous bioactive proteins, lipids, and carbohydrates that may play key roles in calf growth and health. Extending the delivery of these bioactive compounds to the calf through a gradual transition from colostrum to milk (i.e., extended colostrum or transition milk feeding) may confer benefits in the first days and weeks of life to prepare the calf for the preweaning period. Similarly, optimal nutrition during the preweaning period is vital. Preweaning calves are highly susceptible to health challenges, and improved calf growth and health can positively influence future milk production. Throughout the world, the majority of dairy calves rely on milk replacer to supply adequate nutrition. Recent research has started to re-evaluate traditional formulations of milk replacers, which can differ significantly in composition compared with whole milk. Transitioning from a milk-based diet to solid feed is critical in the development of mature ruminants. Delaying weaning age and providing long and gradual step-down protocols have become common to avoid production and health challenges. Yet, determining how to appropriately balance the amount of energy and protein supplied in both liquid and solid feeds based on preweaning milk allowances, and further acknowledging their interactions, shows great promise in improving growth and health during weaning. After weaning and during the onset of puberty, heifers are traditionally offered high-forage diets. However, recent work suggests that an early switch to a high-forage diet will depress intake and development during the time when solid feed efficiency is greatest. It has become increasingly clear that there are great opportunities to advance our knowledge of calf nutrition; yet, a more concentrated and rigorous approach to research that encompasses the long-term consequences of nutritional regimens at each stage of life is required to ensure the sustainability and efficiency of the global dairy industry. Key words
by J. K. van Niekerk on 26/05/2021
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Associations between feed efficiency and aspects of lactation curves in primiparous Holstein dairy cattle

Ruminants
Genetic selection for improved feed efficiency in dairy cattle has received renewed attention over the last decade to address the needs of a growing global population. As milk yield is a critical component of feed efficiency metrics in dairy animals, our objective was to evaluate the associations between feed efficiency in primiparous Holstein cattle and parameters of a mathematical model describing individual lactation curves. The Dijkstra lactation curve model was fit to individual lactation records from 34 Holstein heifers with previously estimated measures of feed efficiency. We found that the optimal fit of the Dijkstra model was achieved using daily milk yield records up to 21 d in milk to capture the rise to peak milk yield and using monthly dairy herd improvement records for the remainder of lactation to accurately characterize lactation persistency. In the period of lactation before peak milk yield, improved feed efficiency was associated with a faster increase in daily milk yield over a shorter period of time at the expense of increased mobilization of body reserves; this serves to reinforce the concept that dairy cattle are primarily capital breeders versus income breeders. Feed efficiency in the period following peak lactation, as measured by gross feed efficiency, return over feed costs, and net energy efficiency of lactation, was positively associated with higher peak milk yield. The findings in early lactation suggest that estimates of feed efficiency could be improved by evaluating feed efficiency relative to conception, rather than parturition and lactation, to better account for the energy stored and released from body reserves in capital breeding.
by D. J. Seymour on 28/04/2021
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Preweaning nutrient supply alters serum metabolomics profiles related to protein and energy metabolism and hepatic function in Holstein heifer calves

Ruminants
Lifting the preweaning milk restriction in dairy calves has been causally associated with beneficial effects on growth and future lactation performance. However, the biological mechanisms linking early-life nutrient supply and future performance remain insufficiently understood. Thus, the objective of this study was to characterize growth and the metabolic profiles of calves fed a restricted (RES) and an elevated (ELE) milk supply preweaning. A total of 86 female Holstein Friesian calves were blocked in pairs by maternal parity and received identical colostrum supply within block. Treatments randomized within block consisted of a milk replacer (MR; 24% crude protein, 18% crude fat, and 45% lactose) supplied at either 5.41 Mcal of ME in 8 L of MR/d (ELE) or 2.71 Mcal of ME in 4 L of MR/d (RES) from d 2 after birth until they were stepped down by 50% during wk 7 and fully weaned at wk 8. All calves had ad libitum access to pelleted calf starter (17.3% crude protein, 24.4% neutral detergent fiber, 2.0% crude fat, and 18.2% starch), chopped wheat straw, and water. At 2 and 49 d of age, blood samples were taken for metabolomics analysis. The ELE group by design consumed more milk replacer, resulting in a lower starter intake and a greater body weight and average daily gain. The ELE calves consumed 20.7% more ME and 9.7% more crude protein. However, efficiency of growth was not different between groups. Metabolomic profiling using 908 identified metabolites served to characterize treatment-dependent biochemical differences. Principal component analysis revealed clearly distinct metabolic profiles at 49 d of age in response to preweaning milk supply. Changes in energy (fatty acid metabolism and tricarboxylic acid metabolites), protein (free AA, dipeptides, and urea cycle), and liver metabolism (bile acid and heme metabolism) were the main effects associated with the dietary differences. The ELE group consumed proportionately more glucogenic nutrients via milk replacer, whereas the RES group consumed proportionately more ketogenic nutrients from the digestion of the calf starter, comprising a larger portion of total intake. Associated with the higher growth rate of the ELE group, hepatic changes were expressed as differences in bile acid and heme metabolism. Furthermore, energy metabolism differences were noted in fatty acid and AA metabolism and the urea cycle. The metabolic profile differences between the ELE and RES groups reflect the broad differences in nutrient intake and diet composition and might point to which metabolic processes are responsible for greater dairy performance for cows fed a greater milk supply preweaning.
by L. N. Leal on 21/04/2021
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