Y. Tsukahara

Simple methods to estimate the maintenance feed requirement of small ruminants with different levels of feed restriction

ABSTRACT Ten Katahdin (KAT) sheep and 10 Spanish (SPA) goat wethers were used to develop a simple method to estimate dry matter intake (DMI) required for maintenance (DMIm) with feed restriction. Grass hay was fed in a 5-week maintenance phase, initially at 51 and 54 g/kg BW0.75 for KAT and SPA, respectively, and then varied by 0–5% every 2–3 days to maintain constant body weight (BW). Individual wether DMIm was the intercept of regressing DMI against BW change in 2- and 3-day periods of weeks 3 and 4. In the subsequent 8 week, wethers consumed hay at 70% or 55% of their maintenance DMIm. Restricted DMIm was average DMI in week 8 when no individual wether intercept of regressing BW against day differed from 0. Maintenance DMIm was not influenced by animal type (52.0 and 49.6 g/kg BW0.75 for KAT and SPA, respectively; SEM = 0.73). Animal type and restriction level tended (p = .084) to interact in restricted DMIm (34.1, 38.6, 30.7, and 39.0 g/kg BW0.75 for KAT-55%, KAT-70%, SPA-55%, and SPA-70%, respectively; SEM = 1.03), suggesting greater ability of Spanish to lessen energy use with appreciable feed restriction. Correlation coefficients of 0.89, −0.06, 0.96, and 0.85 (p = .041, .927, .009, and .066, respectively) between DMIm in the two phases for KAT-55, KAT-70, SPA-55, and SPA-70, respectively, suggest preference for the 55% level for evaluating resilience to feed restriction. In conclusion, frequent determinations of BW and DMI can be used to compare DMIm of individual animals with restricted feeding.

Effects of level of brackish water on feed intake, digestion, heat energy, and blood constituents of growing Boer and Spanish goat wethers.

Twenty Boer (6.1 mo old and 21.3 kg) and 20 Spanish (6.6 mo old and 19.7 kg) goat wethers were used to determine effects of brackish water on feed intake, digestion, heat energy, and blood constituents. Brackish water had 6,900 mg/L total dissolved salts, 1,885 mg/L Na, 75 mg/L Mg, 1,854 mg/L chloride, 2,478 mg/L sulfate, and 9 mg/L boron. Water treatments were 100% tap water (control), 100% of a brackish water source (100-BR), 33% control and 67% brackish water (67-BR), and 67% control and 33% brackish water (33-BR). Water and a moderate-quality grass hay (8.5% CP and 68% NDF) were offered free choice. The experiment consisted of 14 d of adaptation, 5 d for metabolizability measures, and 2 d for determining gas exchange and heat energy. There were no interactions ( > 0.05) between breed and water treatment. Water intake (931, 942, 949, and 886 g/d [SE 59.1] for the control, 33-BR, 67-BR, and 100-BR, respectively) and DM intake (525, 556, 571, and 527 g/d [SE 31.0] for the control, 33-BR, 67-BR, and 100-BR, respectively) were similar among treatments ( = 0.876 and = 0.667, respectively). Urinary water was greater for brackish water treatments than for the control ( = 0.003; 211, 317, 319, and 285 g/d [SE 25.6] for the control, 33-BR, 67-BR, and 100-BR, respectively) and fecal water content was similar among treatments ( = 0.530; 247, 251, 276, and 257 g/d [SE 19.0] for the control, 33-BR, 67-BR, and 100-BR, respectively), implying less water loss by other means such as evaporation when brackish water was consumed. Total tract OM digestibility was lower ( = 0.049) for treatments with brackish water than for treatments without brackish water (64.2, 61.5, 58.6, and 59.3% [SE 1.86] for the control, 33-BR, 67-BR, and 100-BR, respectively), although ME intake was similar among treatments ( = 0.940; 4.61, 4.57, 4.60, and 4.31 MJ/d [SE 0.394] for the control, 33-BR, 67-BR, and 100-BR, respectively). Daily heat energy in kilojoules per kilogram BW was less with brackish water than without brackish water ( = 0.001; 474, 436, 446, and 445 kJ/kg BW [SE 7.7] for the control, 33-BR, 67-BR, and 100-BR, respectively), although values in megajoules were similar among treatments ( = 0.588; 4.36, 4.12, 4.22, and 4.18 MJ [SE 0.124] for the control, 33-BR, 67-BR, and 100-BR, respectively). Body weight of wethers consuming brackish water decreased less than that of wethers consuming the control water ( = 0.006; -37, -14, -7, and -16 g [SE 7.2] for the control, 33-BR, 67-BR, and 100-BR, respectively), but recovered energy was similar among treatments ( = 0.923; 0.25, 0.45, 0.38, and 0.13 MJ/d [SE 0.356] for the control, 33-BR, 67-BR, and 100-BR, respectively). In conclusion, brackish water inclusion in drinking water had a number of effects, but it does not appear that consumption of this source would adversely impact performance of growing meat goats.

Effects of conditions of an experimental model to evaluate methods of electric-fence strand addition to barbed-wire fence to contain goats

Growing meat goats of 4 types (Boer and Spanish of both wethers and doelings) were used to evaluate conditions for a method of testing efficacy of electric-fence strand additions to barbed-wire fence used for cattle to also contain goats. Animals were allocated to 8 sets, with each set consisting of 5 groups. There was 1 goat of each of the 4 types in a group. One side of five 2.4- × 3.7-m evaluation pens consisted of barbed-wire strands at 30, 56, 81, 107, and 132 cm from the ground. Evaluation pens were adjacent to a pasture with abundant vegetation. Fence treatments (FT) were electrified strands (6 kV) at 15- and 43- (LowHigh), 15- and 23- (LowMed), 15- (Low), 23- (Med), and 43-cm (High), where Low, Med, and High abbreviations are for low, medium, and high heights from the ground, respectively. For adaptation, there were 4-wk and sequential exposures to evaluation pens: wk 1, no electric strands; wk 2, 1 strand at 0 kV; wk 3, LowHigh; and wk 4, LowHigh. There were 6 periods for measurements, each separated by 1 wk. During the 1-wk intervals on pasture, sets were exposed to 1 interval treatment without and another with 2 electric strands (6 kV) positioned next to supplement troughs, to potentially affect familiarity with electrified strands and influence subsequent behavior. All animal sets were used for measurements in period 1 in a completely randomized design (CRD). Four sets were also used in 4-wk subsequent measurement periods for a 5 × 5 Latin square (LS). All animal sets were exposed to the same FT in period 6 as in period 1. Behavior in evaluation pens was observed for 1 h with a video surveillance system in the 6 periods. There were no effects of gender and few and minor effects of preliminary and interval treatments. The percentage of animals that exited evaluation pens differed (P < 0.05) among FT, with the CRD approach in period 1 (25%, 47%, 38%, 66%, and 84%; SEM = 8.0) and with repeated measures in periods 1 and 6 (6%, 22%, 22%, 63%, and 81% for LowHigh, LowMed, Low, High, and Med, respectively; SEM = 4.9), and between breeds in periods 1 (34% and 70%) and 1 and 6 (28% and 50% for Boer and Spanish, respectively). For the LS approach, FT affected exit (31%, 23%, 16%, 35%, and 30%; SEM = 5.3) and breeds differed (P < 0.05), as well (12% and 43%). Exit decreased as period advanced (60%, 35%, 23%, 10%, and 8%, for 1, 2, 3, 4, and 5, respectively; SEM = 5.3). In conclusion, breed should be considered in the model being developed. A LS approach was not suitable, but a CRD experiment after these adaptation procedures appears promising.

Effect of Ovar-DRA and Ovar-DRB1 genotype in small ruminants with haemonchosis

The effect of Ovar‐DRA and Ovar‐DRB1 genotypes on faecal egg count (FEC) was determined in sheep and goats infected with Haemonchus contortus. One hundred and forty‐three sheep from 3 different breeds (St. Croix, Katahdin and Dorper) and 150 goats from three different breeds (Spanish, Boer and Kiko) were used. Parasitological (FEC), haematological (packed cell volume) and immunological (IgA, IgG and IgM) parameters were measured. Sheep populations showed a higher FEC and humoural response than goat breeds. Genotypes were determined by high‐resolution melting assays and by conventional PCR. For Ovar‐DRA, sheep and goats carrying the AA genotype showed significant lower FEC than AG and GG genotypes. The additive effect was found to be 115.35 less eggs per gram of faeces for the A allele for goats. For Ovar‐DRB1, only in sheep, the GC genotype was associated with low FEC. The additive effect was 316.48 less eggs per gram of faeces for the G allele, and the dominance effect was 538.70 less eggs per gram of faeces. The results indicate that single nucleotide polymorphisms within Ovar‐DRA and Ovar‐DRB1 could be potential markers to be used in selection programmes for improving resistance to Haemonchus contortus infection.