Efficacy of ivermectin in reducing gastrointestinal nematode fecal egg counts in goats in Burundi

Cross-bred goats in Burundi infested with gastrointestinal nematodes were submitted to fecal investigations and injected subcutaneously with ivermectin. In Experiment 1, goats were treated with 200 μg kg⁻¹ bw ivermectin. In Experiment 2, animals were administered twice that dose. In Experiment 3, goats suspected to be resistant to other anthelmintics were treated with 200 μg kg⁻¹ bw ivermectin. In Experiment 4, two doses of the same strength were injected with an interval of 7 days. Results demonstrate that 200 μg kg⁻¹ bw ivermectin is effective for the control of gastrointestinal nematodes of goats in Burundi; this dosage is also effective against nematodes suspected to be resistant to other anthelmintics. The administration of 400 μg kg⁻¹ bw did not induce greater or more prolonged effectiveness percentages. The supposed decrease of ivermectin's residual activity on Day 28 might be avoided by administering two doses with an interval of 7 days. No adverse effects were observed in treated animals.     

Immunoglobulin G concentration and neonatal survival of goat kids delivered in a pen or on open range

To determine whether kids born on open range (subjected to stress due to management practices) had lower IgG concentrations and a higher mortality risk than kids born in a pen, serum IgG concentrations in 63 one-day-old kids were determined. Median Serum IgG concentrations one day after birth tended to be lower (p=0.09) in surviving kids born in the open than that of surviving kids delivered in pen (115 vs. 1119 mg dl⁻¹). However, survival risk (71 and 82% for kids born on the open range and pen, respectively; n=79) were not significantly affected by site of kidding. Median IgG concentration of surviving kids born on a pen was not significantly different (p=0.13) compared to non-surviving kids (1118 vs. 115 mg dl⁻¹). No differences were detected in either median serum IgG levels or death rates between male and female kids. Kids with IgG concentrations <800 mg dl⁻¹ showed lower survival risks than those with higher concentrations. We concluded that typical management practices of kids delivered on open range at a goat operation under extensive conditions in northern Mexico tended to reduced colostrally acquired serum immunoglobulin levels, but had no effect directly on mortality.     

Goat flea (order Siphonaptera) as a possible vector for the transmission of caprine mycoplasmal polyarthritis with septicaemia

Goat fleas of the order Siphonaptera were collected from the body surfaces of naturally infected polyarthritic goat kids with septicaemia. These fleas and the infected kids were positive for Mycoplasma mycoides subsp. mycoides (large colony type) identified by cultural, morphological, biochemical and growth inhibition tests. Blood from the infected fleas contained 1 × 10²−1 × 10⁵ viable subsp. mycoides ml⁻¹. Experimental transmission of the disease to other kids was established by placing 120 infected fleas on each kid's body surfaces. All experimentally infected kids developed characteristic clinical signs and showed leucopenia with neutropenia, an increased amount of fibrinogen and mortality with lesions of suppurative polyarthritis associated with septicaemia. The organisms were also recovered in high numbers from heart blood, body fluids, and infected organs and joints. The results suggested that fleas of the order Siphonaptera acted as vectors for the transmission of the spontaneous disease in kids.     

Efficacy of spheroplastic and cell-wall competent vaccines for Mycobacterium avium subsp. paratuberculosis in experimentally-challenged baby goats

A Mycobacterium avium subspecies paratuberculosis (MAP) vaccine that reduced the incidence of clinical disease or reduced fecal shedding of MAP would aid control of Johne's disease (JD). The objective of the present study was to evaluate the efficacy of four MAP vaccine combinations, including cell-wall competent (CWC) alum adjuvant, CWC-QS21 adjuvant, cell-wall deficient (CWD) alum adjuvant and CWD-QS21 adjuvant vaccines. Eighty baby goats were vaccinated at 1 and 4 weeks of age with one of these vaccines or a sham control vaccine consisting of alum adjuvant. Kids were challenged orally with approximately 6.0 × 10⁹ organisms in four divided doses of 1.5 × 10⁹ organisms using a goat isolate of MAP. Vaccinated challenged and challenged control groups had 10 and 6 kids per group, respectively. Half of the kids within each group were necropsied at either 6 or 9 months post-challenge. Gross and microscopic lesions and relative number of acid-fast bacilli were evaluated and scored at necropsy. Results indicated all challenged kids had some lesions compatible with JD suggesting none of the vaccines prevented infection. Three vaccines (CWC-alum, CWC-QS21 and CWD-QS21) reduced lesion scores by 46–51% at 9 months. CWD-alum vaccine resulted in a more severe (+33.5%) lesion score than sham-vaccinated challenged control. Lesion scores were greater at 9 months than at 6 months post-challenge in the sham-vaccinated challenged group and CWD-alum vaccinated group, while lesion scores were generally stable with remaining vaccines. Mean fecal CFU/g were significantly different across time from challenge to 9-month necropsy (p = 0.043) and the CWC-QS21 vaccine group had a marked reduction in fecal CFU/g at all time points post-challenge. A reduction in MAP CFU/g was also detected in necropsy tissues from kids given the CWC-alum, CWC-QS21 and CWD-QS21 vaccines, and increased CFU/g were detected in tissues from kids given the CWD-alum vaccine. Immunological tests evaluated included, humoral response evaluation by AGID, ELISA and Western blot, and cell mediated response by comparative PPD skin testing (M. avium, Old Johnin, M. bovis and Lot 2 Johnin PPD's), and production of MAP induced γ-interferon. Vaccination also resulted in false-positive PPD skin test reactions for M. avium PPD, Old Johnin PPD and γ-interferon tests. When a 2-mm cutoff above normal skin thickness was used to define positive skin test reactions, false-positive reactions for M. bovis were detected in only 2 of 32 kids given a vaccine with QS21 adjuvant.     

Dynamics of the free-living populations of gastrointestinal trichostrongyles of cattle in a natural grazing system in Guadeloupe (French West Indies)

The variations in the population size of trichostrongyle infective larvae (L3) in a cow-calf system were recorded for two years in Guadeloupe (humid and hot tropical climate). Calvings were pooled during the dry season for two herds and during the rainy season for two others. Each herd grazed three paddocks of natural pasture according to a rotational system (14 days of grazing per paddock). At the time the animals entered each paddock, the numbers of L3 on pasture were assessed around fecal pats (L3_ap) and within a 1 m radius of pats (L3_1rfp). Seventy-one regressor variables were tested to explain variations in the size of L3 populations: combinations of variables linked to animals (e.g. weight, fecal eggs, stocking rate) and combinations of ecological variables (e.g. rainfall, global radiation, herbage mass). L3_1rfp were highly correlated to L3_ap. However, when the mean global radiation during the third week after the entrance of animals exceeded 20 MJ m⁻² day⁻¹, L3_1rfp was undetectable even with large L3 burdens around pats. Multiple-component analysis and hierarchical classification used on regressor variables led to four classes which were characterized basically by fecal eggs and stocking rate, but not by climatic conditions. Within these classes, there was a limit of global radiation between 8 and 14 days after the entrance of animals; beyond this limit (20 MJ m⁻² day⁻¹), the L3_ap decreased from 1.3 to 27.1 times. The classification factor and global radiation factor explained 50–57% of the variance of L3_ap. From these results, it can be concluded that animal husbandry is just as important as climatic conditions in explaining the number of L3 on pasture in Guadeloupe. Global radiation, fecal eggs and stocking rates appeared to be useful in predicting the level of infectivity of pastures.     

Responses of female lambs to Rev-1 (brucellosis) vaccination

In order to investigate Rev-1 vaccination immunogenicity, 60 indigenous (Makuii) non-infected female lambs 3–4 months of age in northwestern Iran were systematically divided into two groups: 40 into a treatment (T) group and 20 into a control (C) group. Lambs in Group T received 1 ml of Rev-1 vaccine by s.c. injection and blood samples were collected from both groups at 15 days and 2, 4, 6, 8, 10, 12 and 14 months after vaccination. The seroagglutination test (SAT) and the 2-mercaptoethanol test (2-MET) were carried out on the sera. Control lambs were negative in all the examinations. The results of the SAT showed that the mean( ± SD) antibody titre of lambs in Group T was maximum (725 ± 112 IUml⁻¹) at Day 15, then declined gradually until the fourth month and was in the normal range (31 IU ml⁻¹) thereafter. The results of the 2-MET were negative in Group C but in Group T the antibody titre was at a maximum level (161.7 ± 46.6 IUml⁻¹) at Day 15, decreased to 1.2 ± 2.5IUml⁻¹ at 4 months post-vaccination and was negativ; thereafter. In the second part of the trial, 20 vaccinated and ten control lambs received 0.25 ml melitin by i.d. injection 10.5 months after vaccination. The control group showed no reaction but 13 (65%) of the vaccinated lambs showed an oedematous swelling at the site of injection within 48 h, which indicated that the delayed-type hypersensitivity test (DTHT) could be useful in the diagnosis of Brucella infection in lambs. In the third stage of the experiment, four vaccinated and three control lambs were injected with Brucella melitensis strain 16M at a rate of more than 123 × 10⁶ bacteria per lamb 14 months after vaccination. Rectal temperature (Tem), heart-rate (HR) and respiration rate (RR) were measured three times a day (at 08:00, 14:00 and 21:00 h) 3 days before until 9 days after injection. SAT was carried out on the day before injection and at the time of slaughter. The mean Tem, HR and RR did not significantly change but the mean( ± SD) SAT titre in the T lambs 9 days after injection was 47.5 ± 9.9 IU ml⁻¹ (vs. 8.66 ±6.1 IU ml⁻¹ in the control lambs) (P < 0.01). All lambs were slaughtered on the ninth day. Fewer bacterial cultures of samples taken from the uterus, spleen, liver and lymph nodes were positive in T lambs compared with the controls. The lower proportion of Brucella-positive lambs in the vaccinated group compared with the control group indicates that vaccination with Rev-1 improved the resistance of lambs to the experimental infection.     

Effect of a nonsteroidal aromatase inhibitor on in vitro and in vivo secretion of estradiol and on the estrous cycle in ewes.

Three experiments were performed to study effects of decreased concentrations of estradiol-17β (E₂) on lifespan and function of ensuing ovine corpora lutea (CL). In experiment 1, 52 follicles were collected from 10 ewes and placed into individual culture with 0 or .01 μCi ³H-androstenedione (10 ng; ³H-A) and 0, 10⁻¹¹, 10⁻⁹, 10⁻⁷, or 10⁻⁵ M of a nonsteroidal aromatase inhibitor, CGS16949A (CGS). Concentrations of E₂ secreted into the medium, and synthesis of estrogens as estimated by formation of ³H-water from ³H-A were decreased by 10⁻⁵ and 10⁻⁷ (P<.01), but not 10⁻⁹ or 10⁻¹¹ M CGS. In experiment 2, luteolysis was induced in 24 ewes by injection of PGF₂ on days 5 to 10 of the estrous cycle (0 hr). Ewes received 0, 0.5, 1.0, 2.0 or 4.0 mg CGS per kg BW i.v. at −12, 0, 12 and 24 hr, and an ovulatory dose of hCG at 36 hr. Jugular (P<.001) and vena caval (P<.001) concentrations of E₂ were decreased by CGS at all doses tested for 8 to 10 hr, but had returned to levels similar to control ewes by the time of the next injection. Concentrations of E₂ around the time of the LH surge were similar in control and treated ewes. During the subsequent luteal phase, concentrations of progesterone (P₄) were similar in control and treated ewes. Thus, transient decreases in E₂ during the follicular phase were not deleterious to the subsequent luteal phase. In experiment 3, luteolysis was induced in 18 ewes by injection of PGF₂ on days 6 or 7 (0 hr) of the estrous cycle. Ewes received 0 or 1 mg CGS per kg BW i.v. every 8 hr from 0 to 40 hr. Ovulation was induced with hCG at 36 hr. CGS reduced jugular (P<.001) and vena caval (P<.001) concentrations of E₂, prevented an endogenous surge of LH (P<.05) and increased (P<.001) concentrations of FSH. All ewes had ovulated a marked follicle by 72 hr, but onset of the luteal phase, as assessed by concentrations of P₄, was delayed (P<.01) in ewes receiving CGS. Delayed luteal phases were not solely attributable to the presence of new CL or to luteinization of follicular cysts. When data were aligned according to the day ewes were observed in estrus, profiles of P₄ did not differ with treatment. Therefore, normal luteal function ensued following estrus whether or not ewes re-ovulated. In conclusion, decreased secretion of E₂ by the preovulatory follicle was not involved in the ontogeny of CL of short lifespan or subnormal function. Instead, adequate production of E₂ or precisely timed E₂ secretion may be required during follicular development for subsequent functional luteinization.     

Efficacy of amprolium for the treatment of pathogenic Eimeria species in Boer goat kids

This study evaluated the efficacy of two different doses of amprolium in goats heavily infected with pathogenic Eimeria species. Forty Boer goat kids ranging from 3 to 5 months of age with naturally occurring coccidiosis were randomly divided into 2 groups and treated orally with amprolium at doses of 10mg/kg daily for 5 days (n=20) or 50mg/kg daily for 5 days (n=20). The Eimeria oocyst per gram concentrations were significantly reduced on day 7 in the kids that received amprolium at 50mg/kg, however oocyst concentrations were not significantly reduced in goats that received the 10mg/kg dose. Out of 100 Eimeria oocysts identified from a pooled fecal sample, E. christenseni was the most frequently identified (52%) coccidial species present. The results of this trial indicate that amprolium can be an effective treatment for pathogenic Eimeria species in goat kids, however higher and extralabel doses (50mg/kg) should be used.     

Dose effect of human growth hormone-releasing factor and thyrotropin-releasing factor on hormone concentrations in lactating dairy cows

Two experiments were conducted to study the effects of growth hormone-releasing factor (GRF) and thyrotropin-releasing factor (TRF) administration on hormone concentrations in dairy cows. In the first trial, 12 cows were used on 5 consecutive days to determine the effect of four sc doses of GRF (0, 1.1, 3.3 and 10 μg•kg⁻¹ BW) and three sc doses of TRF (0, 1.1 and 3.3 μg•kg⁻¹ BW) combined in a factorial arrangement. GRF and TRF acted in synergy (P = .02) on serum growth hormone (GH) concentration even at the lowest dose tested and GH response to the two releasing factors was higher than the maximal response observed with each factor alone. TRF increased (P<.01) prolactin (Prl), thyrotropin (TSH), triiodothyronine (T₃) and thyroxine (T₄) concentrations similarly at the 1.1 and 3.3 μg•kg⁻¹ doses and GRF did not interact (P>.40) with TRF on the release of these hormones. In the second trial, the effect of GRF (3.3 μg•kg⁻¹ BW, sc) and TRF (1.1 μg•kg⁻¹ BW, sc) was tested at three stages (18, 72 and 210 days) of lactation on serum Prl and TSH concentrations. Eighteen cows (n = 6 per stage of lactation) were used in two replicates of a 3 × 3 latin square. The TRF and GRF-TRF treatments were equipotent (P>.05) in increasing Prl and TSH concentrations. Prl and TSH responses were similar (P>.40) throughout lactation. In summary, GRF at doses ranging from 1.1 to 10.0 μg•kg⁻¹ and TRF at doses ranging from 1.1 to 3.3 μg•kg⁻¹ act in synergy on GH release and do not interact on Prl, TSH, T₃ and T₄ concentrations in dairy cows. Furthermore, Prl and TSH response to TRF are not affected by stage of lactation.     

Studies on activation and levels of haemolytic complement of buffalo (Bubalus bubalis). II. Alternate complement pathway activity in serum.

Buffalo serum caused lysis of unsensitized red blood cells (RBC) of sheep, goat, rabbit and guineapig. There was minimal lysis of cattle RBC, and homologous RBC were resistant. Lysis of sheep and goat RBC was the result of natural antibodies as adsorption with respective RBC and addition of 8 mmol ethylene glycolbistetraacetate (EGTA) in diluent completely abrogated the haemolytic activity. The lysis of guinea-pig and rabbit RBC was only partially decreased by these treatments, indicating the presence of alternate complement pathway (ACP) activity in buffalo serum. The guinea-pig RBC were the most sensitive to lysis, and 50% CH titre units above 40 ml⁻¹ of serum were obtained. The haemolytic activity of buffalo C for unsensitized guinea-pig RBC was reduced from 47 CH₅₀ units to an undetectable level by heating at 50°C for 20 min and at 56°C for 4 min. Similarly, treatment with zymosan also inhibited this haemolytic activity. Maximum activation of buffalo ACP occurred in the presence of 4 mmol Mg²⁺ in the diluent.

Using standardized conditions, ACP activity was determined in sera of 98 healthy buffaloes of different age groups from 1 month to 12 years. Even young calves less then three months of age showed considerable ACP activity (45.60±1.21 CH₅₀ units ml⁻¹) which increased with age. The peak mean values of 79.79±1.45 CH₅₀ units was recorded in 2 to 4-year-old animals. However, in all the 11 animals above 4 years of age, the haemolytic activity was greatly reduced and was even less than that in 1 to 3-month-old buffalo calves. Haemolytic activity did not vary between the sexes.     

Perforin expression can define CD8 positive lymphocyte subsets in pigs allowing phenotypic and functional analysis of natural killer, cytotoxic T, natural killer T and MHC un-restricted cytotoxic T-cells

In this study we have used the expression of perforin to characterize subsets of porcine cytotoxic lymphocytes. Perforin positive lymphocytes expressed both CD2 and CD8, most were small dense lymphocytes (SDL) and up to 90% were CD3 negative. However, the numbers of perforin positive T-cells increased with the age of the animal and their populations increased after specific antigen stimulation in vitro. The remaining perforin positive lymphocytes were large and granular and contained more CD3⁺CD5⁺CD6⁺ T-cells (−40%) of which a substantial proportion also co-expressed CD4. Perforin was expressed in subpopulations of both CD8 and CD8β lymphocytes, but was not expressed in γδ T-cells or monocyte/macrophages. The perforin positive CD3⁻ subset was phenotypically homogeneous and defined as CD5⁻CD6⁻CD8β⁻CD16⁺CD11b⁺. This population had NK activity and expressed mRNA for the NK receptor NKG2D, and adaptors DAP10 and DAP12. Perforin positive T-cells (CD3⁺) could be divided into at least three subsets. The first subset was CD4⁻CD5⁺CD6⁺CD11b⁻CD16⁻ most were small dense lymphocytes with cytotoxic T-cell activity but not all expressed CD8β. The second subset was mainly observed in the large granular lymphocytes. Their phenotype was CD4⁺CD5⁺CD6⁺CD8β⁺CD16⁻CD11b⁻ and also showed functional CTL activity. Thus not all of double positive T-cells are memory helper T-cells. The third subset did not express the T-cell co-receptor CD6, but up to half of them expressed another T-cell co-receptor CD5. The majority of this subset expressed CD11b and CD16, thus the third perforin positive T-cell subset was CD3⁺CD4⁻CD5⁺CD6⁻CD8β^±CD11b⁺CD16⁺, and possessed MHC-unrestricted cytotoxicity and LAK activity.     

Intraarticular Dirofilaria immitis microfilariae in two dogs

Medicinal plants have been investigated for their anthelmintic properties and shown to be effective against eggs and larvae of gastrointestinal nematodes. The aim of this study was to evaluate the efficacy of the Lippia sidoides essential oil (LsEO) on sheep gastrointestinal nematodes. Initially, 44 naturally infected sheep were divided and treated with 200 μg kg⁻¹ ivermectin and 230 and 283 mg kg⁻¹ LsEO, respectively, plus the control. Fecal samples were collected from each animal to determine epg at 7, 14 and 21 days after treatment. In another test, 21 sheep were distributed and treated with 200 μg kg⁻¹ ivermectin, 283 mg kg⁻¹ LsEO and the control, respectively. Seven days after treatment, they were euthanized and necropsied to count and identify the nematodes from the abomasum, small and large intestines. In the first test, the efficacy of 230 and 283 mg kg⁻¹ LsEO and ivermectin was 38%, 45.9% and 40.2%, respectively, 7 days after treatment, and 30%, 54% and 39.6%, respectively, 14 days after treatment. In the second experiment, the respective efficacy of 283 mg kg⁻¹ LsEO and ivermectin was 56.9% and 34.4% against Haemonchus spp., and 39.3% and 63.6% against Trichostrongylus spp.     

维生素K3对14日龄北京鸭凝血时间和维生素K依赖蛋白的影响

旨在研究维生素K₃对1~14日龄北京鸭凝血时间和维生素K依赖蛋白的影响,筛选评价肉鸭维生素K营养状况的敏感指标,并得到育雏期北京鸭饲粮维生素K₃适宜添加量。试验采用单因子完全随机试验设计,设6个维生素K₃添加水平（0、0.5、1、2、3和4 mg·kg^-1）,通过在玉米-大豆分离蛋白型基础饲粮中添加6个不同添加水平亚硫酸氢钠甲萘醌配制试验饲粮。将180只1日龄健康雄性北京鸭随机分为6个处理组,每处理组5个重复,每重复6只鸭。试验期14 d。结果表明：不同添加水平维生素K₃对1~14日龄北京鸭平均日增重、平均日采食量和料重比等生长性能指标未产生显著影响（P>0.05）。0和0.5 mg·kg^-1维生素K₃添加组凝血酶原时间显著高于2、3、4 mg·kg^-1维生素K₃添加组（P<0.05）。0 mg·kg^-1维生素K₃添加组血清凝血酶原前体蛋白水平显著高于0.5、1、2、3、4 mg·kg^-1维生素K₃添加组（P<0.05）;0 mg·kg^-1维生素K₃添加组血清羧化不全骨钙素水平显著高于2、3、4 mg·kg^-1维生素K₃添加组（P<0.05）。以凝血酶原时间、血清凝血酶原前体蛋白和羧化不全骨钙素为评价指标,采用折线模型估算1~14日龄北京鸭维生素K₃需要量分别为2.00、0.56和1.27 mg·kg^-1。综上,饲粮中添加维生素K₃可增强肉鸭凝血功能,降低血清凝血酶原前体蛋白和羧化不全骨钙素水平。在本试验基础饲粮条件下,以凝血酶原时间为评价指标,采用折线模型估测1~14日龄北京鸭维生素K₃需要量为2.00 mg·kg^-1。     

The C bicarbonate dilution technique to determine energy expenditure in young bulls validated by indirect calorimetry

We explored the applicability of the ¹³C bicarbonate dilution technique for determination of energy expenditure (EE) in young bulls in comparison to whole body indirect calorimetry (IC). Twelve bulls of a F2 German Holstein x Charolais cross (4.5 months, 332 ± 16 kg BM) received a diet providing 1000 kJ ME d^− 1 kg BM^− 0.75 and 4.3 g crude protein d^− 1 kg BM^− 0.75. Bulls were housed in respiration chambers and received an intravenous bolus of NaH¹³CO₃ (A: 3 μmol kg BM^− 1 (n = 2), B: 7 μmol kg BM^− 1 (n = 4), C: 17.5 μmol kg BM^− 1 (n = 6), 99 at.% ¹³C) into the jugular vein to measure EE. Simultaneously, EE was determined by IC. After the ¹³C administration blood samples and breath gas were collected from the animals in the respiration chamber during a 24-h period (7.00–7.00 h). The recovery of ¹³C in breath CO₂ (% of ¹³C dose) was irrespective of NaH¹³CO₃ dose (A: 69.7 ± 2.7%, B: 70.5 ± 4.5%, C: 75.0 ± 4.9%; P > 0.05). Only small amounts of ¹³C were excreted in urine (3.4 ± 2.6%) and feces (2.0 ± 1.3%). The EE determined by the ¹³C bicarbonate method using breath and blood ¹³C recovery rates as correction factors was not different from that measured by IC (816 ± 81 [blood] or 827 ± 101 [breath] vs. 820 ± 90 kJ d^− 1 kg BM^− 0.75). Bland–Altman analysis showed a 95% confidence interval for EE of ± 99 and ± 109 kJ d^− 1 kg BM^− 0.75 based on blood and breath ¹³C recovery, respectively. In conclusion, the ¹³C bicarbonate dilution method is appropriate to obtain reliable estimates of EE in young bulls using blood CO₂ or breath CO₂ under standardized experimental conditions, i.e. in the fasting state.     

纤维素复合酶对羔羊消化道组织结构的影响

为了探明纤维素复合酶提高羔羊饲料消化率的消化道组织学基础,选择刚出生且体重相近的波尔山羊公羔30只(20日龄开始自由采食优质苜蓿干草, 80日龄断奶)分为对照组和试验组(添加0.2%酶制剂),分别在2、3和4月龄每组各选体重相近的3只羔羊屠宰.结果表明,瘤胃乳头长度、宽度和单位面积瘤胃乳头表面积随月龄增加而增加,而单位面积乳头数随着月龄的增加而减少(P ＜ 0.01).酶制剂提高3、4月龄羔羊瘤胃乳头长度(P ＜ 0.01)、宽度(P ＞ 0.05)和单位面积瘤胃乳头表面积(P ＜ 0.01),减少单位面积乳头数(P ＜ 0.01).显著提高3月龄十二指肠肠绒毛的长度(P ＜ 0.05).在3、4月龄,酶制剂有增加小肠隐窝深度和黏膜厚度的趋势,但未达到显著水平(P ＞ 0.05).     

Energy expenditure in Awassi sheep grazing wheat stubble in the northern Negev Desert of Israel

In semi-arid Mediterranean areas, small grain aftermath stubble represents an important summer source of food for grazing flocks of small ruminants. Wheat stubble is a mediocre source of forage and flocks are grazed in summer under harsh conditions of temperature and air dustiness. However, stubble grazing procedures are changing, water and shading are more frequently available between grazing sessions (“improved management”), and the biological soundness of this ancestral practice needs to be re-visited. The present study was aimed at evaluating the cost in energy of “improved” wheat stubble grazing, compared with feeding a similar diet indoors. The intake of stubble was first quantitatively and qualitatively evaluated in Awassi sheep. Ewes consumed daily 980 ± 100 g day^− 1 of wheat stubble. Ewes were then housed and fed diets consisting of wheat hay, straw and grain formulated to be iso-energetic and iso-nitrogenous to diets consumed from wheat stubble. The average intake of ME was similar during the confinement and the pasture periods (6.4 ± 0.5 and 7.6 ± 0.8 MJ day^− 1of ME, respectively). During 2 days of each period, animals were fitted with external electrodes and data loggers of heart rate and skin temperature. Energy expenditure (EE) was calculated from oxygen consumption estimated as the product of heart beats rate measured for the two days by the amount of oxygen delivered to body tissues at each heart beat (O₂ pulse). The O₂ pulse was determined by simultaneously measurement of oxygen consumption and HR twice daily on two occasions, while grazing stubble and indoors. Energy expenditure and energy balance were not different in sheep while grazing wheat stubble (11.1 and − 3.5 MJ day^− 1) or fed indoors (11.1 and − 4.8 MJ day^− 1). Our data show that stubble did not cover nitrogen and energy requirements for maintenance, and that the cost of summer stubble grazing carried out under conditions described here is less than thought before.     

Formation of Polyamines in the Rumen of Goats During Growth

Ornithine decarboxylase (E.G. 4.1.1.17) and S-adenosylmethionine decarboxylase (E.G. 4.1.1.50) and their products putrescine, spermidine and spermine were estimated in the rumen liquid from 3 groups of growing kids and 23 adult goats. Polyamines were also estimated in the feedstuff used. Marked differences in polyamine synthesis in rumen liquid were observed between the different groups of kids. Two groups of kids growing up together with adult goats had at an age of 2–4 months a peak of a few days duration in enzyme activity as well as in polyamine concentration. In these groups ornithine decarboxylase activity reached maximal values of 158±79 s (n = 4) and 100 (66–117) (n = 3) nmol[¹⁴CO₂]/ml rumen liquid/h at an age of 120 and 77 days, respectively. The corresponding activity in rumen liquid from kids who were isolated from other animals was only about 1/10 of this value. By comparison ornithine decarboxylase activity in adult goats was 30.7±20 (n = 43) nmol[¹⁴CO]/ml/h.In rumen liquid from kids grown up together with adults, concentrations of the polyamines reached maximum at about the same time as ornithine decarboxylase activity. The mean maximal concentration of putrescine in the 2 groups was about 350 and 500 nmol/ml, while the corresponding value for spermidine was about 200 nmol/ml in both groups.Relatively constant and high concentration of polyamines were present in the feedstuff used. However, in growing kids the ruminai putrescine and spermidine concentration at times far exceeded those that could be accounted for by the estimated intake of polyamines by the food. The results therefore strongly indicate that polyamines are formed in considerable amounts in rumen content of kids during the phase of rapid growth. Results from a few experiments with calves also indicate that this may be true for cattle.polyamines; putrescine; spermidine; spermine; ornithine-decarboxylase; rumen liquid.     

Comparison of different levels and sources of microbial phytases

Phytases catalyse the hydrolysis of phytate rendering phosphorus (P) available for absorption. Endogenous plant phytases are to some extent present in cereals (depending on species and varieties) while microbial phytases are added to cereal based diets to increase the digestibility of phytate bound P. The present study compared two different microbial phytases. The basal diet was composed of wheat, barley, soybean and rapeseed meal without feed phosphate. The diet was initially expanded, pelleted at 90 °C and crumbled. Phytases were added at 250, 500 and 750 FTU kg^− 1 diet (Aspergillus niger; Phytase 1) and 375 and 750 FYT kg^− 1 diet (Peniophora lycii; Phytase 2). The experiment comprised 6 treatment groups of 6 pigs each kept in metabolism crates and fed one of the 5 test diets or a diet with no added microbial phytase. The diets were fed for 12 days, 5 days for adaptation and 7 days for total collection of faeces and urine. Phosphorus digestibility of the basal diet averaged 43% and increased to 55, 61 and 66% following addition of 250, 500 and 750 FTU/kg of Phytase 1 and 54 and 60% following addition of 375 and 750 FYT/kg of Phytase 2, respectively. In conclusion, equivalent effects were obtained when Phytase 2 was given at 1.5 times the doses of Phytase 1.     

Effects of crossbreeding indigenous Hair Goat with Saanen on carcass measurements and meat quality of kids under an intensive production system

The aim of study was to investigate the effect of genotype on carcass measurements and meat quality characteristics of purebred Hair Goat, Saanen × Hair Goat (F₁ and B₁) kids under an intensive production system. In total, 24 kids were slaughtered at the age of approximately 133 days. Kids were fattened for 56 days immediately after weaning. Hot carcass weights were 6.78, 7.61 and 7.02 kg and dressing percentages were 49.71, 49.27 and 48.78%, respectively ( P  > 0.05). Differences between genotypes for carcass measurements and indexes were not significant. Effect of genotype on pH measurements, drip loss, water holding capacity, cooking loss and Warner Bratzler shear force values were not significant. Meat lightness values at 0 h, 1 h and 1 day after cutting were higher in crossbred kids than Hair Goat kids ( P  < 0.05). Redness value was significantly higher in meat samples of Hair goat kids at 0 h, 1 h and 1 day measurements ( P  < 0.05). Kid genotype had no significant effect on meat sensory characteristics, except tenderness. Panelists gave lower scores for meat tenderness to F₁ and B₁ crosses compared to purebred Hair Goat kids. In conclusion, higher meat lightness values of crossbred kids, at particularly B₁ level, might have a positive effect on the consumer choices.     

Studies on the pathogenesis of bovine ephemeral fever in sentinel cattle. II. haematological and biochemical data

Twenty-two non-lactating dairy cattle from a sentinel herd previously described (St. George, 1985) were monitored daily during an outbreak of ephemeral fever. Nine developed clinical ephemeral fever between 25 December 1981 and 30 January 1982. There were no subclinical infections with bovine ephemeral fever virus in the group. There were, however, subclinical infections with CSIRO Village, Akabane, Aino, Tinaroo and Kimberley viruses as described by St. George et al. (1984). Six of the nine affected cattle showed a neutrophilia with a concurrent lymphopaenia on the day of pyrexia; however, the differential white cell profile had begun to change up to 24 h prior to leucocytosis. Serum carboxypeptidase values fell by 24 h following the febrile response. Plasma fibrinogen rose rapidly in all six cows. The peak concentration (15.6 ± 2.70 g l⁻¹) occurred 3 days after pyrexia with the highest individual increase being from 6.05 to 19.6 g l⁻¹. Plasma fibrinogen levels remained elevated for at least 7 days.

Serum calcium fell significantly during Day 1 of the disease, the mean decline being 0.22 ± 0.08 mmol l⁻¹. The greatest individual fall was from 2.33 to 1.92 mmol l⁻¹. None of the affected cattle showed any compensatory change in serum magnesium. There was no change in the normal values of creatinine, urea, γ-GT, AST and alkaline phosphatase. Bovine ephemeral fever virus was isolated from only four of the six cases, whereas specific antibody was detected in all cattle 3–4 days after recovery.