Fernanda Alves de Paiva

Influência do transporte e mudança de local de manejo nas variáveis fisiológicas e produtivas de cabras Alpinas

Estudaram-se o efeito do transporte e a mudanca de local de manejo sobre a producao e a composicao do leite e sobre as variaveis fisiologicas, utilizando-se 12 cabras da raca Alpina em final de lactacao. Semanalmente, foram mensuradas a producao e composicao do leite e a contagem de celulas somaticas, alem do volume do leite residual apos administracao de ocitocina. Foram colhidas amostras de sangue para dosagem hormonal (cortisol) e enzimatica (glicose) no plasma no dia do transporte: antes (7h10min) e apos (8h20min, 8h30min e 10h30min) o transporte. Nas tres semanas subsequentes ao transporte, tambem foram colhidas amostras de sangue as 8h20min. Obtiveram-se teores mais elevados (P<0,05) de cortisol e glicose apos o transporte e a mudanca de local de manejo, e menor producao de leite (P<0,05) um dia apos o evento. Porcentagem de gordura (P<0,05) e contagem de celulas somaticas apresentaram diferencas significativas (P<0,05) apos o transporte. Os resultados permitem concluir que o transporte e um agente estressor que pode, momentaneamente, influenciar a producao animal.

Efeito do manejo de fornecimento de colostro na imunidade passiva, cortisol e metabólitos plasmáticos de bezerros Holandeses

The influence of colostrum supply on immunoglobulin G, glucose, total protein, triglycerides, lactate and cortisol concentrations of 18 Holstein calves, was evaluated. Calves were allotted to three treatments, T1 - calves were separated from cows 6h after birth, nursing 30 minutes a day in their mothers, twice a day in the first three days; T2 - calves were separated 6h after birth, and in the first three days they received colostrum through nipple bottles twice a day, 2l/meal; and T3 - calves remained all the time with cows during the first three days. Blood samples were taken at times 0; 12; 24; 48; 72 and 96h after birth. IgG levels were higher in T3 than in T1 at 24h (P<0.10). Glucose levels were higher in T3 than in the other treatments (P<0.10). Total protein levels in T2 were higher than in T1 (P<0.10). Cortisol and lactate concentrations at birth were higher in all treatments (P<0.10). Howewer, T2 would be more indicated for its feasibility.

Influência do balanço cátion-aniônico da dieta no rúmen e no desempenho de ovinos

The effect of dietary cation-anion balance (DCAB) on dry matter intake, daily weight gain, feed conversion efficiency, rumen pH and rumen volatile fatty acid profile in Santa Ines sheep was studied. Dietary treatments were formulated combining sodium sulphate and sodium bicarbonate in appropriate ratios to achieve DCAB balance of -160, -40, 140, 250 and 500 mEq/kg dry matter. Twenty five male lambs were assigned to the five treatments in a randomized block design for a 75-day feeding trial. Increasing DCAB was associated with increasing voluntary dry matter intake, daily weight gain, feed conversion efficiency and rumen pH (P<0.05); but DCAB did not affect the volatile fatty acid profile in the rumen.

Morfometria e distribuição de leite alveolar e cisternal na glândula mamária de vacas Holandesa e Girolanda

The milk distribution in alveolar and cisternal portions and the mammary gland morphometry were studied using 14 cows, being seven Holstein and seven Girolanda, with same parity and days in lactation, and milked twice a day. Milk yield was measured everyday, whereas alveolar and cisternal fractions were determined once a week. During the experiment, ultrasound scan measurements and morphometrical measures of the mammary gland were also performed. Girolanda cows had udder and teats larger than Holstein cows. Diameter, wall thickness, and length of the teat channel measured from ultrasound images were higher in Girolanda group, but cisternal area of the mammary gland was larger in Holstein cows. No differences in milk yield and cisternal and alveolar milk fractions between the studied breeds were observed.

Efeitos da fonte de enxofre sobre a população de protozoários e degradabilidade no rúmen

This research was carried out at FZEA/USP to compare the effects of different sulphur sources in diets of Nellore cattle on ruminal parameters. Eight steers were rumen cannulated and submitted to four treatments, using the following sulphur sources: control (no supplement), elemental sulphur, methionine, and carboquelated. Animals were fed a total ration using sugarcane as the roughage. The proportion roughage:concentrate was 40:60. The experimental period lasted 76 days, divided in four 19-days sub-periods. The first 14 days of each sub-period were used to adapt the animals to the diet and the last five days to collect the samples. During the sample period, ruminal liquid was sampled to protozoa count and pH determination. Also, nylon bags were incubated in rumen to determinate the degradability of dietary dry matter, crude protein, and acid and neutral detergent fiber. Treatments did not affect dietary dry matter, crude protein, acid and neutral detergent fiber degradability, and the ruminal pH. However, carboquelated provided the higher total amount of ciliate protozoa and methionine provided the lowest values. Carboquelated can be a good alternative to supplement sulphur to bovines in a feedlot.

Resposta em parâmetros sanguíneos e urinários de vacas leiteiras ao aumento no balanço cátion-aniônico da dieta

The effect of four levels of cationic diets on acid-basic parameters of blood and the urinary pH were studied in dairy cattle. In order tomanage the dietary cation-anion balance (DCAB) different concentrations of sodium bicarbonate were added to diets, obtaining the following treatments: +150, +250, +400, and +500mEq/kg dry matter. The experiment was performed during the summer, totalizing 72 days, using eight Holstein cows after the lactating peak, distributed in 4 x 4 replicated latin square, with 18 days in each period. The urinary pH and the blood parameters (bicarbonate, pH, total CO2, and pCO2) linearly increased (P 0.05) by DCAB. The chloride concentration in blood linearly decreased (P<0.01) with the DCAB increase. The DCAB increase affected the acid-base status of cows, promoting an alkalinogenic effect, what could lead to significant differences on animal performance.

Efeito do manejo de aleitamento nos níveis de cortisol no metabolismo e na produção de leite de vacas holandesas

The effects of different milking management on metabolism, cortisol levels, and milk yield of Holstein cows were investigated in this trial. Eighteen Holstein cows and calves were randomly assigned to one of the following three treatments: T1) cows were separated from their calves 6 h after parturition but reunited with them for two daily periods of 30 minutes each; T2) cows were separated from their calves 6 h after parturition; or T3) cows were maintained with their calves during the first three days of lactation except at milking times. Blood samples were collected 168 h before parturition, at parturition (0 h) and at 24, 48, 72 and 96 h after parturition and analyzed for glucose, triglycerides, total protein, and cortisol. Milk yield was measured twice a day and the percentage of residual milk was estimated based on the first two milkings after weaning. Although plasma cortisol levels were greater at parturition (0 h) compared to the remaining sampling points, no significant differences were observed among treatments. Cows on T2 yielded more milk than those on T1 and T3 during the first four days of lactation with no difference in milk production thereafter. After weaning, the percentage of residual milk was higher on T1 and T3 showing that the exclusive use of milking machine after a nursing period appeared to negatively affect milk ejection. Concentration of plasma glucose was lower at 72 h on T2 while that of triglycerides was lower at 72 and 96 h on T3. The studied managements did not influence the cortisol levels and metabolism of cows and did not prejudice the milk production after the colostral period.

Balanço cátion-aniônico da dieta na composição do leite

Eight lactating Holsteins cows were distributed in a 4x4 replicated Latin square in the summer for 72 days. The objective of this research was to study the effect of four levels of cationic diets on the composition and physic-chemistries parameters of milk in cows after the lactation peak. For dietary cation anion balance manipulation, different concentrations of the sodium bicarbonate were added in the diets and the following treatments were obtainned: +150, +250, +400 e +500mEq kg -1 DM. The diets did not affect fat percentage and variables, density and crioscopic indice in the milk. Milk pH increased linearly and acidity decreased cubically with increased of dietary CAB.