Supplementation of prepartum dairy cows with ß-carotene.

The prepartum supplementation of dairy cows with ß-carotene was evaluated. Cows were blocked by parity and expected calving date and assigned to a treatment: ß-carotene (1.2 g/cow per d) or control (no supplementation). The same total mixed ration batch was offered to all cows, and ß-carotene was top dressed to individual cows once per day. The data set contained 283 Holsteins that received a treatment for >14 d (29.1±6.9 d). Frequency distributions were analyzed with the GENMOD procedure of SAS using logistic regression for binomial data. Continuous variables were analyzed with the MIXED procedure of SAS. Within parity, nonparametric estimates of the survivor function for reproductive variables were computed using the product-limit method of the Kaplan-Meier method with the LIFETEST procedure of SAS. Plasma ß-carotene concentration before supplementation was similar between supplemented and nonsupplemented cows (2.99µg/mL) and peaked at 3.26±0.175µg/mL on d -15±2.4 precalving for supplemented cows (2.62±0.168µg/mL for control). Colostrum density, milk yield, and milk composition were similar between treatments. ß-Carotene tended to increase milk protein content from 2.90 to 2.96% and to decrease the proportion of primiparous cows with a milk fat to protein ratio >1.5 from 22.6 to 6.4%. The proportion of primiparous and multiparous cows with difficult calving, metritis, progesterone >1 ng/mL at 21 d and at 42 d in lactation, % conception at first service, and % pregnancy at 90 and 150 d in lactation were similar between treatments. A trend for decreased incidence of somatic cell count >200,000 cells/mL was present in multiparous cows supplemented with ß-carotene (38.9% vs. 28.1%). ß-Carotene was associated with a reduction in the proportion of multiparous cows with retained placenta 12 h postpartum from 29.9 to 21.7%; time of placenta release was 392 min (340 to 440) for ß-carotene and 490 min (395 to 540) for control (median and 95% confidence interval). For primiparous cows, placenta release was not affected by ß-carotene (incidence was 15.4%). The intervals from calving to first estrus, to first service, and to conception were not affected by ß-carotene supplementation in either parity. However, independent of treatment, cows with improved reproductive efficiency had increased postpartum ß-carotene concentration in plasma. The prepartum supplementation of ß-carotene increased plasma concentration around calving. No response in milk yield or reproductive performance was detected. Beta-carotene supplementation was associated with a lower incidence of retained placenta in multiparous cows.

Response of lactating cows to live yeast supplementation during summer.

Dairy cows experiencing heat stress have reduced intake and increased reliance on glucose, making feeding strategies capable of improving diet digestibility plausible for improving postrumen nutrient flow and performance. The effect of yeast on digestion and performance of lactating cows during the warm summer months of southeastern Brazil was evaluated. Cows were individually fed in tie stalls and temperature-humidity index was above 68 during 75.6% of the experiment. Twenty-eight Holstein cows (207±87 d in milk) received a standard diet for 14 d and then a treatment for 70 d, in a covariate-adjusted, randomized block design with repeated measures over time. Treatments were yeast (Saccharomyces cerevisiae) or control. Yeast was top dressed to the diet in the morning, equivalent to 25×10(10) cfu of live cells and 5×10(10) cfu of dead cells. The diet contained corn silage (37.7%), Tifton silage (7.1%), raw soybeans (4.1%), soybean meal (16.5%), finely ground corn (20.7%), and citrus pulp (11.9%). Yeast increased milk (26.7 vs. 25.4 kg/d) and solids yield (3.06 vs. 2.92 kg/d), especially lactose. Response in milk yield was consistent over time and started at d 5. The daily intake of digestible OM, total-tract digestibility of nutrients, urinary allantoin excretion, chewing pattern throughout the day, and dry matter intake did not respond to yeast. A trend was observed for increased plasma glucose with yeast (62.9 vs. 57.3mg/dL), lowered respiratory frequency (48 vs. 56 breaths/min), and increased plasma niacin content (1.31 vs. 1.22 µg/mL), though cows had similar rectal temperature. Ruminal lactate and butyrate as proportions of ruminal organic acids were reduced by yeast, but no effects on other organic acids, ruminal pH, or protozoa content were detected. Plasma urea N over 24h was increased by yeast. On d 72 to 74, citrus pulp was abruptly replaced with finely ground corn to induce acidosis. The increased load of starch increased dry matter intake between 0700 and 1300 h, jugular blood partial pressure of CO2, HCO3-, and base excess, and decreased blood pH for both treatments. The yeast treatment had a higher blood pH compared with the control, 7.34, and 7.31, respectively. Yeast supplementation improved lactation performance of dairy cows under heat stress. Improvement in lactation performance apparently involved the regulation of body homeothermia, rather than improved digestibility.

Mortadella sausage manufactured with Caiman yacare (Caiman crocodilus yacare) meat, pork backfat, and soybean oil.

Mortadellas manufactured using Caiman yacare meat (70%) and pork fat (30%) were reformulated by substituting pork fat with increasing amounts of soybean oil (25%, 50%, and 100%) and evaluated 7, 30, and 60 days post-manufacture. The substitutions resulted in an increase in fat content and in the percentage of polyunsaturated fatty acids (total PUFA; 18:2 n-6 and 18:3 n-3), and a reduction in saturated fatty acids (total SFA; 14:0 and 16:0). These alterations reduced (P<0.01) the indices of atherogenicity and thrombogenicity by 4- to 5-fold in the formulation with 100% soybean oil compared to the original formulation. The levels of TBARS obtained at day 7 were positively correlated (P<0.01) with 18:2 n-6 and 18:3 n-3 (r=0.83 and 0.84, respectively) and negatively correlated with 17:0 and 17:1 (r=-0.91 and -0.89, respectively). All formulations received favourable overall acceptability by the sensory panel.