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11.
Interrelationships among parity, twinning, retained placenta, abortion, metritis, cystic ovaries, milk fever and postpartum reproductive events were investigated in Holstein cows in northeast Mexico. Data were from 6565 lacations from a large commercial dairy herd. Path analysis was used to model the direct and indirect effects of these variables. The risk of reproductive disorders in cows having a particular periparturient complication was assessed by odds ratio analysis. Milk fever was dropped out of the restricted model, mainly because of the low lactational incidence of this disease (0.5%).
The most important implied cause and effect relationships among the periparturient events were twinning causing retained placenta and retained placenta causing metritis (odds ratio = 5.2 and 4.7, respectively; P * 05). Excluding abortion, most reproductive disorders and twinning increased the days from parturition to first estrus (from 4.4 to 9.2 days), the days from parturition to conception (from 1.3 to 21.4 days), the services per conception (from 0.28 to 0.5) and the calving interval (from 14.7 to 21.3 days). Only in associations between retained placenta and reproductive parameters were the indirect components an important part of the total causal association. 相似文献
12.
R. Marín GalvÍn M. Ruiz Montoya M. J. Higuera R. Pérez J. M. Rodríguez Mellado 《Water, air, and soil pollution》2005,165(1-4):347-364
Electrochemistry can be a valuable instrument to preserve the aquatic environment, first, by elucidating the oxidation-reduction mechanisms of substances having toxicological potential at laboratory scale; second, by aiding through extrapolation to comprise the evolution and fate in the environment of these pollutants and, finally, by establishing the basis of some electrochemical deactivation processes at industrial scale. In this way, this paper deals on studies of a type of highly pollutant substances for the aquatic media such as the S-triazines. The first part of the paper is focused to show the electrochemical reduction behavior of some S-triazines (eleven compounds have been studied). Later, the probable consequences at natural scale of these electroreductive processes are evaluated. Thus, the electrochemical reduction of diluted solutions of s-triazine herbicides and parent compounds takes place at potentials of ?0.90 to ?1.20 V, at very acidic pH values. The electroreduction products generated in all cases have loss the aromaticity and, depending on the compound, the chlorine atom or the –SCH3 group. So, the resulting molecules present lower toxicity than the original compounds. For this reason, the electroreductive way can be an efficient option for the detoxification of S-triazine polluted waters. On the other hand, the natural deactivation of the s-triazines present in natural waters, in addition to the conventional photooxidative route taking place in well illuminated and oxygenated waters, could take place through the reductive process when the waters are essentially anoxic, acidic, and rich in suspended materials. This natural reduction, moreover, could favour the later oxidation or metabolization of the byproducts emanating of the original plaguicides. Finally, the reduction of S-triazines, both forced (industrial water depuration via electrochemical reduction) and no forced (natural aquatic media) requires more negative redox potentials, that is, more reductive environments as the molecules become more complex. 相似文献
13.
Milk Yield of Holstein Cows Induced into Lactation Twice Consecutively and Lactation Curve Models Fitted to Artificial Lactations 
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下载免费PDF全文 Jesus Mellado Edgar Sepulveda Jose E Garcia Alvaro Rodriguez Maria A De Santiago Francisco G Veliz Miguel Mellado 《农业科学学报》2014,13(6):1349-1354
Nineteen multiparous barren Holstein cows were subjected to an induction of lactation protocol for 21 d administering estradiol cypionate (2 mg kg−1 of body weight (BW) d−1, on day 1 to 14), progesterone (0.10 mg kg−1 of BW, on day 1 to 7), flumethasone (0.03 mg kg−1 of BW, on day 18 to 20) and recombinant bovine somatotropin (rbST; 500 mg per cow, on day 1, 6, 16 and 21). At the end of lactation and with a minimum of a 2-mon dry period, the same cows were again hormonally induced into lactation. Cows in both lactations were not artificially inseminated, they were milked 3 times daily and received rbST throughout lactation. Mean accumulated milk yield at 305 d in milk (DIM) did not differ between the first and second induced lactations ((9 710 ±1 728) vs. (9 309±2 150) kg; mean±SD). Total milk yield ((12 707±3 406) vs. (12 306±4 218) kg; mean±SD) and lactation length ((405±100) vs. (410±91) d; mean±SD) were not different between the first and second induced lactations. In a second study, 15 empirical models including exponential, power law, yield-density, sigmoidal and miscellaneous models were compared for their suitability by modeling 12-mon (n=334), 18-mon (n=164) and 29-mon (n=22) lactation cycles of Holsteins cows induced into lactation and treated with rbST throughout the lactation. Hoerl (Y= ab1/xxc), Wood (Y=axb exp(cx)) and Dhanoa (Y=ax(bc)exp(cx)) models were equally suitable to describe 12-mon lactations. An exponential model with five parameters (Y=exp(a+bx+cd2+e/x)) showed the best fit for milk yield for 18-mon lactations. The rational model (Y=a+bx/1+cx+dx2) was found to produce the closest fit for 29-mon lactations. It was concluded that, with the protocol used in the present study, multiparous cows respond favorably to a second cycle of induced lactation, with milk yield similar to that experienced during the first cycle. Thus, dairy producers might be able to lengthen the productive life of infertile high producing cows with a renewal of artificial lactation, which would imply an overall reduction in voluntary culling of cows. Also, various equations used to describe the lactation curves demonstrated the potential for fitting monthly milk records of Holstein cows with prolonged lactations and induced hormonally into lactation. 相似文献
14.
Mellado M Véliz FG García JE De Santiago Á 《Tropical animal health and production》2012,44(3):389-394
Data from 82 kiddings from mixed-breed (native x dairy goats) goats reared on rangeland (n = 47) or confinement (n = 35) were used to determine the influence of various factors on length of labour, standing of newborn kids and time to first
suckling in pluriparous goats. Both groups were mated at the same time to bucks of the same genotype in February. During the
kidding time in July, the goats were monitored for 24 h in order to register parturition traits and kid birth weight and body
measurements. For all goats, blood samples were collected at parturition in order to establish the nutritional state of goats.
Grazing goats had lower body weight and body condition score (P < 0.01) than pen-fed goats, as well as lower values for some blood metabolites indicative of low body energy reserves. For
both grazing and pen-fed goats, the majority of kiddings (>93%) occurred during daylight hours. No kiddings were registered
from 2300 to 0500 hours. No effects of height at withers, thoracic circumference and sex of kids at birth were found to influence
length of labour. Labour was shorter (P < 0.01) for pen-fed does than grazing goats (10.6 ± 1.18 min vs. 15.4 ± 1.2 min; mean ± SD). The length of parturition was
considerably longer (P < 0.05) for twin-bearing does than for single-bearing does (16.6 ± 1.76 min vs. 11.2 ± 0.81 min, respectively). The interval
between parturition and standing of kids was shorter (P < 0.05) for kids from litters weighing >3.3 kg (entire litter) than kids from litters with <3.3 kg (22.7 ± 1.82 min vs. 31.1 ± 2.76 min).
Time to first suckling was longer (P < 0.05) for kids delivered from pen-fed does than kids from grazing does (57.8 ± 7.57 min vs. 42.9 ± 3.05 min). These results
confirm that, independently of type of production system (intensive or extensive), kiddings of does are concentrated during
daylight hours. These results also indicate that conformation of kids does not alter duration of labour, and that nutritional
stress of goats during gestation (extensive conditions) does not interfere with the neonate’s level of alertness and arousal. 相似文献
15.
Ulises Macías-Cruz Ricardo Vicente-Pérez Miguel Mellado Abelardo Correa-Calderón Cesar A. Meza-Herrera Leonel Avendaño-Reyes 《Tropical animal health and production》2017,49(7):1393-1400
To evaluate the effects of pre- and post-conception undernutrition (UN) on fetal and placental development at mid-gestation, 28 Katahdin × Pelibuey multiparous ewes were blocked by weight and assigned to the following four dietary treatments (n = 7 each): ewes fed 100% (control) or 60% of their nutritional requirements 30 days before mating (UNPre), 50 days after mating (UNPost) or during both periods (UNB). Four twin-bearing ewes were selected per treatment at day 50 post-conception and then slaughtered at day 75 of gestation to analyze their fetuses. Control fetuses were heavier (P < 0.05) than UNPost and UNB fetuses in 14.6 and 9.4%, respectively. Organ weights as percentage of the fetal weight (except for liver) and morphometric measurements (except for abdominal girth) were similar between control and UN fetuses (UNPre, UNPost, and UNB). Placental mass was heavier (P < 0.05) in control ewes than UNB ewes, but not relative to ewes of other treatments. The number of placentomes per ewe and placental efficiency were unaffected by UN treatments. Compared to control, only UNB ewes exhibited variations (P < 0.05) in the proportion of placentomes, specifically for type A (+13.8%) and B (?12.6%). Placentomes of type A and B had lower weight, length, and width of placentas in UNPost and UNB ewes than placentas of control ewes (P < 0.05). Overall results indicate that fetal and placental development of ewes carrying twins is mainly altered when nutritional restriction occurs simultaneously before conception and during the first third of pregnancy. 相似文献
16.
A digestion trial was conducted to estimate the potential contribution of the chaparral browse Quercus durata (leather oak) and Adenostoma fasciculatum (chamise) on intake and nutrient digestion in goats and sheep. Four wether Kiko goats (avg. wt. 22.9 kg) and four wether
Targhee sheep (avg. wt. 39.6 kg) were housed in metabolism cages. Alfalfa pellets were used as a dietary supplement. Digestibility
of the shrubs was measured by difference and metabolizable energy (ME) and ME intake (MEI) were calculated from digestibility
and plants intake values. Oak and chamise had low crude protein (CP) content (6.5 and 4.3% DM) and high content of extractable
condensed tannins (17.8 and 9.8% DM). In vitro organic matter digestibility (OMD) and ME for oak and chamise were 35.6 and
33.1% and 5.0 and 4.7 MJ/kg DM, respectively. In vivo OMD (calculated by difference with alfalfa) and MEI, for browse were
greater (P < 0.01) for goats fed chamise compared to sheep. In oak, OMD was similar for both animal species but MEI was greater (P < 0.01) for goats. Greater (P < 0.05) DM and CP intakes (per kg BW0.75) were observed for goats fed either oak or chamise compared with sheep. When an energy source was given as supplement, the
potential contribution of chamise and oak to total ME requirements for maintenance was about 58.3 and 60.4% in goats and about
17.1 and 32.9% in sheep, respectively. In consequence, metabolizable energy supplied by these shrubs may not be adequate for
maintenance when, during grazing, they are consumed in high proportions with other chaparral plants that may have lower nutritional
value than the alfalfa supplemented in this study. Under an appropriate supplementation program, goats could be more effective
than sheep to control fuel load in California chaparral, as they consume more chamise and leather oak and obtain more nutrients
from them. 相似文献
17.
Effect of body condition score of does and use of bucks subjected to added artificial light on estrus response of Alpine goats 总被引：1，自引：1，他引：0
Raymundo Rivas-Muñoz Evaristo Carrillo Rafael Rodriguez-Martinez Carlos Leyva Miguel Mellado Francisco Gerardo Véliz 《Tropical animal health and production》2010,42(6):1285-1289
The effects of body condition score of does and exposure to sexually active bucks after exposure to long-day artificial photoperiod
were examined in mature anovulatory French Alpine goat in Northern Mexico. In June, goats in good (2.3 ± 0.2, scale 1 to 4;
n = 10) or poor (1.6 ± 0.3; n = 10) body condition were exposed during 15 day to sexually active bucks, which had been exposed to long photoperiod (16:8-h
light–dark cycle, starting in December). A third group of goats in good body condition was exposed to bucks kept under the
natural photoperiod of this region (26° N). All goats in good body condition exposed to bucks treated with prolonged photoperiod
exhibited estrus behavior, whereas only 50% of the does in poor body condition showed estrous behavior during the 15-day buck
exposure. None of the does in good body condition showed estrus when exposed to bucks under natural photoperiod. These results
revealed that a good body condition is required for maximum estrus response in anestrous Alpine goats and that exposure of
bucks to long photoperiod in winter is essential for an adequate stimulus to reestablish estrus cycles in anovulatory Alpine
does in Northern Mexico. 相似文献
18.
Sánchez Thevenet P Jensen O Mellado I Torrecillas C Raso S Flores ME Minvielle MC Basualdo JA 《Veterinary parasitology》2003,117(4):263-269
We investigated the presence of intestinal parasites in canine feces collected from public squares in Comodoro Rivadavia, Chubut, Argentina (45 degrees S, 68 degrees W) and determined the persistence of Echinococcus granulosus eggs in those droppings under natural environmental conditions in that region. In the first experiment, we analyzed 163 fecal samples collected from urban squares during 8 months time and found parasitic elements in 46.6%. The presence of parasites was independent of the condition of the feces (fresh or dried; P>0.05). Parasites potentially pathogenic in man were present, such as Toxocara species (spp.), Taenia spp./Echinococcus spp., Uncinarias spp., and Entamoeba spp. In the second experiment, we analyzed two canine fecal samples contaminated with E. granulosus eggs, deposited for 41 months within the natural environment. These parasitic elements persisted during the entire study as attested by light microscopy and the ELISA coproantigen test. We propose the study of the presence of intestinal parasites in canine feces within the environment as a general strategy for identifying and monitoring areas of risk for canine-related zoonoses since we were able to demonstrate the persistence of E. granulosus eggs in deposited canine feces for over 3 years within the area studied. 相似文献
19.
Luna-Orozco JR Guillen-Muñoz JM De Santiago-Miramontes Mde L García JE Rodríguez-Martínez R Meza-Herrera CA Mellado M Véliz FG 《Tropical animal health and production》2012,44(1):71-75
The objective of this study was to evaluate the efficacy of treating sexually inactive bucks with artificial long photoperiod
or testosterone on the induction of estrus in anovulatory grazing goats. A total of 91 multiparous mixed-breed anestrous goats
were randomly assigned to one of three treatment groups: (1) joining with bucks subjected to 2.5 month of artificial long
days (16 h of light/day; n = 31), (2) joining with testosterone-treated bucks (n = 30), and (3) joining with untreated bucks (control; n = 30). There were no differences between the light-treated (100%) and testosterone-treated (93%) bucks in their ability to
induce estrus in anovulatory does. On the other hand, none of the goats in contact with control bucks exhibited estrus. The
interval from start of mating to estrus was shorter in goats with the light-treated bucks (37.9 ± 4.8 h) compared with does
in contact with testosterone-treated bucks (58.3 ± 8.7 h). The overall pregnancy rate in goats joined with light-treated,
testosterone-treated and control bucks was 84%, 77% and 0%, respectively, with no difference (P > 0.05) between the first two groups. Anogenital sniffing, approaches, mounting attempts, and mounts were highest (P < 0.01) in light-treated bucks and lowest in control bucks. It was concluded that testosterone-treated bucks and long-day-treated
bucks were equally effective in synchronizing estrus in anovulatory goats and resulted in similar levels of fertility. Given
that light-treated bucks are unviable in communal production systems of goats raised by resource-poor farmers, the sexual arousal of bucks with testosterone is a practical and reliable method to induce ovulation in anovulatory
goats in pastoral goat systems in hot environments. 相似文献
20.
Avendaño-Reyes Leonel Robinson Peter H. Hernández-Rivera Juan A. Correa-Calderón Abelardo López-López Ángel Mellado Miguel Macías-Cruz Ulises 《Tropical animal health and production》2020,52(3):1141-1148
A survey was completed to determine water use by small-scale dairy farms in Mexicali Valley of Mexico and to associate it with dairy production parameters. Mexicali Valley surrounds the capital city of the state Baja California, Mexicali. Sixty-one smallholders were interviewed in person in this rural area of northwestern Mexico. On average, small dairy holders had more than 20 years of experience and were ~ 55 years of age; people working on their farms are especially relatives. A low percentage was literate (20%), and they belong to a local dairy association. Milk yield/cow/year does not reach 4000 kg of milk and 75% of producers do not follow a defined management program for their cattle. Hand-milking is still practiced by 27% of the producers, and there is a general lack of infrastructure to maintain milk in a refrigerated state so that there is a very high risk of zoonotic diseases. Water use efficiency (WUE) was linearly correlated (P < 0.05) with total irrigated area, but not with animal production parameters. Regression equations constructed to explain WUE exhibited low adjustment, and WUE was not associated (P > 0.05) with milk yield. Small dairy producers in Mexicali Valley are in a generally poor situation with low water use practices; however, required more government support to increase their benefits from this livestock activity.
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