Effects of lipid and starch supplementation as water intake mitigation techniques on performance and efficiency of nursing Holstein calves.

Exploring alternative supplementation sources capable of maximizing feed and water efficiency in nursing Holstein calves is often ignored. The goals herein involve investigating the effects of two isoenergetic supplements on a nonmedicated milk replacer diet on total water intake, milk water intake, fresh water intake, feed intake parameters, and performance of Holstein nursing bull calves. Twenty-three animals (body weight [BW] = 94.67 ± 12.07 kg, age = 67 days old) were randomly assigned to one of three treatments for 68 days: control (CON; ad libitum milk replacer, n = 7), carbohydrate supplement (CHO; corn starch on top of ad libitum milk replacer-based diet, n = 8), or lipid supplement (FAT; menhaden fish oil on top of ad libitum milk replacer-based diet, n = 8). The isoenergetic supplementation consisted of 3% menhaden fish oil addition on DM basis for FAT. This was matched energetically with corn starch for the CHO group resulting in a 7% composition in DM basis. All animals were provided free access to mineral mix and 120 g daily dried microbrewer's spent grains (BG). Data were analyzed with the GLMMIX procedure of SAS in a completely randomized design with the diets as a fixed effect. Dry matter intake (DMI) adjusted by average daily gain (ADG; DMI/ADG) resulted in significantly lower values for supplemented groups with CON = 2.48, CHO = 2.38, and FAT = 2.27 kg/kg (ADG) (P = 0.033). Energy intake values were lower for CON when analyzing metabolizable energy intake (P < 0.0001), net energy intake for maintenance (P < 0.0001), and net energy intake for gain (P < 0.0001), followed by CHO, and then FAT. Total water intake (P < 0.0001), milk water intake (P < 0.0001), and fresh water intake (P < 0.0001) all resulted in CHO consuming 0.5 L or less water than the other two treatments. Energy requirements as digestible energy (P < 0.0001), metabolizable energy (P < 0.0001), net energy for maintenance (P < 0.0001), and net energy for gain (P < 0.0001) were lower for CHO, followed by CON, and then FAT having the highest requirements. Similar results were observed for residual feed (RFI; P = 0.006) and residual water intakes (RTWI; P = 0.902). Ultimately, no performance differences were detected with regards to BW (CON = 146.71, CHO = 146.25, and FAT = 150.48 kg; P > 0.1). These results indicate that lipid-based and starch-based supplementation can potentially increase feed efficiency and decrease voluntary water intake without adversely affecting performance.

Effect of quebracho condensed tannin extract on fecal gas flux in steers.

Naturally occurring gaseous by-products of ruminant production-carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2 O)-can negatively affect the environment. Along with enteric fermentation, manure on pasture is among the most significant contributors to non-CO2 emissions. Condensed tannins, a group of naturally occurring phenolic compounds, can alter the route of nutrient excretion and interact with microbes, suggesting they are a plausible feed additive for reducing excreta gas emissions. We evaluated how quebracho (Schinopsis balansae) tannin extract fed at 0, 15, 30, and 45 g kg-1 of dry matter (DM) within a roughage-based diet affected fecal gas emissions at multiple locations (College Station and Stephenville, TX) during two periods corresponding to winter and spring. During both periods, CO2 , CH4 , and N2 O fluxes were determined using the vented-static chamber methodology over 39 d, and cumulative emissions were calculated. A random coefficients model with animal nested within dietary treatment and period as the random factor was analyzed by location due to the presence of collinearity with soil parameters within periods. Daily CO2 flux was influenced by soil moisture and temperature (r = .34; P < .01), whereas CH4 and N2 O were associated with soil moisture. Cumulative gas production confirmed a dietary effect for CO2 and gross CO2 equivalent at the College Station site (P ≤ .001), demonstrating a linear reduction as quebracho inclusion increased. Variance partitioning indicated that dietary treatment and seasonal period likely influenced animal digestive and metabolic parameters. Within specific environments, quebracho supplementation may assist in reducing fecal gas emissions.