Effects of exchanging lactose for fat in milk replacer on ad libitum feed intake and growth performance in dairy calves

The recent trend in the dairy industry toward ad libitum feeding of young calves merits reconsideration of calf milk replacer (CMR) formulations. Additionally, feed intake regulation in young calves provided with ad libitum milk and solid feeds is insufficiently understood. This study was designed to determine the effect of exchanging lactose for fat in CMR on voluntary feed intake and growth performance. Lactose was exchanged for fat on a weight/weight basis, resulting in different energy contents per kilogram of CMR. Thirty-two male calves (1.7 ± 0.12 d of age, 47.6 ± 0.83 kg of body weight) were assigned to 1 of 16 blocks based on arrival date. Within each block, calves were randomly assigned to 1 of 2 treatments. The experimental period was divided into 4 periods. In period 1, until 14 ± 1.7 d of age, calves were individually housed, restricted-fed their assigned CMR treatments at 2.5 to 3 L twice daily, and provided with unlimited access to water, chopped straw, and starter. In period 2, calves were group-housed with 8 calves per pen and received ad libitum access to their assigned CMR treatments, starter feed, chopped wheat straw, and water. During period 3, from 43 until 63 d of age, calves were weaned by restricting CMR allowance in 2 steps, maintaining access to all other feeds. All calves were completely weaned at d 64 of age and were monitored until 77 d of age (period 4). Measurements included the intake of all dietary components, body weight gain, and a selection of blood traits. Increasing fat content at the expense of lactose decreased CMR intake by 10%, whereas total calculated metabolizable energy intake and growth remained equal between treatments. Total solid feed (starter and straw) consumption was not affected by CMR composition. These data indicate that calves fed ad libitum regulate their CMR intake based on energy content. High-fat CMR increased plasma phosphate, nonesterified fatty acids, triglycerides, and bilirubin, whereas plasma glucose remained unchanged. Despite the limited animal numbers in the present experiment, there was a significant decrease in the total number of health events (mainly respiratory) requiring therapeutic intervention and in the total number of therapeutic interventions in calves fed high-fat CMR. Calves appeared to consume CMR based on energy content, with a difference in ad libitum intake proportional to the difference in energy content of the CMR, maintaining equal body weight gain and solid feed intake.</p

Supplementation of lamb diets with vitamin E and rosemary extracts on meat quality parameters

BACKGROUND Supranutritional supplementation of lamb diets with alpha-tocopherol is an effective method to reduce lipid oxidation and colour deterioration in meat products. However, alternative antioxidant sources have been proposed to replace the supranutritional vitamin E applications. RESULTS Indoor concentrate-fed Rasa Aragonesa male lambs (n = 480) were supplemented with increasing levels of all-rac-alpha-tocopheryl acetate (0.25, 0.5, 1.0 g kg(-1) compound feed), rosemary extract (0.20, 0.40, or 0.80 g kg(-1) compound feed), or rosemary extract embedded in a fat matrix (0.20, 0.40, or 0.80 g kg(-1) compound feed) for 14 days before slaughter. The longissimus thoracis et lumborum muscle from three lambs per pen (18 lambs per treatment) were modified-atmosphere packaged (70% O-2 + 30% CO2) and maintained under retail conditions for 14 days. Supranutritional supplementation with antioxidants had no effect (P > 0.05) on average daily weight gain, feed intake, and feed efficiency. Rosemary extract supplementation (with or without fat embedment) had no effect on lipid oxidation, myoglobin forms, or colour stability parameters, regardless of the dose. All vitamin E supplementation levels significantly affected lipid oxidation, colour stability (L*, C*, and h), myoglobin forms, and meat discoloration parameters compared with non-supplemented lambs. CONCLUSIONS This study demonstrates that, unlike vitamin E, neither dose nor protection of the rosemary extract had an effect on lipid oxidation or meat colour stability of lambs during the 14 days of storage under retail conditions

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Effects of mixing a high-fat extruded pellet with a dairy calf starter on performance, feed intake, and digestibility

During weaning, withdrawal of milk replacer is not directly compensated for by an increase in solid feed intake. Therefore, greater fat inclusion in the starter might mitigate this temporary dietary energy decline. However, fat inclusion in solid feeds may generally limit rumen fermentability and development. To address these potentially conflicting outcomes, we conducted 2 experiments to evaluate the effect of supplementing a high-fat extruded pellet mixed with a calf starter on feed intake, performance, and nutrient digestibility in calves. In experiment 1, 60 Holstein bull calves were blocked by serum IgG (2,449 ± 176 mg/dL) and date of arrival (2.5 ± 0.5 d of age). Within each block, calves were randomly assigned to 1 of 3 treatments: a standard control calf starter (CON; 3.1% fat) and mixtures of CON with 10% inclusion of 1 of 2 different high-fat extruded pellets containing 85% of either hydrogenated free palm fatty acids (PFA, 7.1% fat) or hydrogenated rapeseed triglycerides (RFT, 6.7% fat). Calves were offered milk replacer up to 920 g/d until 42 d of age, followed by a gradual weaning period of 7 d. Calves had ad libitum access to the starter diets, straw, and water. No differences were observed between CON, PFA, and RFT calves on body weight (BW) or average daily gain (ADG) until 49 d of age. From weaning (50 d) until 112 d, PFA calves had a greater BW and ADG than RFT and CON animals. Moreover, PFA calves had the highest intakes of starter, straw, calculated metabolizable energy, and crude protein after weaning. Overall, no differences were present in blood β-hydroxybutyrate and glucose concentrations between treatments; however, calves in the RFT treatment had a higher concentration of insulin-like growth factor-1. In experiment 2, 24 Holstein bull calves at 3 mo of age were assigned to 1 of 8 blocks based on arrival BW and age. Within each block, calves were randomly assigned to 1 of the 3 treatments previously described for experiment 1. Calves on the RFT treatment had the lowest total-tract apparent dry matter and fat digestibility, potentially explaining the differences in performance observed between PFA and RFT calves. Inclusion of the PFA pellet at 10% with a calf starter improved BW, solid feed, and energy intake after weaning. However, these benefits were conditioned by fat source and its digestibility

Effect of energy source in calf milk replacer on performance, digestibility, and gut permeability in rearing calves

Current calf milk replacer (CMR) compositions significantly differ from whole milk in their levels of energy, protein, and minerals. Energy source is one of the major differences, as CMR contains high levels of lactose, whereas whole milk contains higher levels of fat. The aim of this study was to determine the effect of partially exchanging lactose for fat on performance, digestibility, and gut permeability in calves fed twice daily on a high feeding plane. Lactose and fat were exchanged in the CMR formulation on a weight–weight basis. The CMR were isonitrogenous but not isoenergetic. A total of 60 male Holstein-Friesian calves were assigned to 1 of 30 blocks based on serum IgG, body weight, and date of collection after birth. Within each block, calves were randomly assigned to 1 of 2 treatments: high fat and high lactose. The CMR was provided twice daily until 49 d of age, followed by a gradual weaning period of 14 d. Starter, straw, and water were available ad libitum throughout the complete study. Exchanging lactose for fat did not affect growth; intakes of starter, straw, water, crude protein, or total energy; or apparent total-tract digestibility of nutrients. Gastrointestinal permeability was assessed by measuring the recovery of lactulose and Cr in 24-h urine and the Cr concentration and lactulose:D-mannitol ratio in serum following an oral pulse dose. Urinary recoveries of Cr and lactulose were generally low in both treatments but were higher in calves fed the high-fat CMR. Accordingly, the serum lactulose:D-mannitol ratio and serum Cr concentrations were higher in calves fed the high-fat CMR. In wk 1 and during the weaning transition, calves fed the high-fat CMR had significantly fewer abnormal fecal scores. In conclusion, exchanging lactose for fat in the CMR did not affect growth performance, total feed intake, or nutrient digestibility. The high-fat CMR was associated with an increase in permeability markers but positively influenced fecal scores in calves.</p

Preweaning nutrient supply alters mammary gland transcriptome expression relating to morphology, lipid accumulation, DNA synthesis, and RNA expression in Holstein heifer calves

The objective of this study was to analyze the mammary gland transcriptome to determine how preweaning nutrient supply alters the molecular mechanisms that regulate preweaning mammary development. Holstein heifers were fed via milk replacer (MR) either an elevated level of nutrient intake (ELE; on average, 5.9 ± 0.2 Mcal of ME in 8.4 L of MR/d, n = 6) or a restricted amount of nutrients (RES; 2.8 ± 0.2 Mcal of ME in 4 L of MR/d, n = 5) for 54 d after birth, at which point they were slaughtered and samples of mammary parenchyma tissue were obtained. Parenchymal mRNA was analyzed, and the fold change (FC) of 18,111 genes (ELE relative to RES) was uploaded to Ingenuity Pathway Analysis (IPA) software (Qiagen Bioinformatics, Redwood City, CA) for transcriptomic analysis. Using a threshold of P 2) and 7 were inhibited (Z < −2). In summary, feeding ELE preweaning altered the mammary transcriptome of Holstein heifers, affecting cell functions involved in the morphological and physiological development of the mammary gland.</p