F. Zanferari

Effects of chitosan on ruminal fermentation, nutrient digestibility, and milk yield and composition of dairy cows

Our objective was to evaluate the effects of providing increasing levels of chitosan on nutrient digestibility, ruminal fermentation, blood parameters, nitrogen utilisation, microbial protein synthesis, and milk yield and composition of lactating dairy cows. Eight rumen-fistulated Holstein cows [average days in lactation = 215 ± 60.9; and average bodyweight (BW) = 641 ± 41.1 kg] were assigned into a replicated 4 × 4 Latin square design, with 21-day evaluation periods. Cows were assigned to be provided with four levels of chitosan, placed into the rumen through the fistula, as follows: (1) Control: with no provision of chitosan; (2) 75 mg/kg BW; (3) 150 mg/kg BW; and (4) 225 mg/kg BW. Chitosan had no effect on dry matter intake (P > 0.73); however, chitosan increased (P = 0.05) crude protein digestibility. Propionate concentration was increased (P = 0.02), and butyrate, isobutyrate, isovalerate and acetate : propionate ratio were decreased (P ≤ 0.04) by chitosan. Chitosan had no effect (P > 0.25) on acetate, pH and NH3 ruminal concentration. Glucose, urea, and hepatic enzyme concentrations in the blood were similar (P > 0.30) among treatments. Nitrogen balance was not affected, but chitosan increased milk nitrogen (P = 0.02). Microbial protein synthesis was not affected by chitosan (P > 0.44). Chitosan increased (P = 0.02) milk yield, fat-corrected milk, protein and lactose production. Chitosan changes ruminal fermentation and improves milk yield of lactating dairy cows; therefore, we conclude that chitosan can be used as a rumen modulator instead of ionophores in diets for dairy cows.

Productive performance of simmental dairy cows supplemented with ricinoleic acid from castor oil.

The aim of this study was to evaluate the performance and blood parameters of Simmental dairy cows, supplemented with 2 g/day of ricinoleic acid (RA) in diet. Forty Simmental dairy cows in mid lactation, individually housed in stable type tie-stall, were used. The animals were randomly assigned to two treatments: 0 or 2 g of RA/animal/day. The experimental period consisted of 42 days divided into two 21-day. It was observed reduction in dry matter intake (DMI), increased milk, fat and FCM (fat corrected milk) yield, as well as increased of fat content of milk in cows that received RA in diets. No effects were observed for red and white blood cells and blood metabolites. Supplementation of RA improves performance of dairy cows in mid lactation.

Different durations of whole raw soybean supplementation during the prepartum period: Milk fatty acid profile and oocyte and embryo quality of early-lactating Holstein cows

The objective of this study was to evaluate different durations of whole raw soybeans (WS) supplementation during the prepartum period on nutrient digestibility, milk yield and composition, energy balance, blood metabolites, and oocyte and embryo quality of transition cows. Thirty-one Holstein cows were used in a completely randomized design and assigned to 4 experimental groups (G): G90, G60, G30, and G0 (control), supplemented with a diet containing 12% of WS from 90, 60, 30, and 0 d relative to the calving date, respectively. Cows were dried off 60 d before the expected calving date. After parturition, all cows were fed a diet containing 12% of WS until 84 DIM. Blood samples were collected on d -49, -35, -21, -14, -7, 0, 7, 14, 21, 35, and 70 relative to partum. Ovum pick-ups were performed on d 21 ± 3, 42 ± 7, 63 ± 7, and 84 ± 7 of lactation. Different durations of WS supplementation did not affect DMI and apparent total-tract digestibility in either the pre- or postpartum periods. Duration of WS supplementation had no effect on milk yield and composition nor energy balance of cows. However, the duration of WS supplementation had several effects on milk fatty acid (FA) profile of cows, including a linear decrease in concentrations of cis-9 C18:1, unsaturated C18, total monounsaturated, and unsaturated FA. Further, the milk contents of cis-9,cis-12 C18:2 FA, cis-9,trans-11 C18:2 FA, and total polyunsaturated FA were increased when WS were fed to cows from 30 d but not from 60 or 90 d of the expected calving date. The length of WS supplementation in the prepartum period linearly increased blood cholesterol concentration of cows during the prepartum period, but it had no effect on blood glucose and nonesterified FA concentrations in the pre- and postpartum periods. Duration of WS supplementation during the prepartum period increased the average number of grade 2 oocytes, notably in G60, but it had no effect on embryo production and cleavage proportion of early-lactation cows. The duration of WS supplementation in the prepartum period had no effect on milk yield and energy balance of the subsequent lactation, but it altered milk FA profile in early lactation by decreasing unsaturated FA content, notably when starting to supplement WS at 90 and 60 d from the expected calving date. Our results also showed that the duration of WS supplementation during the prepartum period does not improve oocyte quality in the subsequent lactation of cows.

Effects of chitosan and whole raw soybeans on ruminal fermentation and bacterial populations, and milk fatty acid profile in dairy cows

The objective of this study was to evaluate whether providing chitosan (CHI) to cows fed diets supplemented with whole raw soybeans (WRS) would affect the nutrient intake and digestibility, ruminal fermentation and bacterial populations, microbial protein synthesis, N utilization, blood metabolites, and milk yield and composition of dairy cows. Twenty-four multiparous Holstein cows (141 ± 37.1 d in milk, 38.8 ± 6.42 kg/d of milk yield; mean ± SD) were enrolled to a 4 × 4 Latin square design experiment with 23-d periods. Cows were blocked within Latin squares according to milk yield, days in milk, body weight, and rumen cannula (n = 8). A 2 × 2 factorial treatment arrangement was randomly assigned to cows within blocks. Treatments were composed of diets with 2 inclusion rates of WRS (0 or 14% diet dry matter) and 2 doses of CHI (0 or 4 g/kg of dry matter, Polymar Ciência e Nutrição, Fortaleza, Brazil). In general, CHI+WRS negatively affected nutrient intake and digestibility of cows, decreasing milk yield and solids production. The CHI increased ruminal pH and decreased acetate to propionate ratio, and WRS reduced NH3-N concentration and acetate to propionate in the rumen. The CHI reduced the relative bacterial population of Butyrivibrio group, whereas WRS decreased the relative bacterial population of Butyrivibrio group, and Fibrobacter succinogenes, and increased the relative bacterial population of Streptococcus bovis. No interaction effects between CHI and WRS were observed on ruminal fermentation and bacterial populations. The CHI+WRS decreased N intake, microbial N synthesis, and N secreted in milk of cows. The WRS increased N excreted in feces and consequently decreased the N excreted in urine. The CHI had no effects on blood metabolites, but WRS decreased blood concentrations of glucose and increased blood cholesterol concentration. The CHI and WRS improved efficiency of milk yield of cows in terms of fat-corrected milk, energy-corrected milk, and net energy of lactation. The CHI increased milk concentration [g/100 g of fatty acids (FA)] of 18:1 trans-11, 18:2 cis-9,cis-12, 18:3 cis-9,cis-12,cis-15, 18:1 cis-9,trans-11, total monounsaturated FA, and total polyunsaturated FA. The WRS increased total monounsaturated FA, polyunsaturated FA, and 18:0 to unsaturated FA ratio in milk of cows. Evidence indicates that supplementing diets with unsaturated fat sources along with CHI negatively affects nutrient intake and digestibility of cows, resulting in less milk production. Diet supplementation with CHI or WRS can improve feed efficiency and increases unsaturated FA concentration in milk of dairy cows.

Effect of organic sources of minerals on fat-corrected milk yield of dairy cows in confinement

This study evaluated the effects of organic and inorganic sources of minerals in diets for mid-lactation dairy cows on milk yield and composition, intake and total apparent digestibility of dry matter and nutrients, blood parameters, microbial protein synthesis, and energy and protein balances. Twenty Holstein cows averaging 146.83±67.34 days in milk and weighing 625.30±80.37 kg were used. The experimental design was a crossover. Diets were composed of corn silage (50%), ground grain corn, and soybean meal, differing with regard to the sources of trace minerals, plus an organic and inorganic mix. The organic mineral source increased milk fat and fat-corrected milk yield without changing milk yield, intake, or total apparent digestibility. Blood parameters, microbial protein synthesis, and energy and protein balances were not affected by the sources of minerals. Organic sources of minerals improve milk fat yield without affecting other parameters.