Consumer knowledge and perceptions of milk fat in Denmark, the United Kingdom, and the United States.

This study examined the relationship between consumers' country of origin: Denmark (DK), the United Kingdom (UK), and the United States (US) and their knowledge and perceptions of milk fat. Adult participants answered a web-based survey, and data were collected online from December 2018 to April 2019, in DK, the UK, and the US. A total of 694 participants completed the online survey. Most respondents were between 18 and 39 years old, female, highly educated, and employed. Most UK respondents consumed milk daily (73%), whereas in DK (56%) and the US (46%) consumption was significantly lower. Whole milk and semi-skim milk were consumed less by respondents in DK (20 and 36%, respectively) compared with the UK (50 and 49%, respectively) and the US (47 and 50%, respectively). Danish respondents (53%) consumed more skim milk than respondents from the UK (16%) and the US (19%). Concern about milk fat was higher in DK (60%) than in the UK (34%) and the US (31%). More respondents considered milk fat to be "healthy" or "very healthy" in the UK (31 and 10%, respectively) and the US (37 and 19%, respectively), than in DK (23 and 6%, respectively). Nutritional benefit was the most important reason for perceiving milk fat as healthy in the 3 countries. Awareness of milk saturated fat was higher among respondents from the UK (53%) than from DK (44%) and the US (38%). Results suggest that consumers in DK are different in their perceptions of milk fat, but consumers in the UK and the US share common characteristics.

Influence of green grass-based diets on growth and reproductive performance in dairy heifers.

The objective of this study was to monitor the changes in growth, dry matter intake, and blood profiles (nutrition and reproductive hormones) of dairy heifers in response to green grass-based diets. Twelve crossbred heifers were equally divided into group 1: rice straw and concentrate; group 2: rice straw, green grass, and concentrate; group 3: green grass and concentrate; group 4: green grass, soybean hay, and concentrate. Dry matter intake in group 4 was found 6% higher (P < 0.05) than group 1. Negative body weight gain was found in group 1 and group 2 showed 14% higher body weight gain per 30 days compared to groups 3 and 4 (P < 0.05). Heifers in group 4 had significantly (P < 0.05) higher heart girth gain, serum albumin, urea, and blood urea nitrogen than the heifers in other groups. Endocrine parameters were found similar among groups. Overall, supply of green grass especially a mix of leguminous and non-leguminous was found advantageous in heifer feeding.

Transport of fatty acids within plasma lipoproteins in lactating and non-lactating cows fed on fish oil and hydrogenated palm oil.

The aim of this study was to elucidate the effect of dietary fish oil (FO) and a blend of FO and hydrogenated palm oil (FOPO) on transport of fatty acids (FA) within plasma lipoproteins in lactating and non-lactating cows. Two trials were conducted (one with lactating and another with non-lactating dairy cows) in two 3 × 3 Latin squares that included three periods of 21 days. Dietary treatments for lactating cows consisted of a basal diet (Control; no fat supplement), and fat-supplemented diets containing FO (500 g/day/cow) and FOPO (250 FO + 250 g/day/cow hydrogenated palm oil). For non-lactating cows, dietary treatments consisted of a basal diet (Control; no fat supplement), and fat-supplemented diets containing FO (170 g/day/cow) and FOPO (85 FO + 85 hydrogenated palm oil g/day/cow). In lactating cows, compared with control and FOPO, FO increased C16:0, C18:3 cis-9, 12, 15, C18:2 cis-9, trans-11 and total saturated and polyunsaturated FA in plasma and increased C16:0, C18:2 cis-9, trans-11, total polyunsaturated and total polyunsaturated n-6 in high-density lipoprotein (HDL), whereas in non-lactating cows, compared with control and FOPO, FO increased C16:0, C18:1 trans-11, C18:2 trans-9, 12, C18:2 cis-9, trans-11, C20:5 n-3 and total saturated and polyunsaturated FA in plasma; C16:0, C18:1 trans-11, C18:1 cis-9, C18:2 trans-9, 12, C20:5 n-3 and total monounsaturated FA in HDL; and C18:1 trans-6-8, C18:1 trans-9, C18:1 trans-10, C18:1 trans-11, C18:3 cis-9, 12, 15 and C20:5 n-3 in low-density lipoprotein (LDL). FO increased C20:5 n-3 in plasma and lipoproteins in non-lactating cows and increased C18:3 cis-9, 12, 15 in plasma (in lactating cows) and LDL (in non-lactating cows). We concluded from results of this study that in bovine plasma, the LDL fraction appears to be the main lipoprotein transporting C18:1 trans isomers and is more responsive than other lipoprotein fractions to variation in supply of dietary lipids.

Short communication: Chemical composition, fatty acid composition, and sensory characteristics of Chanco cheese from dairy cows supplemented with soybean and hydrogenated vegetable oils.

Lipid supplements can be used to alter fatty acid (FA) profiles of dairy products. For Chanco cheese, however, little information is available concerning effects of lipid supplements on sensorial properties. The objective of this study was to examine effects of supplementation of dairy cow diets with soybean (SO) and hydrogenated vegetable (HVO) oils on chemical and FA composition of milk and cheese and sensory characteristics of cheese. Nine multiparous Holstein cows averaging 169±24d in milk at the beginning of the study were used in a replicated (n=3) 3×3 Latin square design that included 3 periods of 21d. All cows received a basal diet formulated with a 56:44 forage:concentrate ratio. Dietary treatments consisted of the basal diet (control; no fat supplement), and the basal diet supplemented with SO (unrefined oil; 500g/d per cow) and HVO (manufactured from palm oil; 500g/d per cow). Milk fat yield was lower with HVO compared with control and SO. Cheese chemical composition and sensory profile were not affected by dietary treatment. Vaccenic (C18:1 trans-11) and oleic (C18:1 cis-9) acids were higher for SO than for control and HVO. Compared with control and HVO, SO decreased saturated FA and increased monounsaturated FA. The thrombogenic index of milk and cheese produced when cows were fed SO was lower than when cows were fed on control and HVO. The outcome of this study showed that, compared with control and HVO, supplementing dairy cow diets with SO improves milk and cheese FA profile without detrimental effects on the chemical composition of milk and cheese and the sensory characteristics of cheese.

Estimation of milk yield based on udder measures of Pelibuey sheep using artificial neural networks.

Udder measures have been used to assess milk yield of sheep through classical methods of estimation. Artificial neural networks (ANN) can deal with complex non-linear relationships between input and output variables. In the current study, ANN were applied to udder measures from Pelibuey ewes to estimate their milk yield and this was compared with linear regression. A total of 357 milk yield records with its corresponding udder measures were used. A supervised learning was used to train and teach the network using a two-layer ANN with seven hidden structures. The globally convergent algorithm based on the resilient backpropagation was used to calculate ANN. Goodness of fit was evaluated using the mean square prediction error (MSPE), root MSPE (RMSPE), correlation coefficient (r), Bayesian's Information Criterion (BIC), Akaike's Information Criterion (AIC) and accuracy. The 15-15 ANN architecture showed that the best predictive milk yield performance achieved an accuracy of 97.9% and the highest values of r2 (0.93), and the lowest values of MSPE (0.0023), RMSPE (0.04), AIC (- 2088.81) and BIC (- 2069.56). The study revealed that ANN is a powerful tool to estimate milk yield when udder measures are used as input variables and showed better goodness of fit in comparison with classical regression methods.

Effects of copper nanoparticles on performance, muscle and bone characteristics and serum metabolites in broilers.

Three hundred and twenty day old Hubbard broilers were randomly allocated to four treatments (8 replicates, 10 birds/pen) and were raised under standard management conditions. Birds in the first group served as control and were fed a corn based diet, while birds in the remaining three groups i.e.; A, B and C were fed with a basal diet supplemented with copper nanoparticles (CuNP) at 5, 10 and 15 mg /kg of diet respectively for 35 days. Supplementation of CuNP linearly increased (P≤0.05) body weight (BW), average daily weight gain (ADWG) and feed intake (FI) in broilers. Uric acid, glucose levels in blood and feed conversion ratio (FCR) reduced linearly (P≤0.05) with CuNP supplementation in diet. Supplementation of CuNP in the diet also linearly increased (P≤0.05) tibia weight, length, diameter, weight/length index (W/L) and Tibiotarsal index (TT index). Inclusion of CuNP in broilers diet linearly increased the measured parameters of muscle i.e.; pH, fiber diameter, fiber cross-sectional area, fascicle diameter, fascicle cross-sectional area (P≤0.05). Concentration of copper, iron, calcium and phosphorous in blood also increased line-arly (P ≤ 0.05) with CuNP supplementation. Overall, CuNP positively affected the growth performance, histological characteristics of muscles, bone strength and serum metabolites in broilers.

Effect of tannins from tropical plants on methane production from ruminants: A systematic review.

Methane (CH4) is a greenhouse gas generated during the feed fermentation processes in the rumen. However, numerous studies have been conducted to determine the capacity of plant secondary metabolites to enhance ruminal fermentation and decrease CH4 production, especially those plants rich in tannins. This review conducted a descriptive analysis and meta-analysis of the use of tannin-rich plants in tropical regions to mitigate CH4 production from livestock. The aim of this study was to analyse the effect of tannins supplementation in tropical plants on CH4 production in ruminants using a meta-analytic approach and the effect on microbial population. Sources of heterogeneity were explored using a meta-regression analysis. Final database was integrated by a total of 14 trials. The 'meta' package in R statistical software was used to conduct the meta-analyses. The covariates defined a priori in the current meta-regression were inclusion level, species (sheep, beef cattle, dairy cattle, and cross-bred heifers) and plant. Results showed that supplementation with tropical plants with tannin contents have the greatest effects on CH4 mitigation . A negative relationship was observed between the level of inclusion and CH4 emission (-0.09), which means that the effect of CH4 mitigation is increasing as the level of tannin inclusion is higher. Therefore, less CH4 production will be obtained when supplementing tropical plants in the diet with a high dose of tannins.

Effects of feeding forage soybean silage on milk production, nutrient digestion, and ruminal fermentation of lactating dairy cows.

The objective of this study was to determine the feeding value of forage soybean silage (SS) for dairy cows relative to a fourth-cut alfalfa silage (AS). Forage soybean was harvested at full pod stage. Two isonitrogenous diets were formulated with a 48:52 forage:concentrate ratio. Soybean silage and AS constituted 72% of the forage in each diet, with corn silage constituting the remaining 28%. Twenty Holsteins cows in early lactation were used in a switchback design. Four lactating Holsteins cows fitted with ruminal cannulas were used to determine the effects of dietary treatments on ruminal fermentation parameters and in vivo total tract nutrient utilization. Relative to AS, SS contained 15, 28, and 25% more neutral detergent fiber, acid detergent fiber, and crude protein, respectively. Dry matter intake (23.5 vs. 25.1 kg/d) and milk yield (35.5 vs. 37.2 kg/d) were lower for cows fed SS than for those fed AS. However, energy-corrected milk and milk efficiency were similar for both dietary treatments. Milk protein, lactose, and total solids concentrations were not influenced by dietary treatments (average 3.0, 4.7, and 12.6%, respectively). However, cows fed SS produced milk with greater milk fat (3.8 vs. 3.6%) and milk urea nitrogen concentrations (15.6 vs. 14.3 mg/dL) compared with cows fed AS. Ruminal pH was lower, whereas ruminal NH3-N concentration was greater in cows fed SS than in cows fed AS. Total tract digestibilities of dry matter, crude protein, and neutral detergent fiber were not influenced by silage type. We concluded that forage SS, when compared with AS, had a negative impact on feed intake and milk yield, whereas energy-corrected milk, milk efficiency, and total tract nutrient digestion were similar.

Technical note: use of internal transcribed spacer for ruminal yeast identification in dairy cows.

Molecular techniques are important tools for microbiological studies in different habitats, and the internal transcribed spacer (ITS) has been proved to be useful for analyzing fungal diversity. The aim of this study was to use the ITS region to generate ruminal yeast profile and to identify ruminal yeast. DNA from ruminal digesta was extracted to amplify the ribosomal ITS region. The profile from the PCR products was visualized and the excised bands from the profile were identified as the genera Millerozyma, Pichia, Rhizomucor and Hyphopichia. Overall, the ITS resulted to be a simple, fast and sensitive approach that allowed profiling and identification of ruminal yeast that have not been previously described (Millerozyma and Hyphopichia) in the rumen microbial community.

Quantitative analysis of ruminal bacterial populations involved in lipid metabolism in dairy cows fed different vegetable oils.

Vegetable oils are used to increase energy density of dairy cow diets, although they can provoke changes in rumen bacteria populations and have repercussions on the biohydrogenation process. The aim of this study was to evaluate the effect of two sources of dietary lipids: soybean oil (SO, an unsaturated source) and hydrogenated palm oil (HPO, a saturated source) on bacterial populations and the fatty acid profile of ruminal digesta. Three non-lactating Holstein cows fitted with ruminal cannulae were used in a 3×3 Latin square design with three periods consisting of 21 days. Dietary treatments consisted of a basal diet (Control, no fat supplement) and the basal diet supplemented with SO (2.7% of dry matter (DM)) or HPO (2.7% of DM). Ruminal digesta pH, NH3-N and volatile fatty acids were not affected by dietary treatments. Compared with control and HPO, total bacteria measured as copies of 16S ribosomal DNA/ml by quantitative PCR was decreased (P<0.05) by SO. Fibrobacter succinogenes, Butyrivibrio proteoclasticus and Anaerovibrio lipolytica loads were not affected by dietary treatments. In contrast, compared with control, load of Prevotella bryantii was increased (P<0.05) with HPO diet. Compared with control and SO, HPO decreased (P<0.05) C18:2 cis n-6 in ruminal digesta. Contents of C15:0 iso, C18:11 trans-11 and C18:2 cis-9, trans-11 were increased (P<0.05) in ruminal digesta by SO compared with control and HPO. In conclusion, supplementation of SO or HPO do not affect ruminal fermentation parameters, whereas HPO can increase load of ruminal P. bryantii. Also, results observed in our targeted bacteria may have depended on the saturation degree of dietary oils.