Abstract This research article describes the effect of different concentrations of iodine in the teat-dipping before milking and post-dipping solution on milk, urine, thyroid hormone, chemical composition and somatic cell count. Four multiparous cows were distributed in a 4 x 4 Latin square experimental design in a tie-stall system. The treatments were 0.5%, 1%, and 2% iodine and the control was treated with chlorhexidine. The iodine concentration of milk, food and urine was quantified. Thyroid hormones were analyzed by chemiluminescence microparticle immunoassay. Milk composition by differential absorption of infrared waves and somatic cell countby (SCC) flow cytometry. There was no significant effect of iodine concentrations in teats soaking solution before milking on urine iodine concentration and thyroid hormones (T3 and T4). Likewise, no effect of treatments was observed for the contents of protein, fat, lactose, total solids, Milk urea nitrogen and SCC. However, increasing iodine concentrations in the teat soaking solution before milking linearly increased the iodine concentration in milk. Therefore, the iodine concentration in the pre-milking and post-dipping solutions can change the iodine concentration in the milk.

ABSTRACT We evaluated the association of monthly milk urea N (MUN) concentrations before conception and days open in high-producing dairy cows from commercial herds in Southern Brazil. Other herd traits were also investigated regarding their relationship with days open. A database containing 16,569 monthly test-day records (obtained from 3,926 lactations of 2,145 cows) for productive, reproductive, and milk quality data was assembled from three different herds. Maximum MUN before conception was divided into quartiles as follows: ≤15.5 mg/dL (1), from 15.6 mg/dL to 18.0 mg/dL (2), from 18.1 to 20.5 mg/dL (3), and >20.5 mg/dL (4). When cows calved in spring and winter, days open averaged (mean±SE) 171.2±2.71 and 155.4±2.31, corresponding to an increase in 12 and 2%, respectively, related to cows that calved in summer (152.7±2.44). When cows calved in fall, a 12% reduction in days open (135.5±1.79) compared with cows that calved in summer was observed. The estimated regression coefficients showed that multiparous cows are expected to have an increase of 12 and 6% in days open when compared with primiparous and secondiparous cows, respectively. Days open were positively associated with the highest MUN value obtained until conception. Cows in the highest quartile of maximum MUN (>20.5 mg/dL) had more days open (184.6±2.93) than cows in quartiles 1, 2, and 3 (123.7±2.12, 150.2±2.16, and 160.5±2.29, respectively), which represents reductions of 40, 21, and 14%, respectively. These results suggest that a maximum MUN concentration before conception higher than 15.5 mg/dL may negatively impact the fertility of high-producing dairy cows.

ABSTRACT The present investigation aimed to evaluate the population structure and inbreeding of Holstein herds in southern Brazil. To carry out the analysis, the Associação Paranaense de Criadores de Bovinos da Raça Holandesa (APCBRH) in Brazil provided the data, which consisted of a pedigree file of 206,796 animals born between 1970 and 2014. Results regarding the following parameters were determined: pedigree integrity, effective number of founders, effective number of ancestors, generation interval, inbreeding coefficient, realized effective population size, and average relatedness coefficient. POPREP and ENDOG v.4.5 software packages were employed to estimate these parameters. Based on the data set, the mean generation interval was found to be 6.3 years, and the average inbreeding coefficient, related to inbred animals, was 4.99%. Furthermore, the realized effective population size varied throughout the time period, ranging from 22 to 114, whereas the rate of inbreeding in this same period showed a decreasing trend towards the later years in the period until 2014. Upon evaluation, average relatedness coefficient was estimated to be 0.71%. Moreover, the effective number of founders and ancestors were estimated as 418 and 400 animals, respectively. According to the level of inbreeding observed, it could be noticed that genetic diversity remains elevated, which will be important to the genetic progress in the Holstein breeding program in Southern Brazil.

Resumen Antecedentes: La demanda por alimentos naturalmente enriquecidos se ha venido incrementado en todo el mundo. A través de la nutrición animal es posible incorporar moléculas nutracéuticas en la leche. El uso de estas moléculas pretende mejorar la salud humana. Objetivo: Evaluar los efectos de la peletización y la monensina sobre la ingesta, digestibilidad de la materia seca (DM) y nutrientes, producción de leche, composición y perfil de ácidos grasos (FA) en leche de vacas en pastoreo que consumen alimento concentrado formulado con linaza molida (GF). Métodos: Cuatro vacas Holstein fueron distribuidas en los siguientes tratamientos: 1) ración conteniendo GF; 2) GF + 32,93 mg/Kg de monensina (GFM); 3) GF en pellets (GFP); 4) GF en pellets + 32,93 mg/Kg de monensina (FMP). Resultados: Los tratamientos no mostraron efectos en el consumo y digestibilidad de la DM y nutrientes, excepto por el consumo de extracto etéreo, con una reducción del 28% en las raciones peletizadas. La monensina incrementó la concentración de ácido linoleico conjugado (CLA) en 47%. La peletización aumentó el contenido de CLA (70%), FA poliinsaturados (PUFA; 25%) y FA monoinsaturados (16%); y redujo las concentraciones de C18 en 19%, y FA saturados total en 14%. Conclusión: El peletizado y la monensina no alteran la ingesta de alimento ni la digestibilidad de la DM y nutrientes. El proceso de peletizado aplicado a concentrados que contienen linaza mejora la calidad de los ácidos grasos de la leche.

Abstract Background: Demand for naturally enriched foods is increasing worldwide. Animal nutrition allows incorporating nutraceutical molecules into milk. These molecules are intended for improving human health. Objective: To evaluate the effects of pelleting and monensin addition to the diet on intake, digestibility of dry matter (DM) and nutrients, milk yield and composition, and fatty acids (FA) profile in cows kept on pasture and supplemented with concentrate containing ground flaxseed (GF). Methods: Four Holstein cows were assigned to the following treatments: 1) concentrate with GF; 2) GF + 32.93 mg/Kg monensin (GFM); 3) GF pelleted (GFP); 4) GF pelleted + 32.93 mg/Kg monensin (FMP). Results: Treatments did not show effects on digestibility of dry matter (DM) and nutrients or feed intake, with the exception of ether extract intake, which was reduced by 28% with pelleting. Addition of monensin increased the conjugated linoleic acid (CLA) concentration by 47%. Pelleting increased the concentrations of CLA (70%), polyunsaturated FA (PUFA; 25%), and monounsaturated FA (MUFA; 16%), and reduced the concentrations of steric acid (C18) in 19% and total saturated FA (SFA; 14%). Conclusion: Pelleting and monensin does not alter feed intake and digestibility of DM and nutrients. Pelleting of concentrate feed containing flaxseed improves milk FA quality.

Resumo Antecedentes: A procura por alimentos naturalmente enriquecidos tem aumentado por parte dos consumidores. Através da nutrição animal é possível incorporar ao leite moléculas nutracêuticas, essas moléculas são conhecidas por melhorarem a saúde humana. Objetivo: Avaliar os efeitos da peletização e monensina sobre o consumo, digestibilidade da matéria seca (DM) e nutrientes, produção de leite, composição e perfil de ácidos graxos (FA) no leite de vacas em pastejo e suplementadas com concentrado contendo linhaça moída (GF). Métodos: Quatro vacas Holandesas foram distribuídas nos tratamentos: 1) concentrado contendo GF; 2) GF + 32,93 mg/Kg de monensina (GFM); 3) GF peletizado (GFP); 4) GF peletizado + 32,93 mg/Kg de monensina (FMP). Resultados: Os tratamentos não apresentaram efeitos sobre consumo e digestibilidade da DM e dos nutrientes, exceto para o consumo de extrato etéreo, com redução de 28% com a peletização do concentrado. A adição de monensina aumentou a concentração de ácido linoleico conjugado (CLA) em 47%. A peletização aumentou os teores de CLA (70%), FA poli-insaturados (25%) e FA monoinsaturados (16%); e reduziu as concentrações de C18 em 19% e AG saturados totais em 14%. Conclusão: Peletização e monensina não alteram o consumo e digestibilidade da DM e dos nutrientes. O processo de peletização aplicado em concentrados contendo linhaça melhora a qualidade dos FA do leite.

Twenty-four Saanen goats (15 multiparous and 9 primiparous) from 21 days prepartum to 200 days in lactation were used to evaluate milk yield and composition. Animals were randomly distributed in a 3 × 2 factorial arrangement (3 diets × 2 parity orders) and fed a 40:60 forage:concentrate diet composed of soybean meal, soybean meal + dry yeast or dry yeast as protein source, plus ground corn, mineral supplement and corn silage. The protein source did not influence the body weight of pre and postpartum goats. Prepartum, postpartum and postpeak dry matter intake (DMI) were not altered by diets. However, goats fed the diet containing dry yeast as protein source had lower DMI in late lactation. Milk yield and feed efficiency were not affected by diets. Milk components, acidity and somatic cell count were not influenced by diets during all lactation phases. However, fat and total solid contents postpartum were higher for primiparous goats and somatic cell count postpeak was lower for multiparous goats. Dry yeast can be used to replace soybean meal in diets for lactating Saanen goats.

The present study was conducted to determine the relationship between milk urea nitrogen (MUN) and milk yield, fat and protein contents, breed and season effects, parity and days in milk in dairy cows from Paraná State, Brazil. A total of 127,428 test-days from 16,013 dairy cows belonging to 96 herds enrolled in an official milk recording program were analyzed. Multivariate mixed model methodology was used to determine the relationship between MUN and the fixed effects and the covariable milk production. Milk urea nitrogen averaged 14.45±4.60 mg/dL. Positive and intermediate association between MUN and milk yield (r = 0.34) were found. Holstein cows showed lower MUN adjusted means than crossbred, Jersey, and Brown Swiss cows: 14.18 vs. 15.49, 16.12, and 17.62 mg/dL, respectively. First-lactation cows showed higher MUN values than second-lactation and older cows: 16.16 vs. 15.95, and 15.45 mg/dL, respectively. MUN test-days collected during the winter were higher than those collected in the other seasons. The effects of the lactation stage on MUN were significant, with the highest MUN values observed in the sixth month of lactation. High-producing dairy cows showed higher milk urea concentrations but several environmental factors may contribute to reduce this important parameter of diet utilization efficiency.

Objetivou-se avaliar o efeito da substituição da silagem de milho pela silagem a rama da mandioca na produção e do leite. Foram utilizadas doze vacas em lactação em delineamento experimental inteiramente casualizado em bloco com quatro tratamentos e três repetições por bloco. A silagem de milho (SM) foi substituída pela silagem de rama de mandioca (SRM) em níveis 0, 20, 40 e 60%. A substituição da silagem de milho em diferentes níveis de SRM teve pouco efeito nos parâmetros estudados. A densidade do leite diminuiu com o aumento dos níveis de substituição. Os ácidos graxos 4:0 e 6:0 apresentaram comportamento quadrático, enquanto que os ácidos 8:0, 10:0, e 15:0 apresentaram comportamento linear quando o conteúdo de SRM foi aumentado. A substituição de 20 a 60% de SRM resultou em diminuição significativa dos custos de alimentação em comparação a silagem de milho. Os resultados sugeriram que a SRM foi um bom substituto da SM para vacas leiteiras.

This study aimed to evaluate the effect of corn silage (CS) replacement by cassava's foliage silage (CFS) on the production and quality of milk. Twelve lactating dairy cows were used in a randomized block experimental design with four treatments and three repetitions per block. CS was replaced by CFS at the levels of 0, 20, 40, and 60%. The replacement of CS by different levels of CFS had very low effect on the variables studied. Milk density decreased when the replacement level was increased. Fatty acids 4:0 and 6:0 presented a quadratic behavior, while fat acids 8:0, 10:0, and 15:0 presented a linear behavior as their concentrations fell when CFS diet content was increased. The CS replacement by 20% until 60% CFS resulted a significant decrease in the feeding costs. The results suggested that CFS was a good replacement of CS for dairy cows.