AVALIAÇÃO E CORRELAÇÃO DE PARÂMETROS FISIOLÓGICOS E ÍNDICES BIOCLIMÁTICOS DE VACAS HOLANDÊS EM DIFERENTES ESTAÇÕES

http://dx.doi.org/10.5902/2236117010747The objective of this study was to determine the physiological parameters of Holstein cows in milking during the winter and spring season and correlate these parameters with the bioclimatic indexes. We used nine Holstein cows in a completely randomized delimitation in a subdivided plot arrangement with repeated measures in time. Data were collected during the winter and spring, which were measured respiratory rate (RR), heart rate (HR), superficial temperature (ST) and rectal temperature (RT) from animals, besides the air temperature, the relative humidity and black globe temperature. It was calculated the temperature and humidity index (THI), the Black Globe Temperature and Humidity Index (BGTH) and Radiant Heat Load (RHL). The THI, BGTH and RHL showed increases in the afternoon suggesting an environment susceptible to stress. There were no statistical differences (P>0.05) between the seasons of winter and spring for any of the physiological variables. Only HR was above physiological limits for cattle. HR, RR and ST showed significant positive correlation (P0,05) entre as estações do inverno e da primavera para nenhuma das variáveis fisiológicas. Somente a FC mostrou-se acima dos limites fisiológicos para bovinos. A FC, FR e TS apresentaram correlação positiva e significativa (P<0,01) com o ITU e o ITGU e a CTR. Contudo, não foi detectado estresse térmico nos animais na estação de inverno e da primavera, embora os parâmetros fisiológicos tenham apresentado correlação com os índices bioclimático

Tifton 85 bermudagrass (Cynodon sp.) silage as a replacement for Tifton 85 hay to feed lactating cows

The objective of the study was to evaluate the replacement of Tifton 85 hay (TH) for Tifton 85 silage (TS) in the diets of lactating cows. Five Holstein cows in middle of lactation were allocated in a 5 × 5 Latin square design and each experimental period lasted 18 days (12 days for adaptation and six days for collection). Treatments consisted of replacement of 0, 25, 50, 75, and 100% of TH for TS. The intake and digestion of nutrients, microbial protein synthesis, milk yield and composition, and the economic viability of the diets were evaluated. The intakes of dry matter, organic matter, and ether extract had a positive linear effect and the digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, acid detergent fiber decreased linearly with increasing participation of TS. Milk production and composition and microbial protein synthesis were not affected. Regarding economic viability, the treatment with 100% hay produced better results, with better gross margin. The Tifton 85 silage can be used as a replacement for Tifton 85 hay up to 100% without changing the milk production and composition of Holstein cows

Effects of Black Wattle (Acacia mearnsii) Condensed Tannins on Intake, Protozoa Population, Ruminal Fermentation, and Nutrient Digestibility in Jersey Steers

The objective of this study was to evaluate the effect of inclusion of condensed tannins (CT) from black wattle (Acacia mearnsii) on feed intake, ruminal protozoa population, ruminal fermentation, and nutrient digestibility in Jersey steers. Five ruminally-cannulated steers were used in a 5 &times; 5 Latin square design, with five periods of 20 days each (14 days for diet adaptation and six days for sample collection per period). Treatments were composed of dietary inclusion levels of condensed tannins at 0, 5, 10, 15, and 20 g/kg of diet dry matter. Intakes of dry matter, organic matter, ether extract, crude protein, neutral detergent fiber, and total digestible nutrients were not affected by condensed tannins. The ruminal pH was reduced linearly with tannin levels. Ruminal ammonia nitrogen concentration was not affected by tannins. Tannins reduced the molar proportion of acetate and did not affect the ruminal protozoal population, which might be related to the low doses used. Digestibilities of dry matter, organic matter, and neutral detergent fiber were not altered; however, there was a linear reduction in crude protein digestibility. Based on these results, CT extracts from black wattle are not recommended for improving nutrient utilization in steers at the tested levels

Tifton 85 bermudagrass (Cynodon sp.) silage as a replacement for Tifton 85 hay to feed lactating cows

ABSTRACT The objective of the study was to evaluate the replacement of Tifton 85 hay (TH) for Tifton 85 silage (TS) in the diets of lactating cows. Five Holstein cows in middle of lactation were allocated in a 5 × 5 Latin square design and each experimental period lasted 18 days (12 days for adaptation and six days for collection). Treatments consisted of replacement of 0, 25, 50, 75, and 100% of TH for TS. The intake and digestion of nutrients, microbial protein synthesis, milk yield and composition, and the economic viability of the diets were evaluated. The intakes of dry matter, organic matter, and ether extract had a positive linear effect and the digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, acid detergent fiber decreased linearly with increasing participation of TS. Milk production and composition and microbial protein synthesis were not affected. Regarding economic viability, the treatment with 100% hay produced better results, with better gross margin. The Tifton 85 silage can be used as a replacement for Tifton 85 hay up to 100% without changing the milk production and composition of Holstein cows

Use of dried brewers' grains instead of soybean meal to feed lactating cows

ABSTRACT The objective of this study was to determine the optimal level of dried brewers' grains (DBG) to replace soybean meal in diets for lactating Holstein cows. Five cows, around 88±28 days in milk, were distributed in a 5 × 5 Latin square design and fed diets containing different levels of DBG (0, 25, 50, 75, and 100%). The forage:concentrate ratio of the diet was 50:50. Feed intake, dry matter, nutrient digestibility, microbial synthesis, milk production and composition, and the economic viability of the diets were evaluated. There was reduction in dry matter intake and, consequently, in crude protein and non-fiber carbohydrates with increased levels of DBG. This occurred due to physical limitation of rumen caused by increased neutral detergent fiber intake. Ether extract intake also increased with levels of DBG due to higher concentrations of this nutrient in the diet. Apparent dry matter, organic matter, ether extract, and neutral detergent fiber digestibility increased with replacement of soybean meal by DBG. Milk production showed a quadratic effect and the levels of fat, protein, and total solids reduced linearly. Each 1% of soybean meal replaced by DBG in concentrate led to a reduction of 0.04, 0.02, and 0.06 g kg-1 of milk fat, protein, and total solids, respectively. The milk production efficiency increased linearly and the microbial synthesis efficiency was not affected. The economic return increased along with the DBG levels. Thus, DBG levels replacing up to 75% of soybean meal can be used to feed lactating cows, since it provides improvements in digestibility, milk production efficiency, and economic return without affecting microbial efficiency

In vitro evaluation of Lactobacillus plantarum as direct-fed microbials in high-producing dairy cows diets

The objectives of this study were: 1) to compare the effects of live yeast (LY), yeast fermentation product (YFP), a mix of Lactobacillus acidophilus and Propionibacterium freudenreichii (MLP), and Lactobacillus plantarum included as additives in dairy cows’ diets on in vitro ruminal fermentation and gas production (GP); and 2) to evaluate the effects of L. plantarum as direct-fed microbials (DFM) in dairy cows’ diets on in vitro ruminal fermentation, GP, nutrient digestibility, and N metabolism. Three experiments were carried out: Exp. 1 had the objective to compare all additives regarding ruminal fermentation parameters: an Ankom GP system was used in a completely randomized design, consisting of four 48 h incubations, and eight replications per treatment. There were eight treatments: a basal diet without additive (CTRL) or with one of the following additives: LY, YFP, MLP, or L. plantarum at four levels (% of diet Dry Matter (DM)): 0.05% (L1), 0.10% (L2), 0.15% (L3), and 0.20% (L4). In Exp. 2, a batch culture was used to evaluate ruminal fermentation, and CO2 and CH4 production using the same treatments and a similar experimental design, except for having 16 replications per treatment. Based on Exp. 1 and 2 results, Exp. 3 aimed at evaluating the effects of the L. plantarum on ruminal true nutrient digestibility and N utilization in order to evaluate the use of L. plantarum as DFM. The treatments CTRL, MLP, L1, and L2 were used in a replicated 4 × 4 Latin square design using a dual-flow continuous culture system. Data were analyzed using linear and nonlinear regression; treatment means were compared through contrasts, and L treatments in Exp. 1 and 2 were tested for linear, quadratic, and cubic effects. In Exp. 1, all treatments containing additives tended to reduce OM digestibility as well as reduced total volatile fatty acids (VFA) concentration and total GP. The YFP had greater OM digestibility than LY, and MLP treatment had greater total VFA concentration compared to L. plantarum treatments. In Exp. 2, additives reduced CO2 production, and there were no major differences in CH4. In Exp. 3, all additives reduced NH3 -N concentration. In conclusion, pH and lactate concentration were not affected in all three experiments regardless of additive tested, suggesting that these additives may not improve ruminal fermentation by pH modulation; and L. plantarum may improve ruminal N metabolism when used as DFM in high-producing dairy cows’ diets, mainly by reducing NH3 -N concentration.UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni