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Effects of monensin withdrawal and cattle subspecies on the utilization of bermudagrass hay (14.3% CP, 72.3% NDF, and 36.9% ADF) were evaluated using ruminally cannulated steers (5 Bos taurus indicus[BI] and 5 Bos taurus taurus[BT]). Subspecies were concurrently subjected to a 2-period, 2-treatment crossover design. Treatments consisted of either 0 mg·steer−1·d−1 monensin with no previous monensin feeding (CON) or withdrawal from 200 mg·steer−1·d−1 monensin (MON) fed individually in 0.91 kg dried distillers' grains with solubles for 42 d. Withdrawal was evaluated for a 28-d period. Ruminal fluid was collected 2 h after feeding on d 0, 1, 4, 7, 14, and 21 after withdrawal for determination of pH, VFA, ruminal NH3–N (RAN), rate of NH3production, and CH4production rate. Hay, ort, and fecal grab samples were collected d 23 through 28 after withdrawal for determination of intake and digestion. No subspecies × monensin, subspecies × day, or subspecies × monensin × day interactions were observed (P≥ 0.11). An effect of day after monensin withdrawal was observed (P< 0.01) for total VFA concentration, with an increase following withdrawal followed by a decrease and then stabilization. Monensin × day after monensin withdrawal interactions (P≤ 0.01) were observed for the acetate:propionate (A:P) ratio and molar percent of acetate and propionate. There was a decrease in molar percent of propionate between d 1 and 4 from 19.1 to 18.0; however, it remained greater (P≤ 0.10) for MON than CON through d 7. Withdrawal increased molar percent of acetate from 68.3 to 69.8 between d 0 and 4 for MON steers. The A:P ratio was less (P≤ 0.01) on d 0 for MON than for CON (3.4 vs. 4.0), but by d 4, it increased to 3.8 and was not different (P= 0.14) from CON. By d 14, no differences (P≥ 0.88) remained for acetate, propionate, or the A:P ratio. After monensin withdrawal, monensin reduced (P< 0.01) RAN by 12.3% (2.09 vs. 1.83 mMfor CON and MON, respectively). Monensin withdrawal and cattle subspecies had no effect (P≥ 0.23) on rate of NH3production or CH4production rate. Monensin withdrawal had no effect (P≥ 0.45) on intake or digestibility parameters. Greater forage OM intake (P= 0.09; 21.2 vs. 19.2 g/kg BW) and OM digestibility (P< 0.01; 72.4 vs. 63.0%) resulted in greater (P< 0.01) total digestible OM intake (16.8 vs. 13.2 g/kg BW) in BT steers than in BI steers. These results suggest that BT steers are better able to utilize bermudagrass hay than BI steers. Upon monensin withdrawal, steers previously fed monensin continue to have a reduced A:P ratio for at least 7 d.

Effects of monensin inclusion and cattle subspecies on utilization of bermudagrass hay (13.7% CP, 77.3% NDF, and 38.8% ADF) were evaluated using ruminally cannulated steers (5 Bos taurus indicus[BI] and 5 Bos taurus taurus[BT]; 398 kg BW). Subspecies were concurrently subjected to a 2-period, 2-treatment crossover design. Treatments were 0 (CON) or 200 mg·steer−1·d−1monensin (MON) in 0.91 kg dried distillers' grains with solubles. Periods were 70 d in length: 20 d of adaptation, 22 d of sample collection, and 28 d for withdrawal of treatment. Steers were group housed during adaptation and moved to individual covered pens for sampling. Hay, ort, and fecal grab samples were collected d 21 through 25 for determination of intake and digestion. Ruminal fluid was collected with a suction strainer 0, 2, 4, 8, and 12 h after feeding on d 42 for pH, VFA, and ruminal NH3–N (RAN) analysis. Additionally, at h 2, ruminal fluid and contents were collected for determination of rate of NH3production and CH4production rate. No subspecies × monensin interactions were observed (P≥ 0.12). Monensin had no effect (P≥ 0.16) on intake or digestibility parameters. No subspecies effect (P≥ 0.11) was observed for forage OM intake, total OM intake, or OM digestion. Total digestible OM intake tended to be greater (P= 0.06) for BT steers than for BI steers (14.0 vs. 12.2 g/kg BW). There was an effect of hour after feeding (P≤ 0.01) on pH, total VFA, acetate:propionate ratio, and molar percent acetate and propionate. Total VFA concentration was greater (P= 0.01) in CON steers than in MON steers (66.5 vs. 62.0 mM). Monensin decreased molar percent acetate (P= 0.02) from 72.5 to 71.2% and increased molar percent propionate (P< 0.01) from 16.9 to 18.7%, resulting in a reduced (P< 0.01) acetate:propionate ratio (from 4.34 to 3.85). Although not significantly (P= 0.19), monensin numerically reduced the CH4production rate by 15.8%. Greater (P= 0.07) CH4production rate tended to be observed in BI steers than in BT steers (21.4 vs. 16.6 μmol CH4·mL−1·h−1, respectively). Monensin had no effect (P≥ 0.32) on pH, RAN, or rate of NH3production. A subspecies × hour after feeding interaction was observed for RAN, with BT having greater RAN at h 0 and 4, whereas BI had greater RAN at h 2, 8, and 12. Overall, monensin decreased the acetate:propionate ratio and total VFA concentration but had no effect on forage utilization. Bos taurus indicussteers consumed less digestible OM and had a greater CH4production rate compared with BT steers, suggesting BT were better able to utilize the available forage resource than BI.

AbstractBacterial and fungal communities in indigenous tussock grassland soils were studied at four locations, Mt Benger and Deep Stream (Otago), Cass (Canterbury) and Tukino (central North Island). Soil samples collected from inter‐tussock and tussock areas were used to enumerate total culturable bacteria (colony forming units (CFU)) as well as a number of specific groups of bacteria, fungal types and diversity, and soil microbial functional diversity. Soil microbial biomass carbon (C) and nitrogen (N) as well as extractable C and N were also determined. Fungal populations were lowest at Mt Benger while fluorescent Pseudomonaswas lowest at Cass. In these indigenous soils, bacterial CFU were c. 30 times lower and fungal populations c. 10 times greater than in developed New Zealand pastoral soils. CFU of bacteria in complex media (r‐strategists) were similar in magnitude to bacteria growing on weak CA medium (K‐strategists). The microbial biomass C in indigenous grassland soils were also significantly greater than that found in developed pastoral soils, possibly due to dominance of fungi in indigenous soils. Microbial C and N were lower in Cass and Tukino sites compared to Mt Benger and Deep Stream sites. Microbial nitrogen was also significantly greater (P< 0.001) in inter‐tussock than under tussock samples. The functional diversity of soil microbes, was significantly greater (P< 0.01) in inter‐tussock samples compared to tussock samples at all sites except Mt Benger. The total microbial activity, as measured by the colour development in Biolog plates (Average Well Colour Development (AWCD)), was low in Cass soil compared to others. Eighty‐three types of fungi belonging to 30 genera were recovered from the four sites. The diversity of fungi found in Otago sites was greater than in the other two sites (P <0.001). Fusariumspp. that are often common in pastoral soils were conspicuous by their rarity in indigenous soils.

AbstractThis contribution introduces a short series of papers on biodiversity of indigenous tussock grassland at four sites in New Zealand. A survey of invertebrates of tussock grassland sites was carried out in summer of 3 successive years, 2001–03. The sites included two in Otago in snow tussock grassland at Deep Stream and Mt Benger, a site at Cass in inland Canterbury, and one at Tukino in the central North Island. Sampling was carried out by taking turf samples from each site, and extracting the invertebrates with heat extractors. The invertebrates were divided into 30 major groups. This quantitative sampling method allowed the densities of invertebrate groups to be calculated. Total macro‐invertebrate density for all sites ranged between c. 1600 and 5600 m–2. Total invertebrate abundance was highest at the central North Island site, but this was very much dominated by Formicidae. Across all sites, Formicidae, Coleoptera, and Pseudococcidae were consistently the most abundant groups represented.

AbstractSoil samples were taken from around the base of tussock plants and paired areas of inter‐tussock vegetation at four native tussock grassland sites across New Zealand, in three consecutive summers. Seventy nematode taxa were identified with the plant associated nematode trophic group being the most abundant at three of the four sites. Of the plant parasitic nematodes, Criconema, Pratylenchus, and Helicotylenchusspp. were found at all sites, with Hemicycliophora, Longidorus, a putative Punctodera, and Rotylenchusfound at only one site each. The observation of mermithid nematodes at three of the four sites, coupled with absence of insect parasitic Steinernemaor Heterorhabditissp. from microscopic observations and soil baiting suggests that the insect parasitism niche is occupied largely by mermithids in the tussock grassland habitats studied. A range of community indices were calculated, with Shannon‐Weiner (2.10–2.39), Simpson dominance (0.129–0.205), Maturity Index (2.67–2.92), and Structure Index (67.7–87.5) being significantly different among sites. Total nematode abundance was significantly greater beneath tussock than inter‐tussock vegetation, but the number of nematode taxa and species richness were significantly greater from inter‐tussock samples. This suggests that tussocks may provide a more productive habitat but that the increased diversity of the vegetation in inter‐tussock areas is reflected in some measures of nematode diversity. Comparisons are made and discussed with other studies of native grassland nematodes in New Zealand and worldwide.

Helicotylenchus spitsbergensis Loof, 1971 is recorded in Chionochloa rigida (snow tussock) grassland soil from Otago, New Zealand. Morphometrics and descriptions of male and female specimens are given. An updated key to the Helicotylenchus species from New Zealand is also presented.

Research on the role of predatory mites as biological control agents for the lucerne flea, Sminthurus viridis, is reviewed and their potential use in New Zealand pastoral systems is discussed. Three predatory mites are considered, the pasture snout mite (Bdellodes lapidaria), the spiny snout mite (Neomolgus capillatus), and the French anystis mite (Anystis wallacei). Of these, only B. lapidaria is already present in New Zealand but climate may limit its effectiveness in areas of New Zealand north and west of Palmerston North. Both N. capillatus and A. wallacei are established in Australia but data currently available suggest that the importation of only N. capillatus should be considered, subject to quarantine requirements. N. capillatus has been a particularly effective predator of lucerne flea in areas of Tasmania with a similar climate to the northern and western areas of the North Island. A survey of potential mite predators that already exist in New Zealand pastures should also be undertaken.

The effect of monensin and protein on digestion and ruminal fermentation parameters in cows consuming low-quality forage (LQF; 4.1% CP chopped bluestem hay) was evaluated. Four ruminally cannulated cows (637 ± 24 kg BW) were used in a 4 × 4 Latin square design (20 d periods). Treatments were arranged as a 2 × 2 factorial: the first factor was monensin (0 or 200 mg·cow−1·d−1) and the second factor was protein (0 or 0.64 kg·cow−1·d−1CP provided as cottonseed meal). A carrier supplement (0.23 kg·cow−1·d−1) consisting of ground hay, cracked corn, molasses, salt, dicalcium phosphate, and a commercial mineral premix was provided to all animals and allowed for inclusion of monensin. Animals were housed and individually fed at 0600 h daily. To prevent carryover effects from previous monensin feeding, 14 d were required before sampling. However, to obtain the optimal response from monensin, only 10 d were needed for treatment adaptation. Therefore, during d 1 through 4 of each period, animals were fed LQF with no treatment. Day 5 through 14 allowed for treatment adaptation and d 15 to 20 was used for sample collection. Digestion measurements were taken d 15 through 19. Rumen fluid was collected h 0, 2, 4, 8, 12, 16, and 20 on d 20 for VFA analyses. Data were analyzed using the MIXED procedure in SAS 9.3 (SAS Inst. Inc., Cary, NC) with terms in the model including protein, monensin, and their interaction, with animal and period included as random effects. There was no protein × monensin interaction (P≥ 0.30) or effect of monensin (P≥ 0.37) on any digestion parameter measured. Protein increased OM digestibility (P= 0.01), total digestible OM intake (P< 0.01), and total digestible NDF intake (P< 0.01) by 10.7, 112, and 71.2%, respectively. Protein had no effect on NDF digestibility (P= 0.13). A protein × monensin interaction (P= 0.17) or effect of monensin (P= 0.15) was not observed for total VFA concentration. Protein increased (P< 0.01) total VFA concentration by 20.0%. A protein × monensin interaction was observed for the acetate:propionate ratio (P= 0.05), with protein reducing the ratio when no monensin was present and increasing the ratio when monensin was present. No protein × monensin interaction (P= 0.51) was observed for acetate or propionate concentration. Protein had no effect on acetate (P= 0.11) or propionate (P= 0.67). Monensin increased (P= 0.03) propionate concentration by 8.6% but had no effect (P= 0.41) on acetate. Results suggest that protein increases digestibility when feeding a LQF but that no added benefit is observed with monensin inclusion.

There is an increased demand for motivated students, especially those from underrepresented populations, to enter postsecondary STEM fields. Animal science is an innovative curriculum that can motivate students and spark interest in STEM careers. The need for general scientific literacy is continually increasing. To recruit students to such programs, we must understand what motivates them. The purpose of this study was to determine how the post-secondary agriculture students in an introductory course conceptualized their motivation to learn science skills in animal science. A descriptive-correlational research design was utilized with a modified version of the Science Motivation Questionnaire II (SMQ II) used as the survey instrument.The sample population for this study was taken from an introduction to animal science class at a southern Hispanic Serving Institution. After IRB approval, students were asked to complete the SMQ II. An advantage of this questionnaire is that it does not distinguish between science subjects, but focuses on a general motivation to learn science. It has been emphasized by previous research that the instrument can easily be used in all of science. For this study, we replaced the term “science” with “animal science.”The 25-question instrument included the following five-item scales: intrinsic motivation, self-determination, self-efficacy, career motivation,and grade motivation.Students respond to each item on a Likert-type rating scale: never (1) to always (5). The reliability of the individual scales assessed by Cronbach’s alphas for the modified instrument was: career motivation (d= 0.90), intrinsic motivation (d= 0.89), self-determination (d= 0.88), self-efficacy (d= 0.56), and grade motivation (d= 0.84). The raw scores should be interpreted carefully, as the scales are ordinal. Collected data was entered and analyzed using SPSS version 19 on measures of central tendency and correlations where appropriate.Science Motivation Construct Scores (n = 16)ConstructMSDCareer Motivation4.630.61Intrinsic Motivation4.440.72Grade Motivation4.430.73Self-Efficacy4.210.70Self-Determination4.210.77The highest individual science motivation scores for the specific prompts were: Understanding animal science will benefit me in my future career (m = 4.75, SD = .58), Getting a good animal science grade is important to me (m = 4.69, SD = .48), Knowing animal science will give me a career advantage (m = 4.63, SD = .62). The results of this study show the desire students have in knowing a degree will help them in their future career path.

The effect of dietary sulfur on digestibility of feedstuffs is not well defined. The primary objective of this study was to evaluate the effect of dietary sulfur on in vitro true digestibility (IVTD) of various feedstuffs. A secondary objective was to determine the effect of sulfur-treated rumen fluid on IVTD of various feedstuffs. Treatments consisted of 0 (CON) or 0.3% (SUL) sulfur mixed into the ration of 8 Dorper wethers (29.87 ± 0.52 kg BW) consuming a commercial growing ration (Purina Honor Show Chow Show lamb Grower 15% DX Medicated feed) with chopped coastal hay mixed at 90:10%. Wethers were individually housed for the duration of the 56-d trial. Feedstuffs were selected to represent a variety in nutrient quality and included 4 roughages (wheat straw, bluestem hay, coastal hay, and alfalfa hay) and 3 commercial feedlot rations (starter, intermediate, and finisher diets). Ground feedstuff samples containing CON or SUL treatments were weighed into F57 nylon filter bags in quadruplicate. Sheep were slaughtered 56 d after commencing sulfur inclusion. Gastrointestinal tracts were collected during slaughter to allow for rumen fluid collection. Rumen fluid was processed and IVTD protocol was performed in accordance with ANKOM (2005) using an ANKOM DaisyIIIncubator. Data were analyzed using the MIXED procedure of SAS 9.3 (SAS Inst. Inc., Cary, NC). An interaction between treatment and feedstuff was not observed (P≥ 0.64). A main effect of treatment was not observed (P≥ 0.22). A main effect of feedstuff was observed (P< 0.01) with starter feedlot ration having the greatest IVTD and wheat straw having the lowest. Results suggest that dietary sulfur does not impact IVTD of feedstuffs, but great diversity exists amongst different types of diets.

The effect of including monensin in a protein supplement fed to cattle consuming low-quality forage is not well defined. The objective of this study was to evaluate the effects of monensin and protein supplementation on in situdisappearance kinetics of low-quality forage (LQF; 4.1% CP). Four cannulated cows were used in a 4 × 4 Latin Square design with treatments arranged as a 2 × 2 factorial: the first factor was monensin (0 or 200 mg·hd−1·d−1), and the second factor was protein supplement (0 or 0.64 kg·hd−1·d−1CP provided as cottonseed meal; CSM). A premix (0.23 kg·hd−1·d−1) consisting of ground hay, cracked corn, molasses, salt, dicalcium phosphate, and a commercial mineral mix, was provided to all animals and allowed for monensin inclusion. Animals were individually housed and fed at 0600 h daily. Prior to sampling, 14 d were required to prevent carryover effects from previous monensin feeding. However, only 10 days of treatment adaptation was required for optimal monensin response. Thus, d 1 to 4 of each period, all animals were provided LQF with no treatment. Day 5 to 14 served as treatment adaptation, and sampling occurred d 15 to 20. Samples of LQF were weighed into 10- by 20-cm polyester bags in replicates of six for each hour. On d 15, bags were placed into the ventral area of rumen and replicates removed after 0, 4, 8, 16, 24, 48, 72, and 96 h of incubation. Upon removal from the rumen, bags were placed in ice water, rinsed, and then frozen until final bag removal. Bags were washed in a commercial washing machine and then dried at 55°C to a constant weight. Dried residues were analyzed for DM. In situ rumen DM degradation data were fitted to the first-order exponential model with discrete lag using the iterative Marquardt method and NLIN procedure of SAS 9.3. There was no interaction (P≥ 0.16) between protein and monensin for any DM disappearance parameters measured. Protein had a tendency (P= 0.07) to reduce potentially degradable DM (from 58.60 to 50.42%) likely due to the increased (P≤ 0.01) rate of DM degradation (from 1.87 to 4.76%/h) that it caused. Monensin had no effect (P= 0.12) on potentially degradable DM but increased (P= 0.03) rate of degradation from 3.06 to 3.57%/h. Protein or monensin supplementation had no effect on lag time or residue (P≥ 0.11). It is likely that the increased rate of degradation caused by protein and monensin will allow increased intake of LQF, thus improving its use in production operations.

It is believed that sulfur may reduce palatability of lamb, but the resulting effect on digestibility is not clear. The primary objective of this study was to evaluate the effect of dietary sulfur on in vitro true digestibility (IVTD) of a commercial ration fed to 8 Dorper wethers (29.87 ± 0.52 kg BW). A secondary objective was to determine the effect of sulfur-treated rumen fluid on digestibility of diets containing 2 levels of sulfur. Treatments consisted of 0 (CON) or 0.3% (SUL) sulfur mixed into the ration of 8 Dorper wethers (29.87 ± 0.52 kg BW) consuming a commercial growing ration (Purina Honor Show Chow Show lamb Grower 15% DX Medicated feed) with chopped coastal hay mixed at 90:10%. Wethers were individually housed for the duration of the 56-d trial. Ground feedstuff samples containing CON or SUL treatments were weighed into F57 nylon filter bags in quadruplicate. Sheep were slaughtered 56 d after commencing sulfur inclusion. Gastrointestinal tracts were collected during slaughter to allow for rumen fluid collection. Rumen fluid was processed and IVTD protocol performed in accordance with ANKOM (2005) using an ANKOM DaisyIIIncubator. Data were analyzed using the MIXED procedure of SAS 9.3 (SAS Inst. Inc., Cary, NC). Sulfur had no effect (P= 0.16; 85.20 vs. 83.00% IVTD, respectively) on IVTD of CON vs. SUL feedstuffs. Rumen fluid from SUL sheep did not differ in its ability to degrade feedstuffs when compared with rumen fluid from CON sheep (P= 0.81; 84.37 vs. 83.83% IVTD for CON vs. SUL rumen fluid, respectively). Results suggest that dietary sulfur could be altered to benefit lamb palatability without affecting digestibility.

The effect of monensin (Rumensin 90) and protein supplementation on intake, digestion, and ruminal fermentation parameters on cows consuming low-quality forage (LQF; 4.1% CP chopped bluestem hay) was evaluated. Four ruminally cannulated cows (637 ± 24 kg BW) were used in a 4 × 4 Latin square design (20-d periods). Treatments were arranged as a 2 × 2 factorial: the first factor was monensin (0 or 200 mg·cow−1·d−1) and the second factor was protein supplement (0 or 0.64 kg·cow−1·d−1CP provided as cottonseed meal). A premix (0.23 kg∙cow−1∙d−1) consisting of ground hay, cracked corn, molasses, salt, dicalcium phosphate, and a commercial mineral premix was provided to all animals and allowed for inclusion of monensin. Animals were housed and individually fed at 0600 h daily. To prevent carryover effects from previous monensin feeding, 14 d were required before sampling. However, to obtain an optimal response from monensin, only 10 d were needed for treatment adaptation. Therefore, during d 1 to 4 of each period, all animals were fed LQF with no treatment. Day 5 through 14 allowed for treatment adaptation and Day 15 through 20 for sample collection. Intake measurements were taken d 15 to 19. Rumen fluid was collected h 0, 2, 4, 8, 12, 16, and 20 on d 20 to determine pH. Data were analyzed using the MIXED procedure in SAS 9.3 (SAS Inst. Inc., Cary, NC) with terms in the model including protein, monensin, and their interaction, with animal and period included as random effects. No protein × monensin interaction (P= 0.37) or effect of monensin (P= 0.32) was observed for any measure of intake. An effect of protein was observed for total OM intake (TOMI; P< 0.01), forage OM intake (FOMI; P< 0.01), total NDF intake (TNDFI; P< 0.01), and forage NDF intake (FNDFI; P< 0.01). Protein increased TOMI by 88.4%, FOMI by 86.8%, TNDFI by 61.6%, and FNDFI by 55.2%. A protein × monensin × hour interaction was observed (P= 0.005) for pH. This interaction was likely caused by the interaction of protein with hour after feeding and the interaction of protein and monensin at 0 h after feeding. Results suggest that adding monensin to a protein supplement for cattle consuming LQF will not provide an added improvement on intake compared with protein alone.

Drought and elevated land prices challenge the US cow-calf sector to meet increasing global beef demands via conventional, extensive methods. An alternative cow feeding and calving approach, accomplished in a controlled environment (i.e. drylot) was investigated using sixty, multiparous, late-gestation beef cows (461.5 kg initial BW). Cows (N = 60) were blocked by BW and individually fed one of four treatments (70, 85, 100, and 115% of NRC-predicted maintenance energy) in Calan gates for an average of 71 d before calving. Diets consisted of 2.00 kg of wheat straw (2.5% CP; 79% NDF) and four levels of a mixture of corn (45%), distiller's grain (42%) and premix (13%) fed at 2.70, 3.42, 4.12, and 4.85 kg/d to correspond with the 70, 85, 100, and 115% treatments. Following calving, pairs were managed as a group on pasture. Digestible energy intake increased linearly (11.84, 13.55, 15.53 and 17.71 Mcal/d for 70, 85, 100, and 115%; P< 0.01) per design; ME intake responded similarly (9.71, 11.11, 12.74 and 14.53 Mcal/d). No treatment differences (P> 0.05) in digestibility were observed; DM digestibility averaged 62%. Cow retained energy over the duration of the study increased linearly (P< 0.01) from 46.6 Mcal for 70% to 50.7, 106.3, and 123.8 Mcal for 85, 100, and 115%. Body weight gain increased linearly (P< 0.01) from 0.7 kg for 70% to 3.6, 17.7, and 24.2 kg for 85, 100, and 115%. Calf birth weight increased linearly (P= 0.01) from 32.5 kg for 70% to 35.5, 35.2, and 36.8 kg for 85, 100, and 115%. There were no differences (P> 0.05) in cow or calf body weights among treatments at 60, 90, 120 or 160 days post parturition. Brix (%) values of cow colostrum at parturition did not differ (P> 0.05). Immunoglobulin G levels in calf serum collected 24 h after birth did not differ (P> 0.05). No differences (P> 0.05) in postpartum interval were observed. Production goals of the cow-calf sector can be successfully met by limit feeding late-gestation beef cows in a drylot setting at levels at least 70% of NRC-predicted energy requirements for maintenance.