Search

Sugarcane is an important forage source for dairy cows in tropical countries. However, it provides limited digestible fiber and energy intake, and fat supplementation can be a way to increase energy density and decrease dietary, non-fiber carbohydrates concentrations. We aimed to evaluate the performance, digestion and metabolism of dairy cows in early lactation fed different concentrations of soybean oil (SBO) in sugarcane-based diets. Fourteen primiparous (545±17.2 kg of BW) and eight multiparous (629±26.7 kg BW) Holstein dairy cows were used according to a randomized block design. After calving, diets were randomly assigned to cows within the two parity groups. Diets were formulated with increasing concentrations of SBO (g/kg dry matter (DM)): control (0), low (LSBO; 15.7), medium (MSBO; 44.3) and high (HSBO; 73.4). The study was performed from calving until 84 days in milk, divided into three periods of 28 days each. Dry matter intake (DMI) was affected quadratically in response to SBO addition with the greatest and lowest values of 19.0 and 16.0 kg/day for LSBO and HSBO diets, respectively. The digestibility of potentially digestible NDF was quadratically affected by SBO with the greatest value of 623 g/kg for LSBO diet. Both milk and energy-corrected milk (ECM) production were quadratically affected by SBO inclusion, with greatest ECM values of 27.9 and 27.3 for LSBO and MSBO, respectively. Soybean oil inclusion linearly decreased milk fat concentration by 13.2% from control to HSBO. The CLA t10,c12-18:2 was observed in milk fat only for MSBO and HSBO diets. Soybean oil inclusion did not affect plasma glucose or serum concentrations of total proteins, globulins, albumin, urea nitrogen, beta-hydroxybutyrate, non-esterified fatty acids or insulin. Serum concentrations of total cholesterol, triglycerides and low-density lipoprotein increased with SBO supplementation. Soybean oil inclusion in sugarcane-based diets for early lactation dairy cows from 15.7 to 44.3 g/kg DM can improve energy intake and performance; however, at 44.3 g/kg DM milk fat concentration and ECM decreased. Soybean oil inclusion at 73.4 g/kg DM adversely affected energy intake, fiber digestion and performance of early lactation dairy cows and is not recommended.

Oilseeds offer some protection to the access of ruminal microorganisms and may be an alternative to calcium salts of fatty acids (FA), which are not fully inert in the ruminal environment. This study aimed to evaluate the effects of different sources of FA supplementation on apparent total tract nutrient digestibility, milk yield and composition, and energy balance (EB) of cows during the transition period and early lactation. We compared diets rich in C18:2 and C18:3 FA. Multiparous Holstein cows were randomly assigned to receive one of the four diets: control (n=11); whole flaxseed (WF, n=10), 60 and 80 g/kg (diet dry matter (DM) basis) of WF during the prepartum and postpartum periods, respectively; whole raw soybeans (WS, n=10), 120 and 160 g/kg (diet DM basis) of WS during the prepartum and postpartum periods, respectively; and calcium salts of unsaturated fatty acids (CSFA, n=11), 24 and 32 g/kg (diet DM basis) of CSFA during the prepartum and postpartum periods, respectively. Dry cows fed WF had higher DM and net energy of lactation (NEL) intake than those fed WS or CSFA. The FA supplementation did not alter DM and NDF apparent total tract digestibility, dry cows fed WF exhibited greater NDF total tract digestion than cows fed WS or CSFA. Feeding WS instead of CSFA did not alter NEL intake and total tract digestion of nutrients, but increased milk fat yield and concentration. Calculated efficiency of milk yield was not altered by diets. FA supplementation increased EB during the postpartum period. Experimental diets increased long-chain FA (saturated and unsaturated FA) in milk. In addition, cows fed WS and CSFA had higher C18:1 trans-11 FA and C18:2 cis, and lower C18:3 FA in milk than those fed WF. Furthermore, cows fed CSFA had higher C18:1 trans-11 and cis-9, trans-11 FA than cows fed WS. Although supplemental C18:2 and C18:3 FA did not influence the milk yield of cows, they positively affected EB and increased unsaturated long-chain FA in milk fat.

The objective of this study was to evaluate the nutritional traits and in vitro digestibility of silages from different corn cultivars harvested at two cutting heights. It was evaluated 11 cultivars (Dina 766, Dina 657, Dina 1000, P 3021, P 3041, C 805, C 333, AG 5011, FO 01, Dina co 9621 and BR 205) harvest 5 cm above ground (low) and 5 cm below the intersection of the first ear (high). It was used a random block design (three blocks), arranged in a 11 × 2 factorial scheme. Silages from plants harvested at high cutting height presented average content of dry matter significantly superior to silages from plants harvested at low height. Cultivars FO 01, AG 5011, Dina co 9621 and Dina 766 presented greater content of crude protein than cultivars C 805, P 3041 and P 3021, which presented the lowest contents of this nutrient. The raise in the cut height increased in vitro dry matter true digestibility coefficients and in vitro dry matter digestibility of silage evaluated. The increase in cut height improved nutritive value of silages by decreasing concentrations of fibrous fractions and increasing in vitro dry matter digestibility.Objetivou-se neste estudo avaliar as características nutricionais e a digestibilidade in vitro de silagens de diferentes cultivares de milho colhidas em duas alturas de corte. Foram avaliadas 11 cultivares (Dina 766, Dina 657, Dina 1000, P 3021, P 3041, C 805, C 333, AG 5011, FO 01, Dina co 9621 e BR 205) colhidas 5 cm acima do solo (baixa) e 5 cm abaixo da inserção da primeira espiga (alta). O experimento foi delineado em blocos casualizados (três blocos), arranjados em esquema fatorial 11 × 2. As silagens das plantas colhidas na altura de corte alta apresentaram teor médio de matéria seca significativamente superior às silagens das plantas colhidas na altura de corte baixa. As cultivares FO 01, AG 5011, Dina co 9621 e Dina 766 apresentaram maior teor de proteína bruta, que as cultivares C 805, P 3041 e P 3021, as quais apresentaram os menores teores deste nutriente. A elevação da altura de corte aumentou os coeficientes de digestibilidade verdadeira in vitro da matéria seca e digestibilidade in vitro da matéria seca das silagens avaliadas. O aumento da altura de corte melhorou o valor nutritivo das silagens, diminuindo as concentrações das frações fibrosas e aumentando a digestibilidade in vitro da matéria seca.

Para verificar o efeito da inclusão das interações reprodutor x rebanho e reprodutor x rebanho-ano como fator de ajustamento da heterogeneidade de variância, registros de produção de leite e gordura foram estratificados, com base no desvio-padrão fenotípico da produção de leite ajustada, em duas classes: baixo (1.280kg) desvio-padrão. Três modelos foram utilizados, sem e com interação reprodutor x rebanho e reprodutor x rebanho-ano, em análises de característica única, geral e em cada classe de desvio-padrão. Médias e componentes de variâncias foram maiores na classe de alto desvio-padrão. Na classe de baixo desvio-padrão, a herdabilidade não se alterou com a inclusão dos efeitos de interação no modelo, sendo de 0,34 para produção de leite e de 0,32 para produção de gordura. Na classe de alto desvio-padrão, as herdabilidades foram: 0,37, 0,35 e 0,36, e de 0,35, 0,32 e 0,35, para produção de leite e gordura, nos modelos sem, com interação reprodutor x rebanho e com interação reprodutor x rebanho-ano, respectivamente. A inclusão do efeito de interação reprodutor x rebanho nos modelos foi significativa (PIn order to verify the effect of including the interactions of sire x herd and the sire x herd-year, as a adjust factor of the variance heterogeneity, registers of milk and fat yields were classified into two classes of standard deviation: low (1.280kg), based on phenotypic standard deviation of the milk production adjusted. Three models, without and with interaction of sire x herd and sire x herd-year, were used in the general univariate analyses and in each standard deviation class. Averages and variance components were higher in the high standard deviation. In the class of low standard deviation, heritability didn't alter with the inclusion of the interaction effects in the model, being of 0.34 for milk yield and 0.32 for fat yield. In the class of high standard deviation, heritabilities were: 0.37, 0.35 and 0.36, and of 0.35, 0.32 and 0.35, for milk and fat yield, in the models without and with interaction of sire x herd and with interaction of sire x herd-year, respectively. The inclusion of the interaction of sire x herd was significant (P

Avaliaram-se os efeitos da aplicação de rBST sobre o desempenho produtivo e reprodutivo de vacas da raça Holandesa no início da lactação. Foram avaliadas 41 vacas, dos 60 aos 150 dias de lactação, distribuídas em um delineamento inteiramente ao acaso, em três tratamentos: 1- sem aplicação de rBST (controle); 2- aplicação de rBST 60 dias após o parto (rBST-60); 3- aplicação de rBST 100 dias após o parto (rBST-100). A aplicação de rBST aumentou a produção de leite e a produção de leite corrigida a 4% de gordura em 14,0 e 13,2%, respectivamente, quando administrada aos 60 dias pós-parto. Não se observou efeito da aplicação de rBST sobre a porcentagem e a produção de gordura do leite nem sobre o período de serviço, número de serviços por concepção e taxa de gestação aos 150 dias de lactação. O uso do rBST também não afetou o ganho de peso dos animais durante o período avaliado. A aplicação de rBST aos 60 dias de lactação proporcionou maiores pico de produção e persistência da lactação, sem, no entanto, influenciar o desempenho reprodutivo. A aplicação de rBST aos 100 dias de lactação não aumentou a produção de leite e o desempenho reprodutivo das vacas.The effects of recombinant bovine somatotropin (rBST) on production and reproductive parameters of Holstein dairy cows, from 60 to 150 days of lactation were evaluated. Forty-one cows were assigned to treatments: 1- no rBST application (control), 2- rBST application 60 days post calving (rBST-60), and 3- rBST application 100 days after calving (rBST-100), in a completely randomized design. The rBST application 60 days post calving significantly increased milk production (14%) and corrected milk production (13%). No effects of rBST administration on milk fat production (% and kg/day), days open, number of services/conception and pregnancy rate and on cow weight gain were observed. The rBST application 60 days after calving increased milk production peak and lactation persistence but did not change the reproductive performance. The rBST application at 100 days after calving did not increase milk production or the reproductive performance of cows.

Avaliaram-se os efeitos do escore da condição corporal ao parto sobre a produção e composição do leite, a curva de lactação e o padrão de mobilização de reservas corporais em vacas da raça Holandesa. Foram utilizadas 51 vacas, sendo 13 primíparas e 38 multíparas, distribuídas em delineamento inteiramente ao acaso, segundo a ordem de partos - primíparas e multíparas - e a classe de escore da condição corporal ao parto (ECCP) - classe 1 ECCP igual ou superior a 3,25, e classe 2 ECCP igual ou inferior a 3,0. Para avaliar o padrão de mobilização de reservas corporais, foram formados grupos de vacas em função do ECCP e do nível de produção de leite. Nas primíparas, não foram observados efeitos da ECCP sobre a produção e a composição do leite e sobre a curva da lactação, exceto para porcentagem de gordura. Nas multíparas, as vacas da classe 1 produziram mais leite e mais componentes do leite, e a curva da lactação mostrou pico de produção mais alto. As vacas de maior ECCP e maior produção de leite apresentaram padrão de mobilização de reservas corporais mais acentuado no início da lactação e maior peso corporal no pré-parto e ao parto. O peso corporal e a mudança de peso corporal ao parto e no início da lactação não foram influenciados pelo escore de condição corporal ao parto e pela produção de leite.The effects of body condition at calving on milk yield, milk composition, lactation curve and body tissue mobilization patterns were evaluated in Holstein cows. Thirteen primiparous and 38 multiparous cows were assigned body condition scores at calving (BCC). Those with BCC equal to or greater than 3.25 were assigned to class 1; while those with BCC less than 3.25 constituted class 2. These BCC classes did not affect milk yield, milk composition (except for fat percentage) or lactation curve significantly in primiparous cows. In multiparous cows, however, class 1 individuals had higher total milk yield, higher peak milk yield, higher milk composition percentages and more effective mobilization of body tissue reserves than cows in class 2. Among those cows that had higher BCC, those with more effective mobilization of body tissue reserves at the beginning of lactation had higher milk yields. Cows with higher BCC were heavier at prepartum and at calving in comparison to cows with lower BCC. However, body weight at calving and change in body weight early in lactation were not related to body composition at calving and subsequent milk yield.