S. P. Hart

Relationships among forage chemistry, rumination and retention time with intake and digestibility of hay by goats☆☆☆

Eight species of forage, a cool-season perennial (tall fescue ( Festuca arundinacea)) and annual grass (winter wheat (Triticum aestivum)), four warm-season perennial grasses (caucasian (Bothriochloa caucasica), plains (B. ischaemum), old world bluestem, bermudagrass (Cynodon dactylon), and eastern gamagrass (Tripsacum dactyloides)), a warm season annual (crabgrass (Digitaria sanguinalis)) and a perennial legume (alfalfa (Medicago sativa)), were each cut at two or three maturities to provide a wide array of quality difference (n = 20). Twenty wether goats (Capra hicus) were fed the hays in four different trials using an incomplete block design so that four different goats received each hay. Alfalfa produced the highest (25 g kg −1 body weight (BW)) and wheat the lowest (13.6 g kg −1 BW) organic matter (OM) intake. A number of the grasses provided less than 20 g kg −1 BW OM intake. Digestion of OM was also highest for alfalfa (>715 g kg −1 ) and lowest for bermudagrass (508 g kg −1 ). All measures and expressions of intake and digestibility were better related to ruminating and retention time than to forage chemistry, with the exception of crude protein digestibility. The best equations for predicting intake included a combination of mean retention time and forage acid detergent fiber (ADF) content (reciprocal and quadratic); that for digestibility included permanganate lignin (reciprocal), and the quadratic for ruminating and retention time. Equations for predicting the constraint on intake and digestible organic matter intake produced higher r 2 than those for either intake or digestibility. Digestibility of ADF and neutral detergent fiber (NDF) were poorly predicted with either chemistry ( r 2 ≤ 0.20), or ruminating time (r 2 = 0.43), but combinations of permanganate lignin content of NDF, retention and ruminating time produced reasonable equations. Published by Elsevier Science B.V.

ASAS Centennial Paper: Impact of animal science research on United States goat production and predictions for the future

Goat research in the United States has increased but at a rate less than that in production. Research on goat meat includes nutritional quality, packaging, color, sensory characteristics, and preslaughter management. Goat skins have value for leather, but quality of goat leather has not been extensively studied. Research in the production, quality, antibiotic residues, and sensory characteristics of goat milk and its products has aided development of the US dairy goat industry. Limited progress has been made in genetic improvement of milk or meat production. There is need to explore applications of genomics and proteomics and improve consistency in texture and functionality of goat cheeses. New goat meat and milk products are needed to increase demand and meet the diverse tastes of the American public. Despite research progress in control of mohair and cashmere growth, erratic prices and sale of raw materials have contributed to further declines in US production. Innovative and cooperative ventures are needed for profit sharing up to the consumer level. Internal parasites pose the greatest challenge to goat production in humid areas largely because of anthelmintic resistance. Study of alternative controls is required, including immunity enhancement via nutrition, vaccination, pasture management such as co-grazing with cattle, and genetic resistance. Similarly, the importance of health management is increasing related in part to a lack of effective vaccines for many diseases. Nutrition research should address requirements for vitamins and minerals, efficiencies of protein utilization, adjusting energy requirements for nutritional plane, acclimatization, and grazing conditions, feed intake prediction, and management practices for rapid-growth production systems. Moreover, efficient technology transfer methods are needed to disseminate current knowledge and that gained in future research.

Effects of dietary tallow level on performance of Alpine does in early lactation

Sixty Alpine does (initial BW 47+/-1.3kg) were used to determine effects of dietary inclusion of different levels of partially hydrogenated tallow on performance in early lactation (weeks 3-11). Treatments entailed a 30% concentrate, negative control (NC) diet and five diets higher in concentrate (42-46%) with 0, 1.5, 3.0, 4.5 or 6.0% DM of partially hydrogenated tallow (0T, 1.5T, 3.0T, 4.5T and 6.0T, respectively). DM intake was 1.54kg per day for the NC and 1.86, 1.80, 1.99, 2.17 and 1.96kg per day for the five tallow treatments, respectively, BW was similar among treatments and increased as the trial progressed (47.4, 48.4, 49.8, 50.4, 50.8 and 51.3kg at weeks 3, 5, 7, 9, 11 and 13, respectively). Milk yield was lower (P<0.05) for NC (2.61kg per day) compared with the mean of the other diets and changed quadratically (P<0.05) as tallow level increased (2.85, 3.08, 3.14, 3.21 and 2.69kg per day for the five tallow treatments, respectively). Milk fat concentration was lower (P<0.05) for NC (2.94%) than for the mean of other diets and increased linearly (P<0.05) with increasing tallow level (3.00, 3.17, 3.34, 3.48 and 3.58%) whereas, milk protein concentration was not affected by level of tallow (2.72, 2.80, 2.93, 2.85, 2.90 and 2.90% for NC, and the five tallow treatments, respectively). The estimated NE(l):4% fat-corrected milk yield ratio was 0.93Mcal/kg for NC and 1.30, 1.11, 1.21, 1.37 and 1.44Mcal/kg for the five tallow treatments, respectively. The results indicated that in Alpine does, milk yield in early lactation increased as dietary tallow level was increased to 3 and 4.5% but decreased when the level was increased to 6%, although milk fat concentration increased linearly and the protein level was unchanged. These results suggest beneficial usage by lactating Alpine does of low to moderate levels of partially hydrogenated tallow in diets moderate in concentrate level, although ingredient availability and costs will influence ultimate dietary ingredient decisions.

Comparative study of the effects of testing laboratory, counting method, storage and shipment on somatic cell counts in goat milk

Abstract Somatic cell counts (SCC) in goat milk from different stages of lactation were determined at four laboratories (I, II, III and IV) using the pyronin Y-methyl green (PYMG) direct microscopic method and/or Fossomatic machines calibrated with either goat or cow milk standards. The effects of sample shipment and storage on SCC of goat milk were also determined. Results of this study indicated that the PYMG microscopic method and the Fossomatic machine calibrated with goat milk standards gave comparable estimates of SCC in goat milk (p>0.05). However, on average the Fossomatic machines (n=3) calibrated with cow milk standards estimated SCC of goat milk to be 24.5% higher than a Fossomatic machine calibrated with goat milk standards (p 0.05) between laboratories (n=2) when the PYMG microscopic method was used. Shipping milk samples in an ice box (3 days) and storing in a refrigerator (3 days) did not affect SCC results (p>0.05).

Effects of dietary protein level on performance of Angora and cashmere-producing Spanish goats

Abstract Effects of dietary crude protein level on fiber production of Angora and cashmere-producing Spanish goats were studied in 16 yearling doelings (eight Spanish, eight Angora) for 8 weeks. Goats were housed in individual stalls and maintained at constant temperature (21 °C) with 9 h light and 15 h darkness each day. Goats were initially sheared, blocked by body weight (BW) and assigned to one of two dietary treatments (8% or 16% crude protein (CP)) in a 2 × 2 factorial design. Diets were isocaloric (2.9 Meal kg −1 digestible energy (DE)) and were fed ad libitum. Dry matter intake (DMI) was similar for Angora and cashmere-producing Spanish goats. Daily DMI (612 vs. 892 g day −1 ) and BW gain (38 vs. 127 g day −1 ) were greater ( P −1 ) and BW gain (55 vs. 116 g day −1 ) were also increased ( P −1 ) increased ( P P P P P P P P P > 0.05) by diet CP level for cashmere-producing Spanish goats. Increasing diet CP level increased mohair production, diameter and staple length, but had little effect on cashmere fiber production. Increasing dietary protein also increased DMI, BW gain and feed efficiency in both types of goats.

Determination of fetal numbers in Alpine does by real-time ultrasonography

Abstract Pregnancy diagnosis was carried out in Alpine does using a real-time ultrasound instrument equipped with a 5 MHz sector array probe. Eighty Alpine does were examined 5 and 7 wk after breeding. Does were restrained while standing, and the transducer probe was placed on the hairless caudal ventral abdominal wall cranial to the udder. Non-pregnant does were readily and accurately recognized at 5 and 7 wk after breeding. Number of fetuses per doe at 5 wk of gestation was different (P 0.2) to the number born. Accuracy for determining singles, twins, and triplets at 5 wk of gestation was 44, 73, and 67%, respectively; at 7 wk of gestation it was 82, 89 and 100%, respectively. This accuracy is similar to that reported in ewes. It was concluded that real-time ultrasonography scanning by the transabdominal route is a reliable method for early pregnancy diagnoses in goats. The technique also enables accurate separation of does carrying singles, twins, and triplets as early as 7 wk in gestation. Such information can be useful for improved nutritional management.

Effects of mimosine administered to a perfused area of skin in Angora goats

The effect of mimosine on a perfused area of skin tissue was studied using an isolated perfusion technique. Four mature Angora wethers (body weight 35 (SE 2.3) kg) were cannulated bilaterally with indwelling silicone catheters in the superficial branches of the deep circumflex iliac artery and vein. Mimosine (40 mg/kg metabolic weight (W)0.75) per d) was infused intra-arterially into one iliac artery of each goat for 3 d and saline was infused in the contralateral (control) iliac artery. Iliac venous blood samples were taken from both sides along with arterial samples from the carotid artery. Mimosine infusion elevated plasma mimosine in the carotid artery (52.6 (SEM 19.21) mumol/l) and iliac vein on the saline-treated side to 54.1 (SEM 16.31) mumol/l and in the iliac vein on the mimosine-treated side to 191.3 (SEM 19.14) mumol/l (P < 0.01). Mimosine decreased feed intake (2.3 v. 0.6 kg/d, SEM 0.29; P < 0.001) and water consumption (5.2 v. 1.3 litres/d, SEM 0.67; P < 0.001). Mimosine did not cause defleecing in the area of infusion and was cleared from the bloodstream within 12 h of cessation of infusion. The following effects were also observed during mimosine infusion: decrease in plasma amino acids to half pre-infusion values (methionine 22.7 v. 13.1 mumol/l, SEM 1.41; lysine 95.9 v. 37.4 mumol/l, SEM 4.28; P < 0.001); decreases in plasma triiodothyronine (1495 v. 695 ng/l, SEM 43.1; P < 0.001), thyroxine (61.5 v. 19.5 micrograms/l, SEM 1.8; P < 0.001) and insulin (28.7 v. 17.3 microIU/ml, SEM 1.89; P < 0.01) concentrations; increase in plasma cortisol (14 v. 62 micrograms/l, SEM 0.35; P < 0.001) concentration; decreases in levels of plasma Zn and Mg (0.97 v. 0.49 mg/l, SEM 0.063; P < 0.001 and 21.4 v. 14.6 mg/l, SEM 1.74; P < 0.001 respectively). All reported variables returned to their normal values 24 h after cessation of mimosine infusion except feed intake which was affected for a longer period. Mohair length and diameter were not affected by mimosine infusion. The toxicity of mimosine may be due to the drastic depletion of Zn and Mg in the blood as mimosine possesses very strong chelating properties and is excreted in the urine as a chelate.

Effects of Gender and Age on Performance and Harvest Traits of Boer × Spanish Goats

Abstract Cameron. M.R., Hart, S.P., Sahlu, T., Gilchrist, C., Coleman, S.W. and Goetsch, A.L. 2001. Effects of gender and age on performance and harvest, traits of Boer × Spanish goats. J. Appl. Anim. Res., 20: 141–155. Sixty Boer × Spanish goats ware used to determine, effects of gender and age on performance and harvest triats. Wethers, females and males (16.8, 15.6 and 16.9 kg initial body weight, respectively) consumed a high concentrate diet from 116 to 340 d of age, with harvest at. 56-d intervals. Average dry matter intake for the entire experiment was lowest among genders for females (671, 534 and 682g/d; P<0.05) and average daily gain was greater for males and wethers than for females (119, 89 and 138 g/d for wethers, females and males, respectively; P<0.05). Dressing percentage was similar among genders and lowest among ages at. 116 d (41.7, 48.5, 49.9, 51.3 and 50.9% for 116, 172, 228, 281 and 340 d, respectively; P<0.05). internal fat mass was lower (P<0.05) for males than for wethers and females (5.1, 6.9 and 7.0% empty body weight, respectively) and increased with age (2.3, 5.4, 6.3, 7.7 and 9.9% empty body weight; 0.32, 1.08, l.60, 2.77 and 1.08 kg at ll6, 172, 228 and 340 d of age, respectively). Carcass scores and grades were similar among genders. Among genders, males had the greatest (P<0.05) carcass percentages of separable bone (27.1, 27.0 and 29.4%) and lean (50.1, 49.7 and 54.1%) and were lowest in fat (18.0, 19.5 and 12.7% for wethers, females and males, respectively). Carcasses were having 38.9, 29.9, 27.0, 22.6 and 20.7% hone; 0.7, 18.3, 15.1, 21.0 and 22.4% fat; and 49.4, 48.5, 50.9, 53.9 and 53.8% lean at 116, 172, 228, 284 and 340 d, respectively. In summary, differences among genders of Boer crossbred goats in performance and harvest traits were not influenced by age between approximately 4 and 11 mo. However, changes in carcass characteristics differed between 4 and 6 mo of age more than from 6 to 11 mo; and mass of internal fat increased with age and was nearly as great, as that of carcass fat at each age.

Effects of lysine and hormones on amino acid concentration in the skin of Angora goats

Abstract The effects of lysine and hormones on amino acid and glucose venous outflow in the skin and the whole body were determined in Angora wethers (n = 5). The goats had chronically catheterized superficial branches of the deep circumflex iliac artery and vein of each side. Four experiments involved the intra-arterial test infusion on one side (60 min) of lysine (0, 0.16, 0.8 and 4mgh−1; Experiment 1) alone and lysine (4mgh−1) together with infusions (60min) of successively increasing doses of insulin (0, 0.1, 1 and 10mUh−1; Experiment 2), cortisol (0, 0.15, 1.5 and 15 μgh−1; Experiment 3), and triiodothyronine (T3), 0, 0.02, 0.2 and 2 μgh−1; Experiment 4). The other side served as control and was infused with saline only (10 ml h−1). Lysine concentrations in venous outflow from the control side (80.9 μM) were unaffected by lysine infusion, whereas venous lysine concentrations in the test side were 82.1, 85.7, 96.9 and 109 μM during lysine infusion at 0 mgh−1, 0.16 mgh−1, 0.8 mgh−1 and 4 mgh−1, respectively. Although venous concentrations of insulin (approximately 22 μU ml−1) were similar (P > 0.05) and unchanged in both sides for all doses of insulin infused, the highest dose of insulin infusion (10 μUh−1) decreased (P 0.05) by cortisol despite six- to ten-fold increase in the plasma cortisol concentration. The highest dose of T3 (2 μgh−1 increased (P

Local infusion of glucose and insulin in isolated skin perfusion sites in Angora goats

Abstract Six Angora goats (average BW 35.0 ± 2 kg) were implanted bilaterally with silicon catheters in the superficial branch of the deep circumflex iliac artery and in the superficial branch of the deep circumflex iliac vein to determine the utilization of glucose and its insulin dependency in skin tissue. Intraarterial glucose infusion (Espt. 1) of 15 and 150 mg/h did not change glucose level in venous blood drained from that region. However, infusion of 750 mg/h of glucose increased venous blood glucose level by 87.9% (66.3 vs. 124.6 mg/dl; P