To produce milk that is healthier for human consumption, the present study evaluated the effect of including canola oil in the diet of dairy cows on milk production and composition as well as the nutritional quality of this milk fat. Eighteen Holstein cows with an average daily milk yield of 22 (± 4) kg/d in the middle stage of lactation were used. The cows were distributed in 6 contemporary 3x3 Latin squares consisting of 3 periods and 3 treatments: control diet (without oil), 3% inclusion of canola oil in the diet and 6% inclusion of canola oil in the diet (dry matter basis). The inclusion of 6% canola oil in the diet of lactating cows linearly reduced the milk yield by 2.51 kg/d, short-chain fatty acids (FA) by 41.42%, medium chain FA by 27.32%, saturated FA by 20.24%, saturated/unsaturated FA ratio by 39.20%, omega-6/omega-3 ratio by 39.45%, and atherogenicity index by 48.36% compared with the control treatment. Moreover, with the 6% inclusion of canola oil in the diet of cows, there was an increase in the concentration of long chain FA by 45.91%, unsaturated FA by 34.08%, monounsaturated FA by 40.37%, polyunsaturated FA by 17.88%, milk concentration of omega-3 by 115%, rumenic acid (CLA) by 16.50%, oleic acid by 44.87% and h/H milk index by 94.44% compared with the control treatment. Thus, the inclusion of canola oil in the diet of lactating dairy cows makes the milk fatty acid profile nutritionally healthier for the human diet; however, the lactating performance of dairy cows is reduce.

Fluid milk and its derivatives are important dietary ingredients that contribute to daily nutrient intake of the modern Homo sapiens. To produce milk that is healthier for human consumption, the present study evaluated the effect of adding soybean oil and linseed oil in the diet of lactating cows. The fatty acid profile of milk, milk composition, and the blood parameters of cows were evaluated. Eighteen Holstein cows were distributed in a replicated Latin square design and distributed according to the following treatments: 1) Control (CC): traditional dairy cow diet, without addition of oil; 2) Soybean oil (SO): 2.5% addition of soybean oil to the traditional diet, as a source of omega-6; 3) Linseed oil (LO): 2.5% addition of linseed oil in the diet as a source of omega-3. Milk production was not affected, but oil supplementation decreased feed intake by 1.93 kg/cow/day. The milk fat percentage was significantly lower when cows were supplemented with vegetable oil (3.37, 2.75 and 2.89% for CC, SO and LO, respectively). However, both soybean and linseed oils decreased the concentration of saturated fatty acids (66.89, 56.52 and 56.60 g/100g for CC, SO and LO respectively), increased the amount of unsaturated fatty acids in milk (33.05, 43.39, and 43.35 g/100g for CC, SO and LO respectively) and decreased the ratio between saturated/unsaturated fatty acids (2.12, 1.34, and 1.36 for CC, SO and LO respectively). Furthermore, SO and LO increased significantly the concentration of monounsaturated fatty acids (29.58, 39.55 and 39.47 g/100g for CC, SO and LO respectively), though it did not significantly alter the level of polyunsaturated fatty acids in milk fat (3.57, 3.93 and 3.98 g/100g for CC, SO and LO respectively). Supplementation with LO enhanced the concentration of omega-3 fatty acids on milk (0.32, 0.36, and 1.02 for CC, SO and LO respectively). Blood variables aspartate aminotransferase, gamma glutamyl transferase, urea, albumin, creatinine and total proteins were not altered. On the other hand, total cholesterol, HDL and LDL were greater in the group supplemented with vegetable oils. Supplementation with vegetable oils reduced the dry matter intake of cows, the fat content of milk, and improved saturated/unsaturated fatty acid ratio of milk fat. Compared to the SO treatment, animals fed LO produced milk with greater content of omega-3, and a more desirable omega-6/omega-3 ratio on a human nutrition perspective. Thus, the inclusion of SO and LO in the diet of lactating dairy cows makes the milk fatty acid profile nutritionally healthier for the human consumption.

Resumo -O objetivo deste trabalho foi avaliar o desempenho de bezerros Nelore recém-desmamados em resposta à suplementação com aditivos nutricionais e minerais orgânicos no sal mineral proteinado, em pastagem de Urochloa brizantha 'Marandu', na época seca. Foram utilizados 112 bezerros com idade entre 7-8 meses e com 252±24 kg. Os animais foram divididos em pastos sob lotação rotativa e receberam os tratamentos: sal mineral proteinado (controle); e sal mineral proteinado com minerais na forma orgânica, com monensina ou com óleos funcionais. A cada ciclo de pastejo, foram calculados o consumo de suplemento, o ganho de peso e a eficiência; coletadas amostras de sangue para análise de minerais; e feitas ultrassonografias de carcaça. O consumo do tratamento com monensina foi inferior ao dos demais (0,47 kg por dia); os consumos dos tratamentos controle (0,82 kg por dia) e com óleo (0,8 kg por dia) foram semelhantes; e o do tratamento com minerais orgânicos foi superior ao dos outros (0,92 kg por dia). Diferenças entre os tratamentos não foram observadas para ganho de peso (0,123 kg por dia) e para eficiência (0,161). A área de olho de lombo (46,81 cm 2 ) e a espessura de gordura subcutânea (0,77 mm) não diferiram significativamente entre os tratamentos. A adição de monensina diminui o consumo do suplemento, o que pode significar menor ingestão de proteína e prejuízo ao desempenho dos animais.Termos para indexação: Bos taurus, consumo, ganho de peso, monensina, óleos funcionais, ultrassonografia de carcaça. Supplementation with nutritional additives and organic minerals on the performance of newly-weaned Nellore calves on pastureAbstract -The objective of this work was to evaluate the performance of newly-weaned Nellore calves in response to supplementation with additives and organic minerals in protein mineral salt, in Urochloa brizantha 'Marandu' pasture, in the dry season. One hundred and twelve calves aged between 7-8 months and with 252±24 kg were used. The animals were divided into pastures under rotational stocking and received the following treatments: protein mineral salt (control); and protein mineral salt with minerals in organic form, with monensin, or with functional oils. For each grazing cycle, supplement intake, weight gain, and efficiency were calculated; blood samples for analysis of minerals were collected; and carcass ultrasound was made. The intake of the treatment with monensin was lower than that of the other ones (0.47 kg per day); the intakes of the control (0.82 kg per day) and the oil (0.8 kg per day) treatments were similar; and the intake of the treatment with organic minerals was higher than that of the others (0.92 kg per day). Differences among treatments were not observed for weight gain (0.123 kg per day) and for efficiency (0.161). Ribeye area (46.81 cm 2 ) and fat thickness (0.77 mm) did not differ significantly among treatments. The addition of monensin decreases supplement intake, which can mean lower protein ingestion and limited animal performance.

The objective was to evaluate the effects of a specific strain of live yeast (LY) on growth performance, fermentation parameters, feed efficiency and bacterial communities in the rumen of growing cattle fed low-quality hay. In experiment (Exp) 1, twelve Droughtmaster bull calves (270 kg ± 7.6 kg initial BW) were blocked by BW into two groups, allocated individually in pens, and fed ad libitum Rhodes grass hay (8.4% of crude protein [CP]), and 300 g/bull of supplement (52% CP) without (Control) or with LY (8 x 10 9 CFU/day Saccharomyces cerevisiae CNCM I-1077, Lallemand Inc., Montreal, Canada) for 28 d, followed by seven days in metabolism crates. Blood and rumen fluid were collected before feeding and 4 h after feeding. In Exp 2, for assessment of growth performance, 48 Charbray steers (329 kg ± 20.2 kg initial BW) were separated into two blocks by initial BW and randomly allocated into 12 pens. The steers were fed Rhodes grass hay (7.3% CP) and 220 g/steer of supplement (60% CP) without or with LY (8 x 10 9 CFU/day) for 42 d, after a two-week adaptation period. In Exp 1, fiber digestibility was calculated from total fecal collection and in Exp 2, indigestible NDF was used as marker. Inclusion of LY increased (P = 0.03) NDF intake by 8.3% in Exp 1, without affecting total tract digestibility. No changes were observed in microbial yield or in the efficiency of microbial production. There was a Treatment × Time interaction (P < 0.01) for the molar proportion of short chain fatty acids, with LY increasing propionate before feeding. Inclusion of LY decreased rumen ammonia 4 h after feeding (P = 0.03). Addition of LY reduced rumen bacterial diversity and the intraday variation in bacterial populations. Relative populations of Firmicutes and Verrucomicrobia varied over time (P < 0.05) only within the Control group. At the genus level, the relative abundance of an unclassified bacterial genus within the order Clostridiales, a group of cellulolytic bacteria, was reduced from 0 to 4 h after feeding in the Control group (P = 0.02) but not in the LY group (P = 1.00). During Exp 2, LY tended to increase ADG (P = 0.08) and feed efficiency (P = 0.10), with no effect on NDF intake or digestibility. In conclusion, S. cerevisiae CNCM I-1077 reduced the intraday variation of rumen bacteria and increased the amount of NDF digested per day. These observations could be associated with the tendency of increased ADG and feed efficiency in growing cattle fed a low-quality forage.

Animal temperament evaluation can be included in the cattle selection program also because of an existing correlation with performance. However, there are different assessment methods such as flight speed (time and speed that an animal takes to leave the crush) and exit score (indicating in which pace it does). Flight zone (FZ) refers to the distance that an animal allows human proximity without signs of fear (e.g., moving away and/or aggression) and it was used in this study as an alternative approach to measure temperament without putting cattle through the crush. Apparently, there is no study correlating FZ with performance. Therefore, a pilot trial was conducted to evaluate the correlation between average daily gain (ADG), dry matter intake (DMI) and feed conversion ratio (FCR) of ten Brahman steers. Steers were classified into temperament groups (Docile <2 m; Moderate between 2 to 2.9 m; and Lively ≥3 m). Even though no significant differences were found for ADG (P = 0.65), DMI (P = 0.36), and FCR (P = 0.46), the docile group gained 133 grams/day more than lively counterparts, most likely because of the extra 50 grams consumed. Furthermore, lively steers required an extra 1 kg of feed per kg of gain in comparison to docile animals, 8.24 vs. 7.28 kg FCR, respectively. These results are promising and indicate that FZ could be an efficient way to measure temperament in cattle. Thus, in order to confirm these findings, a new experiment with a more representative number of steers (n = 30) will be conducted.

PALMA, A. S. V. Use of coated urea and monensin on rumen parameters of cattle fed low quality forage. 2020. 68 p. Doctorate Thesis -

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