Effects of thyroxine administration on the growth and survival of pike silverside (Chirostoma estor) juveniles     

Pamela Navarrete‐Ramírez  Aurea Orozco  Carlos Valverde‐R  Aurora Olvera  Elva Mayra Toledo‐Cuevas  LG Ross  CA Martínez‐Palacios 《Aquaculture Research》2011,42(6):808-814

The pike silverside has high aquaculture potential despite its slow growth. In this study, thyroxine (T₄) concentrations (0.13, 1.3 and 13 nM), a control with no hormonal supplement and a negative control containing 4.5 mM methimazole (MMI) were tested to evaluate the growth of this species. Juveniles (0.2 g) were exposed by immersion to these treatments for 8 h every second day for 120 days, and growth evaluations were performed monthly over the entire trial period. In addition, tissue samples from each treatment group were assayed for triiodothyronine (T₃) and deiodinase type 2 (D2) activity . The survival rates in all T₄ groups were high, and a significant increase in growth was observed (average of 58%). The MMI treatment caused an increase in mortality and a reduction in the final body weight compared with the control. T₄ administration did not affect the tissue levels of T₃, and it decreased muscular D2 activity only after 30 days of exposure. These results demonstrated that low concentrations of T₄ in the culture environment could improve the growth of this species without affecting tissue hormone levels. The technique may have useful applications for early‐stage aquaculture of this and other economically important species.  相似文献   

PRODUCTIVITY OF TROPICAL PASTURES     

J. Blydenstein  S. Louis  J. Toledo  A. Camargo 《Grass and Forage Science》1969,24(2):173-176

A 60-cow dairy herd was pastured throughout one year on unfertilized Guineagrass pastures in the humid tropical environment of Turrialba, Costa Rica. During part of this time, the producing herd was followed by dry cows in the rotation. Information was collected on monthly grazing pressure, forage digestibility and consumption, and milk yields. The average number of animal units (375 kg) over the year amounted to 1.06/ha. Forage consumption varied from 2.27–3.45 kg DM/ 100 kg liveweight, and consisted of 75% Guinea grass in the mixed pasture. Digestibility varied from 47.9–65.0%. Low consumption and digestibility coincided with the short drier season. Efficiency of DM conversion was about 13% with one high and one low value, interpreted as use and accumulation, respectively, of body reserves during those periods. Calculations of the N balance in Guineagrass pastures are given.  相似文献   

Comparison of worm control strategies in grazing sheep in Denmark.     

ME Boa  SM Thamsborg  AA Kassuku  HO B?gh 《Acta veterinaria Scandinavica》2001,42(1):57-69

Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed.  相似文献   

Mother–Offspring Interactions in Zebu Cattle     

MJR Paranhos da Costa  A Schmidek  LM Toledo 《Reproduction in domestic animals》2008,43(S2):213-216

The knowledge of the interaction between mother and offspring might contribute to enhance the welfare of the offspring and to improve the reproductive efficiency of the cow. However, there is still little information available about such interaction in some cattle breeds. A series of observational studies were set up, addressing the mother–offspring relationships of Nelore, Guzerat and Gyr cattle breeds. Firstly, the behaviour of cows and calves around the time of parturition was described, and then, the underlying factors that affect the calves' survival and development were studied. Special attention was given to the failure or delay in the first suckling. The results together are indicative of genetic variability for some studied variables, indicating the possibility of selection for calf vigour (using latency to stand up and latency to suckle as its indicators) and maternal ability (using percentage of time in contact with the calves), in spite of the estimates of heritability were low and presented high standard deviation for all variables. The individual variability in their suckling behaviour and the efficiency in first suckling cannot be explained by a single isolated underlying factor. By now, there are some results available, although there are many questions without answers. The field is still open for the development of future research.  相似文献   

Influence of Heat Stress on the Cortisol and Oxidant‐Antioxidants Balance During Oestrous Phase in Buffalo‐Cows (Bubalus bubalis): Thermo‐protective Role of Antioxidant Treatment     

GA Megahed  MM Anwar  SI Wasfy  ME Hammadeh 《Reproduction in domestic animals》2008,43(6):672-677

In the present study, the effect of heat stress, which is commonly observed in the animals of Upper Egypt area in summer, as well as the effect of antioxidant treatment as a thermo‐protective was examined. In this study, the animals (n = 120) were divided into winter group (n = 40, bred during winter) and summer group (n = 80, bred during summer) as well as, animals in the summer group were divided into first subgroup animals (n = 40) and injected with Viteselen intramuscularly (15 ml) twice weekly for 10 weeks and second subgroup animals (n = 40) were not treated (as control). Serum levels of progesterone (P4), oestradiol (E2), cortisol, superoxide dismutase (SOD), lipid peroxidase (LPO) and nitric oxide (NO) were measured. The pregnancy rate of all animals was detected rectally. The levels of oestradiol and the activity of the antioxidant SOD were decreased in serum of animals in behavioural oestrus during summer as compared with those in winter. During the same time period the levels of oxidants such as LPO and NO were increased in the serum of animals again in the phase of oestrus. In another group of animals treated by intramuscular injection with 15 ml viteselen (antioxidant) twice weekly for 6 weeks during hot months, the activities of serum SOD showed an increase and the levels of oxidants and cortisol decreased. Moreover, the levels of oestradiol were increased during the oestrous behaviour. The pregnancy rate was decreased in animals under heat stress and the pregnancy rate was enhanced dramatically when these animals received antioxidants during the heat stress. This means that the heat‐stress in Upper Egypt may affect the fertility of animals and pregnancy rate and this effect may be through an increased production of free radicals and decreased production of antioxidants as well as increased levels of cortisol. Treatment of animals or supplementation with antioxidants before the beginning of months of heat‐stress and also during the stress period may correct the infertility due to heat‐stress through the decrease in cortisol secretion and a decrease in the oxidative stress. These results resulted in an increase in pregnancy rate in treated animals.  相似文献   

Ovarian Cyclicity and Reproductive Performance of Holstein Cows Carrying the Mutation of Complex Vertebral Malformation in Japan     

ME Ghanem  N Isobe  H Kubota  T Suzuki  A Kasuga  M Nishibori 《Reproduction in domestic animals》2008,43(3):346-350

This study was carried out on 71 lactating Holstein Friesian cows to investigate the resumption of ovarian cyclicity postpartum and the reproductive performance in cows carrying the mutation of complex vertebral malformation (CVM) compared with control ones. The cows were distributed in two dairy farms in Hiroshima Prefecture, Western Japan. Blood samples were collected from the cows to detect carrier cows with CVM mutation. Furthermore, plasma samples were collected weekly after calving from control cows (n = 10) and CVM carrier cows (n = 10), until 10 weeks postpartum to investigate the day of first ovulation and the resumption of ovarian cyclicity postpartum. The reproductive parameters were investigated and compared with control and CVM carrier cows. Thirty‐six cows were diagnosed to be CVM carriers by DNA examination and confirmed later by DNA sequencing. The pedigree analysis of the carrier cows revealed that they were daughters of six types of CVM carrier semen that still was used in dairy farms in Western Japan. In terms of reproductive indices, there were no significant differences between the control and the CVM carrier cows on the day of the first ovulation postpartum and the interval from calving to first insemination. However, CVM carrier cows significantly required more inseminations per conception and showed a significantly longer period to conception and subsequent calving than control ones. In conclusion, the reproductive performance of the CVM carrier cows was lowered through conception failure that might indicate the occurrence of intra‐uterine mortality in those cows.  相似文献   

The effect of litter materials on broiler performance: a systematic review and meta-analysis     

T. D. S. D. Toledo  C. S. Pich  M. A. Dai Prá  F. Leivas Leite  E. Gonçalves Xavier 《British poultry science》2019,60(6):605-616

ABSTRACT

1. Divergence in outcomes from studies on the effects of litter materials on body weight, feed intake, feed conversion and mortality in broilers has led to a need for a meta-analysis to quantify their effects.

2. A systematic search of published quantitative research relating to wood shavings and alternative bedding litters was conducted using databases.

3. Means, standard deviations and sample sizes were extracted from each study. The response variables were analysed using the standardised mean difference (SMD, control treatment minus alternative litters).

4. The literature demonstrated that alternative materials have no impact on feed intake in broilers, compared to wood shavings (SMD = 0.064, 95% CI = ?0.101–0.229, P = 0.44).

5. There was a positive overall effect of wood shavings on body weight (SMD = 0.253, 95% CI = 0.073–0.433, P = 0.006), feed conversion (SMD = ?0.169, 95% CI = ?0.327 – ?0.012, P = 0.03) and mortality (SMD = ?1.069, 95% CI = ?1.983 – ?0.155, P = 0.02) of broilers, compared to other litter types.

6. Subgroup meta-analysis revealed that straw, when used as an alternative litter material to wood shavings, may be responsible for lower body weight (SMD = 0.654, 95% CI = 0.162–1.146, P = 0.009), worse feed conversion (SMD = ?0.487, 95% CI = ?0.828 – ?0.145, P = 0.005) and higher mortality rates of broilers (SMD = ?3.25, 95% CI = ?5.681 – ?0.819, P = 0.009). Rice husks impaired body weight compared to wood shavings (SMD = 0.535, 95% CI = 0.065–1.004, P = 0.02).

7. It was concluded that different litter types do not affect the broilers’ feed intake. Conversely, broilers kept on straw showed lower body weights, worse feed conversion and higher mortality rates, in comparison to wood shavings. Rice husks decreased body weight compared to wood shavings.  相似文献   

Challenges Facing Grasslands inthe Northern Great Plains and North Central Region     

John R. Hendrickson  Kevin K. Sedivec  David Toledo  Jeffrey Printz 《Herpetological Monographs》2019,41(1):23-29

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Effect of different mini‐volume colloid centrifugation configurations on flow cytometrically sorted sperm recovery efficiency and quality using a computer‐assisted semen analyzer          下载免费PDF全文

LB Ferré  JL Chitwood  C Fresno  HH Ortega  ME Kjelland  PJ Ross 《Reproduction in domestic animals》2018,53(1):26-33

Straws of sex‐sorted sperm are usually packaged at a low concentration (e.g., ~2.1 × 10⁶ sperm/ml) and cost significantly more than unsorted conventional semen from the same sire. In order to maximize the efficiency of using sex‐sorted sperm under in vitro fertilization conditions, the selection of an appropriate sperm separation technique is essential. In this study, the effect of using different silane‐coated silica colloid dilutions and layering configurations during centrifugation of sex‐sorted sperm was examined over an extended period of incubation time. Sperm recovery and viability after centrifugation using the colloid separation technique were measured along with several sperm motility parameters using CASA. For this purpose, frozen and thawed sex‐sorted sperm samples were centrifuged using mini‐volume single‐layer (40%, 60% and 80%) and mini‐volume two‐layer (45%/90%, 40%/80% and 30%/60%) separation configurations using PureSperm^®. A single layer of 40% PureSperm^® recovered significantly more sex‐sorted sperm (78.07% ± 2.28%) followed by a single layer of 80% PureSperm^® (68.43% ± 2.33%). The lowest sperm recovery was obtained using a two‐layer PureSperm^® dilution of 45%/90% (47.57% ± 2.33%). Single‐layer centrifugation recovered more sorted sperm (68.67% ± 1.74%) than two layer (53.74% ± 1.74%) (p < .0001). A single layer of 80% PureSperm^® exhibited the highest sorted sperm viability (72.01% ± 2.90%) after centrifugation (p < .05). The mini‐volume single layer of 80% PureSperm^® was determined to be an effective alternative to a two‐layer centrifugation configuration for sex‐sorted sperm selection. In addition, single‐layer colloid dilution of 80% performed either as well as or significantly outperformed the other treatments, as well as the control, with regard to motility (MOT) for all time periods of analysis.  相似文献   

Effect of hyperbaric,controlled atmosphere,and UV treatments on peach volatiles     

Dong Sik Yang  René R. Balandrán-Quintana  Carlos F. Ruiz  Romeo T. Toledo  Stanley J. Kays 《Postharvest Biology and Technology》2009,51(3):334-341

The effect of hyperbaric (HP) and controlled atmosphere (CA) storage and prestorage treatment with ultra violet (UV) radiation on the volatile chemistry of peach [Prunus persica (L.) Batsch] fruit was assessed. Peach volatiles were analyzed using a dynamic headspace system with Tenax trap, automated short path thermal desorption, and GC–MS. The composition of volatile compounds emanating from the fruit varied quantitatively and qualitatively with storage (4 weeks). A total of 65 volatiles were identified, 21 prior to storage and 59 after 4 weeks storage. Six of the prestorage volatiles were not found after storage. The concentration of total volatiles and esters, the highest relative proportion of primary classes increased 32.5- and 36.5-fold, respectively, during storage. Ethyl butanoate, ethyl hexanoate, and ethyl heptanoate contributed to peach aroma due to their low odor thresholds and high concentrations. Using a factorial design (2 × 2 × 2), the main effects [storage pressure (P), storage gas atmosphere (A), and UV pretreatment] and interactions (P × A, P × UV, A × UV, and P × A × UV) were determined. P contributed most to the concentration of total volatile compounds followed by A; HP and HP + CA with or without UV significantly reduced the concentration of total volatiles and esters. Prestorage UV irradiation treatment did not affect the emission of volatile compounds. Principal component analysis (PCA) using 59 volatile compounds emanating from stored fruit indicated a significant effect of P and A on the emission of volatiles that were divided into four treatment groups accounting for 67.5% of the total variance, i.e., AP + Air, AP + CA, HP + Air, and HP + CA. The PCA distribution indicated which compounds contributed most to differences in volatile pattern among treatments: ethyl (Z)-4-octenoate, ethyl heptanoate, ethyl octanoate, and decanal (AP + Air); 3-methylbutyl acetate, ethyl butanoate, ethyl hexanoate, and 2-methylbutanoate (HP + CA); nonanal and hexanal (AP + CA); and hexyl acetate (HP + Air).  相似文献