Productive, thermoregulatory, and hormonal responses of dairy goats supplemented with selenium-enriched yeast in the Brazilian semi-arid region.

The aim of this study was to evaluate the effect of adding selenium-enriched yeast (SE) in the diet of dairy goats during 60 days of lactation and its effect on productive, thermoregulatory, and hormonal responses of animals managed in a semi-arid region. Sixteen Saanen × Toggenburg crossbred goats were used in a completely randomized design. Goats were weighed, and their milk yield was monitored weekly. Before the animals entered the treatments and at every 20-day milk producing, blood samples were collected to determine the SE levels. At 20, 40, and days of the lactation cycle, individual milk samples were collected to determine composition, casein, urea nitrogen, and selenium content. Measurements of respiratory rate (RR), rectal temperature (RT), coat surface temperature (CST), and epidermal temperature (ET) were performed weekly during the experimental period in two shifts, one in the morning (9 am) and the other in the afternoon (3 pm). No difference (P > 0.05) was detected for body weight, milk yield, composition, selenium concentration, and urea nitrogen. Lower RR and ET (P < 0.05) were observed for animals that received SE supplementation. Thyroid hormone concentrations were similar between treatments (P > 0.05). The positive results of the SE supplementation were concentrated in thermoregulatory responses, and there was no effect on productive, hormonal responses, and plasmatic concentration of selenium in the milk. The SE supplementation for dairy goats managed in a Brazilian semi-arid region was able to promote reduction of RR and coat temperatures.

Organic selenium supplementation on metabolic profile of dairy goats.

The aim of this study was to evaluate the effect of organic selenium (SE) supplementation on blood constituents related to hematology and serum biochemistry of dairy goats in the productive phase. A total of 16 lactating Saanen × Toggenburg crossbred goats, aged between 2 and 3, lactating, nonpregnant, clinically healthy, and having a body weight (BW) of 40.75 ± 8.31 kg were selected for this study. Higher SE concentrations were observed on the 42nd day of supplementation, and on the 63rd day, the SE concentrations were similar ([Formula: see text]) to the 21st and 42nd days. There was no interaction for plasma constituents comparing treatment effects and days of supplementation ([Formula: see text]). SE supplementation reduced ([Formula: see text]) plasma proteins with a gradual increase in available SE. There was no difference ([Formula: see text]) for the blood count comparing the effects of treatment and days of supplementation. There was no interaction ([Formula: see text]) for serum biochemical constituents between treatments and periods, except for urea ([Formula: see text]). Animals that received SE supplementation had similar plasma urea concentrations before and after supplementation, while animals that did not receive SE in the diet had increased serum urea concentrations. The main action of selenium in metabolism occurred in the reduction of plasma proteins and urea levels, which leads us to conclude that it influenced protein metabolism. Finally, hematology, liver function, and energy metabolism are not affected by selenium supplementation in dairy goats reared in semiarid conditions.

Effect of a 60-day organic selenium-supplemented diet on the decrease of somatic cell counts in goat milk.

Selenium is an important element in nutrition, showing great potential in the udder health of dairy goats and in the control of subclinical mastitis. However, there are few studies that evaluated the influence of selenium supplementation on subclinical mastitis in goats. The aim of this study was to evaluate the incidence of subclinical mastitis in dairy goats supplemented with organic selenium (Se yeast) in a semi-arid region. Sixteen Saanen × Toggenburg crossbred lactating goats were allocated randomly into two treatments: with and without addition of organic selenium (Se) to the concentrate. Milk samples were collected every 20 days from each udder half to determine the somatic cell count (SSC), chloride content, pH, electrical conductivity, microbiological isolation, composition, and selenium contents. The highest serum selenium concentrations in the blood of these goats occurred at 42 days of supplementation (P < 0.001). Goats which received organic selenium supplementation had higher serum selenium concentrations (P < 0.05). The milk composition variables did not differ (P > 0.05) between the tested treatments, teats, and collections. After 60 days of supplementation, a difference was observed (P < 0.05) between treatments for SSC, chloride content, and pH. Addition of organic selenium to the diet of dairy goats after 60 days of supplementation was promising in reducing the somatic cell count, consequently improving milk quality.

Alternative additives associated in the feeding of laying hens: performance, biometrics, bone traits, and economic evaluation-an unsupervised machine learning approach.

Given the current bans on the use of some growth promoting antibiotics in poultry nutrition, the need to use alternative additives which could replace traditional promoters in diets has arisen. The objective of this study was to evaluate the effect of alternative additives, associated or not, in replacing the antibiotic growth promoter in the diets of laying hens on performance, egg quality, biometry, bone characteristics, and economic viability. A total of 378 birds at 97 weeks of age, weighing 1691 ± 80g with an average production of 79.96 ± 4.9%, were randomly distributed and submitted to different diets: negative control - NC (no additive); positive control - PC, conventional growth promoter (Enramycin); associated organic acids (OA); symbiotic (S); Essential oil (EO); OA + S; and S+EO. The diet did not influence (P > 0.05) performance, egg quality, biometry, and bone traits. However, the use of alternative additives and their associations with the exception of S+OA, provided better economic indices when compared to NC and CP. The first component showed a negative relationship between feed conversion per mass and dozen eggs with gut length, Seedor index, egg production, and egg mass; the second component showed a positive relationship between yolk, pancreas, proventriculus, and gizzard; and, finally, the third component showed that feed consumption has a negative relationship with bone strength and deformity. The first two canonical functions were significant and discriminated 100% of the differences between the diets. Moreover, 50% of the birds were correctly classified in their group of origin, in which the positive control group (83.3%) and OA+S presented the highest rates of correct responses (66.7%). Bone deformity and bowel length were the only two variables with discriminatory power. Natural growth promoters alone or in association do not harm performance, egg quality, digestive organs biometry or bird bone characteristics, in addition to promoting greater economic return. Thus, they can be considered possible substitutes for traditional antibiotics. Finally, unsupervised machine learning methods are useful statistical techniques to study the relationship of variables and point out the main biomarkers of poultry production.