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1.
A three-year longitudinal study was conducted to evaluate effects of strategic anthelmintic treatment regimes on age at first lambing (AFL), weight at first lambing (WFL) and lambing interval (LI) of 356 communally grazed ewes and 675 lambs owned by 10 smallholder farmers in the central highlands of Ethiopia. The ewes were stratified by weight and randomly allocated to three treatment groups as untreated control (TG1), twice-dosed per year (TG2) for both nematodes and trematodes in mid-January and mid-June and four-time-dosed per year (TG3) in June for nematodes, in August–September for nematodes and adult Fasciola, in November–December and January–February for immature flukes. The fixed effect of anthelmintic treatments, parity, season and year of lambing on AFL and LI was evaluated. Mean ± standard error (SE) of lambing interval was 292 ± 3 days. Both anthelmintic treatments (TG2 and TG3) shortened (P < 0.01) LI by about 23 days compared to non-treated ewes (TG1). Season and year of lambing had a significant (P < 0.001) effect on LI. Mean ± SE of AFL and WFL was 598 ± 10 days and 17.2 ± 1.37 kg, respectively. Anthelmintic treatments and parity of dam of the ewe lamb did not affect AFL (P > 0.05). Birth and lambing seasons of the ewe lamb had significant (P < 0.05) effect on AFL. On the other hand, lambing season of the ewe had significant (P < 0.05) effect on WFL. Ewe lambs born in the long rains lambed more than 50 days earlier than the ewe lambs born in short rainy and dry seasons. Lambing occurred year-round with two peaks in August–September and December–January, each 5 months after the two rainy seasons. Anthelmintic treatment at the beginning of the two rainy seasons should improve reproductive performance of Menz ewe lambs in similar agro-ecology in the central highlands of Ethiopia. 相似文献
2.
Santiago-Moreno J López-Sebastián A del Campo A González-Bulnes A Picazo R Gómez-Brunet A 《Domestic animal endocrinology》2004,26(4):303-314
The aims of this study were to examine whether mouflons exposed to constant long and short day photoperiods are able to exhibit an annual cycle of hair growth and moult, and prolactin (PRL) secretion. Mouflon ewes were assigned to three groups of treatment. Ewes were maintained, either under natural photoperiod (control, n=9), or received a series of subcutaneous melatonin implants from December to April (n=8), or were exposed to a constant long day photoperiod (16-h light:8-h dark; 16L:8D) during 18 months (n=7). Blood was collected weekly to determine PRL concentrations, and hair samples were clipped weekly from the base of the neck to measure the length of predominant hair. Under constant long days and with melatonin implants, mouflons expressed an annual rhythm of PRL secretion, even though these treatments modified the times of rise or falling of PRL concentrations throughout the year. Hair growth initiation was almost coincident with the summer solstice in both control and melatonin-implanted mouflons but occurred two months earlier in long day hold mouflons (P<0.001). Long day hold mouflons had a lower hair growth rate than control and melatonin-implanted mouflons (P<0.001), and at the end of the experiment, a shorter hair length (3.4±0.24 cm; P<0.01) than control (4.3±0.17 cm), and melatonin-implanted mouflons (4.2±0.12 cm). Our data support the conclusion that in mouflon, an endogenous circannual rhythm of PRL secretion exists, and that the seasonal cycle of hair growth and moult appears to depend, at least in part, on circulating levels of PRL. 相似文献
3.
Linear models were developed and evaluated for the estimation of daily (24 h) and total lactation milk yield of dairy sheep from single morning (am) or evening (pm) milking records. A total of 22,908 individual test-day milk records of 5110 ewes of the Chios breed, raised in 46 flocks, were used. Depending on the model, different daily milk yield estimates were derived for each ewe, accounting for lactation number, stage of lactation, season of previous lambing and interval between successive milkings. Daily milk yield was also estimated from doubling the single am or pm record. Actual and estimated yields were compared using root mean square errors (RMSEs), mean absolute differences, an accuracy parameter defined as the ratio of the actual yield variance over the sum of the variances of actual yield and absolute difference, and the product moment correlation between estimated and actual yield. Results were validated on independent datasets. Linear models resulted in less biased and more accurate estimates of the daily milk yield than simply doubling the am or pm record. Root mean square errors decreased by 7-37% and the mean absolute difference was reduced by 1-4% of the average daily yield. Higher accuracy and correlation were obtained from linear model application than doubling. Total lactation milk yield was predicted based on actual daily yield and compared to predictions based on estimated daily yield from am or pm records, as well as directly on single milking records. Root mean square errors obtained when daily yield had been estimated with linear models were 26-35% lower compared to doubling the am or pm yield and 0-13% lower compared to estimating the total lactation yield directly from single milking records. Linear model application also resulted in lower mean absolute difference and higher accuracy and correlation than doubling the am or pm record. Recording the yield of a single milking (am or pm) instead of both can benefit milk recording by reducing its cost and increasing farmer participation. In this context, linear models developed in the present study can be used for the accurate estimation of daily (24 h) and total lactation milk yield from single milking records. 相似文献
4.
Effect of lactation stage, season and parity on milk cortisol concentration in Holstein cows 总被引:1,自引:0,他引:1
Michiru Fukasawa Hideharu Tsukada Takami Kosako Akihisa Yamada 《Livestock Science》2008,113(2-3):280-284
This experiment was designed (1) to study the effects of lactation stage, season, and parity on milk cortisol concentrations in Holstein cows, and (2) to elucidate the relationships between milk yield, quality, and milk cortisol concentration. Subjects of this study were 24 dairy cows kept in a free stall barn. Milk samples were taken on test day in May, August, November, and February. Data of milk yield, quality, and cortisol concentration were collected. Random effects of animals and fixed effects of lactation stage, test day, and parity on milk yield, quality, and cortisol concentration were analyzed using mixed models. We estimated the best linear unbiased prediction of each trait (BLUP) which was an animal-specific value. Correlation among milk yield, quality, and cortisol concentration was calculated using raw data and BLUP. The effect of the lactation stage on milk cortisol concentration was significant: the value observed in early lactation was higher than in other stages. However, the correlation between milk yield and cortisol concentration was low. The beginning of lactation might be a strong stressor for every cow. Calculated with raw data, milk cortisol concentration had respectively significant negative correlation with milk protein contents and solid not-fat contents. Calculated with BLUP, milk cortisol concentration showed a significant and negative correlation with milk protein contents. The lactation stage and milk protein contents should be considered for measurement of milk cortisol concentrations. 相似文献
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7.
Zieba DA Kirsz K Molik E Romanowicz K Wojtowicz AK 《Domestic animal endocrinology》2011,40(3):139-146
The pineal gland (PG) acts as a neuroendocrine transducer of daily and seasonal time through the nocturnal release of melatonin. Here, we examined the interaction of season, orexin, ghrelin, and leptin on melatonin secretion by pineal explants in short-term culture. Glands were collected after sunset from 12 ewes during long days (LD; April and May) and from an additional 12 ewes during short days (SD; October and November). Glands were transected sagittally into strips, with each equilibrated in 2.5 mL of Dulbecco's modified Eagle's medium for 60 min, followed by a 2-h incubation in control medium or medium containing orexin B (10 and 100 ng/mL), ghrelin (10 and 100 ng/mL), or 50 ng/mL of leptin. After a 3-h incubation, some PG explants treated previously with lower doses of orexin or ghrelin were challenged with 50 ng/mL of leptin and those treated with both doses of orexin were challenged with 300 nM of the β-agonist isoproterenol. One milliliter of medium was harvested and replaced from each well every 30 min. Treatment with the low dose of orexin during LD increased melatonin secretion about 110% (P<0.01); treatment with a high dose increased melatonin secretion about 47% (P<0.001). During the SD period, leptin stimulated (P < 0.05) melatonin secretion slightly compared with mean melatonin concentration in controls. However, together, orexin and leptin depressed (P<0.01) melatonin secretion. Both doses of ghrelin reduced (P < 0.01) melatonin concentration during the SD season compared with control culture. Addition of ghrelin and leptin to culture medium increased (P<0.01) melatonin concentration compared with ghrelin-treated culture and decreased melatonin concentration (P<0.01) compared with leptin-treated culture during SD. Isoproterenol stimulated (P<0.01) melatonin secretion compared with values observed during the pretreatment period. We conclude that orexigenic peptides (orexin B and ghrelin) and an anorectic peptide (leptin) affect PG directly. The responses of PG to those hormones depend on day length. Moreover, secretion of melatonin from the ovine PG is under an adrenergic regulation. 相似文献
8.
The objective of this study was to evaluate the effect of imposing different milking frequencies for the first 4 weeks of lactation on energy balance, blood metabolic profiles and reproductive performance. The milking frequencies imposed were once daily for the first 4 weeks of lactation and twice daily subsequently (X1), twice daily for the entire lactation (X2) and three times daily for the first 4 weeks of lactation and twice daily subsequently (X3). Two weeks prior to the first expected calving date, sixty-three multiparous, Holstein-Friesian cows, were allocated to treatments based on expected calving date, parity (lactation number = 2 and lactation number > 2), BCS and BW. Mean DMI was lower (P < 0.05) on X1 than X2 (15.7 and 17.1 kg/day) over the first 4 weeks of lactation, but DMI on X3 was not different to either. Milk yield was lower (P < 0.05) on X1 than on X2 and X3 (24.1, 31.9 and 31.4 kg/day) from weeks 1 to 4 and at week 10 of lactation (30.9, 33.9 and 33.7 kg/day) but was not different at week 20. Yield of milk constituents followed the same pattern as milk yield. Milking frequency had no significant effect on milk fat or protein concentration but milk lactose concentration was higher (P < 0.05) on X1 than on X2. Cows on X1 experienced less (P < 0.05) negative energy balance than those on X2 and X3 from weeks 1 to 4, with no difference between X2 and X3. Cows on X1 lost less BW (P < 0.05) from weeks 1 to 4 and lost less BCS up to day 73 of lactation than cows on X2 and X3. Plasma NEFA and BHB concentrations tended to be lower and plasma glucose tended to be higher on X1 than on X2 and X3 from weeks 1 to 4, while plasma insulin was higher on X1 than on X2 and X3 for the first 2 weeks of lactation. There was no difference between treatments in any reproductive performance variable measured. These results indicate that reduced milking frequency decreases milk yield and improves energy balance and metabolic status in early lactation. 相似文献
9.
Most studies on lactation curves only consider milk yield and describe a standard lactation curve of dairy cows, showing a peak or maximum daily yield occurring between 4 and 8 weeks after calving, followed by a daily decrease in milk yield until the cow is dried off. Wood's model is a widely used lactation curve function. Wood's model was fitted to test-day records of 95,405 lactations of parities lower than 5. Milk traits were milk yield (MY), fat percentage (F%), protein percentage (P%), fat yield (FY) and protein yield (PY), and the lactation curve was individually considered as a cluster of five linked curves. Milk trait and parity influence the goodness of fit of Wood's model. In 19.3% of the lactations, the shape of the MY, FY and PY curves follows the standard lactation curve while F% and P% have the reversed standard shape. The initial phase of lactation with the FY and PY curves contributes to the high variability of shapes. 相似文献
10.
Sixteen farms having an average lactation length between 14.9 and 18.9 days were selected based upon producers' willingness to keep records of production and lactation feed intake. Data contained 9162 subsequent litter-size records abstracted from computerized production information-system files and lactation feed-intake records. Two-way interactions between the associations of parity and lactation length, and parity and weaning-to-conception interval with subsequent litter size were found in the same statistical model. Subsequent litter size did not increase in parities 1 and 2 as lactation length increased – but subsequent litter size in sows of parities 3–6 increased. In only parity 1, sows with weaning-to-conception interval 6–12 days produced 0.5 fewer pigs at subsequent farrowing than those with weaning-to-conception interval 1–5 days. However, in multiparous sows, no difference in subsequent litter size was found between weaning-to-conception intervals 1–5 and 6–12 days. 相似文献
11.
D. OCallaghan T. Sweeney L. Taylor G. Roblot R. Wylde 《Domestic animal endocrinology》1999,16(4):149-217
The objective of this experiment was to develop a procedure for immunizing ewes against melatonin that would alter the effects of changing photoperiod on seasonal reproduction and prolactin secretion. Ewes were immunized against human serum albumin (HSA) as controls (n = 9) or a melatonin-human serum albumin conjugate (0.25 mg; n = 10) on December 14th (Day 0) and boosted 9 times. They were maintained on natural photoperiod and then transferred indoors and exposed to long days for 35 d, followed by short days for 146 d, long days for 93 d, and short days for a further 123 d. Antibody titers to melatonin (at a serum dilution of 1:1,250) were significantly higher in immunized ewes (27.3 ± 6.6%) than controls (0.7 ± 0.1%; P < 0.001). At the end of the experiment, antibody titers in immunized ewes (at dilution of 1:50) were higher in blood (43.7 ± 8.2%) than in cerebrospinal fluid (10.8 ± 3.9%; P < 0.05), and highly correlated (r2 = 0.746). Onset of the breeding season was advanced slightly after the second transfer from long to short days in immunized ewes (April 12 ± 3 d) compared with controls (April 25 ± 3 d; P < 0.05). Mean serum prolactin concentrations were lower (P < 0.05) in melatonin-immunized ewes compared with controls on natural photoperiod, after transfer from long to short days, during long days, and after the second transfer from long to short days. In conclusion, despite melatonin-immunization increasing antibody titers in blood and cerebrospinal fluid, and decreasing prolactin concentrations over much of the experiment, minimal effects on the timing of reproductive transitions in the ewes were evident. This discrepancy between the response of the prolactin and reproductive axes to melatonin immunization supports the hypothesis of a dual site of action of melatonin, with melatonin acting in the pituitary gland to mediate the effects of photoperiod on prolactin secretion and in the mediobasal hypothalamus to affect reproductive responses. 相似文献
12.
试验用营养酸模鲜茎叶替代奶牛部分精料观测其对泌乳牛的饲喂效果。试验共设三个试验组和一个对照组,其试验组营养政模的替代率分别为12.5%、25.0%及 37.5%,经三期 300天的饲喂,其结果为试验组比对照组头日产奶量分别高 0.96bd、2.25ab、2.67kg(P<0.01或 P<0.05),比对照组(CK)提高 7.7%、18.0%、21.3%;平均乳脂率分别提高 0.63A,0.35B,0.31B个百分点(P<0 .01或 P<0.05),比CK组提高17.3%、9.6%、8.5%。经济效益显著,适应性良好。试验证实,用营养酸模替代部分精料对提高奶牛泌乳量和改善牛奶品质及口感是有利的。 相似文献
13.
Background
Exogenous melatonin could induce cashmere growth. However, induced growth of cashmere fleece by melatonin implants cannot be combined with the typical growth, resulting in earlier shedding followed by another cycle of cashmere growth. To address this issue, we examine the effects on the cashmere yield, fibre characteristics, and the growth and reproductive performance of cashmere goats of planned administration of melatonin.Methods
Eighteen half-sib, female goats were assigned to two treatments (n = 9) including a control and a treatment where melatonin (2 mg/kg BW) was implanted at the end of April and end of June. Cashmere growth and shedding were observed for approximately 1 year following implantation. Fibre samples were collected monthly to determine cumulative cashmere length. Initiation and cessation dates for cashmere growth as well as the rate of cashmere growth were calculated. Cashmere yield, weight gain of dam, kidding date, litter size, and birth weight were also recorded.Results
Melatonin implantation increased cashmere yield by 34.5 % (control 553.7 g vs. melatonin 745.0 g; P < 0.01), cashmere length by 21.3 % (control 95.2 mm vs. melatonin 115.4 mm; P < 0.01), and decreased fibre diameter by 4.4 % (control 14.6 μm vs. melatonin 14.0 μm; P < 0.03). In melatonin-treated goats, the average initiation date was earlier than in control goats (May 18, 2013 vs. July 2, 2013; P < 0.01) but there was a similar cessation date (March 22, 2014 vs. March 27, 2014). Consequently, the duration of cashmere growth was longer in melatonin-treated goats than in control goats (307 vs.270 days; P < 0.01). The final BW, average daily gain, kidding date, litter size, and birth weight were not influenced by melatonin implantation.Conclusions
These data indicate that melatonin implantation (2 mg/kg BW) on two occasions (late April and June) increased cashmere yield by combining the induced growth of cashmere fleece with the typical growth and decreased the fibre diameter without changing dam growth rate or reproductive performance. 相似文献14.
15.
A study was conducted to determine the effects of season, farm location, and farm size on farm milk yield (FMY), average milk
yield per cow (AYC), milk fat, bacterial score, and bulk tank somatic cell count (BTSCC) of dairy farms in the central region
of Thailand. Farms were located in the districts of Kaeng Khoi, Muaklek, Pak Chong, and Wang Muang. Collection of data was
at the farm level; individual animal records were unavailable. A total of 967,110 daily farm milk yield, 58,575 milk fat and
bacterial score, and 24,109 BTSCC records from 1,034 farms were collected from July of 2003 to June of 2006. There were three
seasons: rainy, summer and winter. Farms were categorized into small, medium, and large according to the number of cows milked
per day. Results showed that FMY and AYC were higher (p <0.05) in winter and lower in the summer and rainy seasons. In addition, the majority of small size farms had higher (p < 0.05) AYC and milk fat values, and lower bacterial score and BTSCC values than medium and large size farms. 相似文献
16.
Interaction between salsolinol (SAL) and thyrotropin-releasing hormone (TRH) or dopamine (DA) on the secretion of prolactin in ruminants 总被引:2,自引:0,他引:2
Hashizume T Shida R Suzuki S Kasuya E Kuwayama H Suzuki H Oláh M Nagy GM 《Domestic animal endocrinology》2008,34(3):327-332
We have recently demonstrated that salsolinol (SAL), a dopamine (DA)-derived compound, is present in the posterior pituitary gland and is able to stimulate the release of prolactin (PRL) in ruminants. The aim of the present study was to clarify the effect that the interaction of SAL with thyrotropin-releasing hormone (TRH) or DA has on the secretion of PRL in ruminants. A single intravenous (i.v.) injection of SAL (5mg/kg body weight (b.w.)), TRH (1microg/kg b.w.), and SAL plus TRH significantly stimulated the release of PRL in goats (P<0.05). The cumulative response curve (area under the curve: AUC) during 120min was 1.53 and 1.47 times greater after the injection of SAL plus TRH than either SAL or TRH alone, respectively (P<0.05). A single i.v. injection of sulpiride (a DA receptor antagonist, 0.1mg/kg b.w.), sulpiride plus SAL (5mg/kg b.w.), and sulpiride plus TRH (1microg/kg b.w.) significantly stimulated the release of PRL in goats (P<0.05). The AUC of PRL during 120min was 2.12 and 1.78 times greater after the injection of sulpiride plus TRH than either sulpiride alone or sulpiride plus SAL, respectively (P<0.05). In cultured bovine anterior pituitary (AP) cells, SAL (10(-6)M), TRH (10(-8)M), and SAL plus TRH significantly increased the release of PRL (P<0.05), but the additive effect of SAL and TRH detected in vivo was not observed in vitro. In contrast, DA (10(-6)M) inhibited the TRH-, as well as SAL-induced PRL release in vitro. All together, these results clearly show that SAL can stimulate the release of PRL in ruminants. Furthermore, they also demonstrate that the additive effect of SAL and TRH on the release of PRL detected in vivo may not be mediated at the level of the AP, but that DA can overcome their releasing activity both in vivo and in vitro, confirming the dominant role of DA in the inhibitory regulation of PRL secretion in ruminants. 相似文献
17.
V. Sejian V. P. Maurya S. M. K. Naqvi D. Kumar A. Joshi 《Journal of animal physiology and animal nutrition》2010,94(2):154-161
This study was undertaken to study the influence of induced body condition score (BCS) differences on physiological response, productive and reproductive performance of Malpura ewes to optimise BCS for these ewes for maximising production making it economically viable. The study was conducted for a period of 1 year using thirty healthy Malpura ewes (2–4 year old). The animals were randomly divided and different BCS was induced within three groups named Group I (BCS 2.5; n = 10), Group II (BCS 3.0–3.5; n = 10) and Group III (BCS 4.0; n = 10). The parameters included in the study were allometric measurements, physiological response, wool yield and reproductive performance. BCS had a significant influence on allometric measurements, respiration rate and different reproductive parameters studied, while wool production differed significantly during spring and non‐significantly during autumn. The results revealed that the reproductive performance of Malpura ewes with a BCS of 3.0–3.5 was better in comparison with the groups with lower and higher BCS. It may be concluded from this study that an active management of breeding sheep flock to achieve a BCS of 3.0–3.5 may prove to result in an economically viable return from these flocks. 相似文献
18.
The aim of this work was to determine the effect of vacuum level of machine milking on milk yield, milk composition, milking efficiency, somatic cells counts (SCC), and teat end thickness of the Greek mountain breed Boutsiko ewes. Seventy two ewes after a suckling period of 45 ± 5 days were divided into three equal groups of 24 animals for level of milk production, prolificacy and lactation number. The overall experiment lasted 14 weeks. All groups were milked with a pulsation rate of 120/min, pulsator ratio of 50/50, and three vacuum levels of 38, 44 and 50 kPa, respectively, were applied for the three groups. Every two weeks, in a.m. and p.m. milking, measurements were taken for machine milk (MM) and machine stripped milk (MSM), milk composition, SCC, milk emission characteristics (only in a.m. milking) and teat end wall thickness (TEWT) before and after milking. The results have shown that the lower vacuum level of 38 kPa increased (P < 0.05) the percentage of machine milk (82.9%). There were no significant differences among the groups for milk composition, milk flow rate and SCC, but there was a difference in log SCC (P < 0.05) between 38 and 50 kPa. The teat end wall thickness was lower at the lower vacuum level (38 kPa) after milking, and increased (P < 0.001) as the vacuum level was raised to 50 kPa. The findings of this study suggest that with a lower vacuum level of 38 kPa, the ewes are milked better than those with 44 or 50 kPa. Also, the irritation of teats is considerably reduced, while no differences were seen regarding the health of the udder. 相似文献
19.
A study was carried out at the Kenya Agricultural Research Institute Mtwapa in Coastal lowland Kenya to evaluate the effects of supplementing Napier grass variety Bana (Pennisetum purpureum) with Clitoria ternatea (Clitoria), Gliricidia sepium (Gliricidia) and Mucuna pruriens (Mucuna) on feed intake, diet digestibility and milk yield of lactating Jersey cows. Clitoria and Mucuna were compared with Gliricidia; a widely studied nitrogen supplement to roughage-based diets in dairy rations in coastal Kenya. Twelve lactating Jersey cows in their mid lactation were assigned to four groups balanced for initial milk yield and live weight in a completely randomised design. One group was fed Napier grass ad libitum and 3 kg of maize bran daily (control). The remaining three groups were fed the control diet supplemented with 8 kg of fresh Clitoria, Gliricidia or Mucuna. Mucuna had lower CP (180 g kg− 1) concentration compared to Gliricidia (232 g kg− 1) and Clitoria (218 g kg− 1). Tannin concentration was higher in Gliricidia compared to the other legumes. They were however below the critical level of 6% hence were not expected to have any negative effect on animal performance. The total dry matter intake was not affected by legume supplementation (P > 0.05). Legume supplementation had no significant effect on organic and dry matter digestibilities (P > 0.05). Nitrogen supplementation (P < 0.05) increased daily milk yield by 20%, 27.5% and 32.5% for cows fed Gliricidia, Clitoria and Mucuna respectively. Results from this study show that Mucuna and Clitoria can give similar lactation performance to Gliricidia as nitrogen supplements Napier grass basal diet. 相似文献
20.
C. J. Ng’ang’a N. Maingi P. W. N. Kanyari W. K. Munyua 《Tropical animal health and production》2009,41(6):921-926
The effects of anthelmintics treatments in controlling gastrointestinal nematodes in breeding ewes in a semi-arid area of
Kenya were determined. The study carried out during two breeding seasons, between June 2000 and December 2001 where albendazole
was administered to groups of ewes, 2 weeks before mating, 3 weeks to lambing and mid lactation indicated significantly lower
nematode egg counts in treated than untreated groups of ewes. In the first breeding season, reduced rainfall resulted in pasture
scarcity and weight loss in both groups of ewes through out the gestation period, but losses were higher for the untreated
group. In the second season, both groups of ewes showed a steady increase in weight gain during the gestation period and post-partum,
but weight gains were higher in the treated group. In lambs, weight gains at 6 weeks were higher for treated ewes than control
groups, in both breeding seasons. The results of this trial indicate that anthelmintic treatments in breeding ewes in the
study area are beneficial in reducing gastrointestinal nematode infections and improving performance of the ewes and their
lambs. In addition to the treatments, breeding ewes should be given feed supplementation particularly during periods of pasture
scarcity. 相似文献