No abstract

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 non-medicated 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.

No abstract

Opuntia ficus-indica is highly regarded as an emergency feed for livestock during drought and as a mainstay for the wildlife population in temperate semi-arid and arid parts of the United States. The goal of this study was to assess the effects of replacing alfalfa and orchard grass with different levels of prickly pear on digestion and fermentation patterns. Three forages were evaluated: alfalfa, orchard grass and prickly pear. In order to determine kinetics of digestion, gas volumes were measured after incubation periods of 0, 3, 6, 12, and 24 h. Samples were run in triplicate with 2 blanks for a total of three periods. Data on gas production were fitted to the equation by Ørskov and McDonald (1979) using SAS software 9.4 (P ≤ 0.05; SAS Inst. Inc., Cary, NC) program. The gas volume observed from the soluble fraction ‘a’ and ‘b’ were similar (P > 0.05) for prickly pear amongst all treatments; no difference was observed between alfalfa and cactus. The rate of gas production ‘c’ was higher in cactus (16.5%, h-1) than alfalfa and orchard grass (11.5%, h-1 and 7.7%, h-1, respectively). The extent ‘a +b’ of gas volumes revealed no difference among the test forages. Prickly pear showed a faster rate of degradation compared to alfalfa and orchard grass. A rapid rate of digestion means a faster passage of the material through the digestive tract. Thus, the higher values obtained for the ‘c’ and similar ‘a + b’ parameters in prickly pear compared to alfalfa or orchard grass, may signal it as a good potential alternative feed in arid and semi-arid areas.

Water footprint (WF) of livestock can be manipulated to improve water use efficiency. The dynamics of water use by Holstein nursing bull calves (HBC) is not very well stablished. The physiological and anatomical status of HBC permits for precise-diet manipulation aiming to decreasing voluntary water intake (WI); however, WI mitigation raises concerns about potential adverse effects on hydration and health. The goals herein involve investigation of the effects of two isoenergetic supplements top-dressed on ad libitum non-medicated milk-replacer (MR) on health, hydration, and WF of HBC. A total of 23 HBC weighing 94.67 ± 12.07 kg, 2 months old, were distributed in a completely randomized design receiving one of three diets for 67 days: control (CON; n = 7) received MR only, the lipid (FAT; n = 8) received MR supplemented with fish oil (3%), and the carbohydrate (CHO; n = 8) received corn starch (7%). All animals were offered mineral mix and water ad libitum, and 120 g daily dried brewer’s spent grains. Data were analyzed with the GLMMIX procedure of SAS 9.4 with diets as fixed effect. The WF was significantly decreased for the CHO group (P < 0.01). When WF values were adjusted by cold carcass weight (CCW), the CHO and FAT groups displayed a 100 L decrease in WF values compared to the CON. Though statistically significant differences were observed for Neutrophil count, lymphocyte count, and their ratio (NLR, as well as for total protein and fecal fluidity score (P < 0.05), the observed ranges were within healthy thresholds for HBC. Skin hydration was assessed through use of a skin moisture meter which resulted in the CHO group having significantly higher skin capacitance of 5.30 compared to CON = 3.76, and FAT= 3.99. These results evidence the possibility of increasing water use efficiency with precision diet formulation without adverse health and hydration effects.