Jaagsiekte sheep retrovirus is present at high concentration in lung fluid produced by ovine pulmonary adenocarcinoma-affected sheep and can survive for several weeks at ambient temperatures

Jaagsiekte sheep retrovirus (JSRV) causes a fatal lung cancer of sheep known as ovine pulmonary adenocarcinoma (OPA). OPA is a significant disease in many sheep-rearing countries and there is no effective method of control. A unique feature of OPA is the overproduction of fluid in the lung of affected animals. This lung fluid contains JSRV and provides a means of transmission through the inhalation of virus. In this study we demonstrated that lung fluid from different OPA cases contained between 10⁷ and 10¹⁰ copies of JSRV RNA per ml. Examination of JSRV RNA survival under conditions that mimic natural conditions suggested that intact JSRV virions may persist for several weeks in the environment. These are the first quantitative data on JSRV in lung fluid and provide valuable information for implementing appropriate biosecurity measures to control the spread of JSRV in the field.     

Colostrum production by primiparous and multiparous Holstein dairy cows and its usefulness as an estimator of full lactation milk yield

This study determined colostrum production of lactating primiparous and multiparous Holstein dairy cows, as well as the predictability of full lactation milk yield based upon this colostrum production. Holstein cows that calved between December 18, 2006 and December 24, 2007 (n = 134) had their first two post-partum milkings weighed and assayed for density. Cows then entered normal production groups and were assessed for milk yield and milk components every 4 or 5 weeks for the duration of their lactation. Primiparous cows produced less colostrum (10.6 versus 13.6 kg; P = 0.02) and density adjusted (DA) colostrum (5.2 versus 8.5 kg; P < 0.01), but there were no differences in estimated 305 day mature equivalent (305ME) milk production (mean = 13,654 kg) or lactation lengths (mean = 301 days) between parities. Colostrum and DA colostrum were poor estimators of subsequent 305ME milk production within primiparous cows (r² = 0.20 and 0.01 respectively) and multiparous cows (r² = 0.18 and 0.12 respectively). Colostrum production of these high producing cows was somewhat lower than expected, highly variable among cows within parity, higher for multiparous versus primiparous cows, and was not a good estimator of subsequent 305ME milk production.     

Linearity of eprinomectin pharmacokinetics in lactating dairy sheep following pour-on administration: excretion in milk and exposure of suckling lambs

Pharmacokinetics of eprinomectin (EPR) were studied in blood plasma and milk in two groups of six Istrian Pramenka dairy sheep and their suckling lambs following pour-on administration of EPR to ewes at dose levels of 0.5 and 1 mg/kg. Maximum concentration in plasma was 2.22 and 5.25 μg/l, and AUC was 13.6 and 33.7 μg day/l for the 0.5 and 1.0 mg/kg dose, respectively. These results indicate that drug exposure with a dose of 0.5 mg/kg, which is commonly used in cattle, may be subtherapeutic. The concentration time course in milk paralleled plasma concentrations. In the dose range studied, linear pharmacokinetics of EPR were demonstrated. Milk-to-plasma AUC ratio was 0.79 ± 0.12 and 1.12 ± 0.43; the fraction of dose recovered in milk was 0.037 ± 0.011 and 0.058 ± 0.027% for the low and high dose, respectively. Maximum residual levels in milk were below the maximum acceptable level of 20 μg/kg; however, EPR was detected in all samples investigated. Despite low permeability in milk, AUC in plasma of suckling lambs was between 20 and 30% of the AUC in plasma of ewes.     

中国荷斯坦牛初乳、常乳与乳房炎乳乳成分及理化性质的比较研究

本文旨在研究中国荷斯坦牛初乳、常乳及乳房炎乳乳成分及理化性质的差异。对扬州大学试验农牧场36头中国荷斯坦牛乳常规成分、乳密度和导电率进行了测定（其中初乳牛6头,产奶时间为产犊后1h到第8天,正常乳16头（无隐性乳房炎）,患不同程度隐性乳房炎奶牛14头）。结果表明,初乳随着泌乳时间的延长,乳蛋白率、SNF含量、密度和滴定酸度逐渐下降,乳脂率在波动中下降,导电率无明显变化规律;正常乳与隐性乳房炎乳乳脂率差异不显著（P〉0.05）,导电率差异显著（P〈0.05）,蛋白率、SNF、密度差异极显著（P〈0.01）。结果提示,随泌乳时间的延长,初乳中的理化指标的测量值呈下降趋势;乳汁导电率、SNF、密度、乳蛋白率和酸度可作为鉴别常乳和隐性乳房炎乳的指标。     

Relative contribution of colostrum from Maedi-Visna virus (MVV) infected ewes to MVV-seroprevalence in lambs

Maedi-visna virus (MVV) seroprevalence associated with consumption of colostrum from seropositive ewes was investigated in 276 housed lambs from birth to 300 days-old. At birth, lambs were allocated to five experimental groups according to the maternal MVV-serological status, source and mode of feeding colostrum (bovine or ovine and bottle fed or suckled from the dam) and type of horizontal MVV-exposure (raised with the dam or separately with other lambs). The risk of being seropositive at 300 days-old was associated with feeding ovine colostrum from seropositive ewes and increased with intake of bottle-fed ovine colostrum and was higher in lambs separated from their dams and raised with other experimental lambs compared to lambs raised with their dams. Approximately 75-87% of ELISA-positive results in lambs that had ovine colostrum was attributable to colostrum itself. However, approximately only 16% of naturally raised and 29-61% of bottle-fed ovine colostrum lambs were ELISA-positive as a result feeding ovine colostrum. These results confirm that ovine colostrum from seropositive ewes can be a major source of MVV but its overall contribution to seroprevalence in natural conditions is relatively low, and shows that horizontal MVV transmission can be an important source of infection in new-born lambs.     

Fat and cholesterol content and fatty acid composition of mares' colostrums and milk during five lactation months

In this study, the effect of the lactation stage on changes in the fat and cholesterol content and fatty acid composition of colostrum and milk of Wielkopolska mares' was investigated. Colostrum and milk samples from 10 lactating mares were collected at the beginning of lactation, on the 1st and 2nd day after foaling and then, starting from the first month of lactation, at 4 weeks' intervals up to the fifth month of lactation. Statistically significant differences were found between mares' colostrum and milk in the fat and cholesterol content as well as in the percentage rate of total fatty acids which occurred in significant quantities. Together with the lengthening of the lactation time, the content of fat and cholesterol in the mares' milk was observed to decrease. The authors also found a significant impact of the lactation period on changes in the ratio of polyenoic fatty acids from the n-6 to n-3 family. Bearing in mind the fat and cholesterol content and a more favourable (from the nutritional point of view) ratio of fatty acids from the family of n-6 to n-3, it is recommended to collect milk from mares in the 4th and 5th month of lactation.     

The inclusion of a daisy plant (Chrysanthemum coronarium) in dairy sheep diet: 2. Effect on the volatile fraction of milk and cheese

An experiment was undertaken to evaluate the effect on volatile fraction of milk and cheese of the inclusion of Chysanthemum coronarium (Asteracea) in the diet of grazing sheep. Plots sown either with a binary mixture consisting of Lolium rigidum Gaudin and Medicago polymorpha L. (LM) or a ternary mixture including the above species and C. coronarium L. (LMC) were grazed by groups of Sarda dairy ewes during May. This daisy plant contained several volatile compounds: the main were 1-methyl-4-(1-methylethylidene)-ciclohexene (terpinolene, 47%) and ethanol (36%). Among other volatile substances, terpenes such as -pinene, triciclene and camphene; cyclic and unsaturated hydrocarbons and esters were detected. In contrast no volatile fraction was found in both the grass and the legume.

The inclusion of C. coronarium in sheep diet affected the composition of volatile fraction of milk and cheese. In particular LMC milk and cheese, unlike the counterparts, were featured by the occurrence of terpenes such as terpinolene, triciclene, 3,7-dimethyl-1,6-octadiene, -pinene and camphene. A panel-test based on olfactory evaluation showed that the cheese obtained from sheep grazing the ternary mixture was distinguishable from that of counterparts grazing the grass-legume mixture (P < 0.05). To conclude this daisy plant can be regarded as a putative tracer of dairy sheep production system.     

The inclusion of a daisy plant (Chrysanthemum coronarium) in dairy sheep diet. 1: Effect on milk and cheese fatty acid composition with particular reference to C18:2 cis-9, trans-11

An experiment was carried out to evaluate the effect on milk and cheese fatty acid composition of the inclusion of Chrysanthemum coronarium L., (Asteracea) into dairy sheep diet. Plots sown either with a binary mixture consisting of Lolium rigidum Gaudin and Medicago polymorpha (LM) or a ternary mixture including the above species and C. coronarium were (LMC) grazed by groups of Sarda dairy ewes during May. The botanical composition of diet, as measured by n-alkane method, showed that 34% of LMC group diet consisted of Chrysanthemum flowers and leaves. Exposure of sheep to this non-conventional forage did not affect animal performance and milk composition (fat and casein, P > 0.05) but resulted in different milk and cheese fatty acid composition. In particular conjugated linoleic acid, vaccenic acid and linoleic acid were all higher in LMC than LM groups (P < 0.05). The probable main reason was the higher proportion of linoleic acid in Chrysanthemum forage and hence in LMC than LM diet.     

EEG changes in 4-week-old lambs in response to castration, tail docking and mulesing

OBJECTIVE: To interpret changes in EEG in relation to perceived pain of castration, mulesing and docking in lambs. DESIGN: Analysis of covariance (randomised block design) to determine the effects of treatment on eight bandwidths of the EEG frequency spectrum. PROCEDURE: Ninety-eight, 3- to 4-week-old lambs were subjected to one of seven treatments: castration, tail docking, mulesing, ear tagging, sham shearing, formalin injection (to induce lameness) and handling. EEG was recorded for 15 min before treatment, during treatment, and for 15 min after treatment. RESULTS: Consistently lower mean power values across all bandwidths of the EEG were found at the time of mulesing and docking than at handling and shearing (P < 0.01). Formalin injection resulted in lower power values than handling and shearing (P < 0.01). Castration had lower power values than handling and shearing. Similarly, for 15 min after treatment, mulesing and formalin injection had significantly lower power values than handling, shearing, ear tagging and castration (P < 0.05). CONCLUSION: The consistent effects associated with mulesing, docking and castration compared to handling, shearing and ear tagging suggest that mulesing at both the time of treatment and during 15 min after treatment results in a response that is similar to that of induced lameness. Docking and castration result in a response at the time of treatment that is similar to induced lameness and mulesing, but during 15 min after treatment is similar to the non-noxious control treatments. However, the depressing effects on the mean power values are the reverse of that anticipated from a previously developed pain model, highlighting the need for further research to develop this technology to evaluate pain associated with husbandry procedures.     

traT and CNF2 genes of Escherichia coli isolated from milk of healthy cows and sheep

The objectives of the present study were to isolate Escherichia coli from milk of apparently healthy cows and sheep and to investigate the presence of traT and cytotoxic necrotising factor-2 (CNF2) virulence genes by multiplex polymerase chain reaction (PCR). Milk samples collected from a total of 1028 apparently healthy ruminants (737 cows and 291 sheep) in eastern Turkey were streaked onto 5% sheep-blood agar. E. coli was isolated and identified by biochemical tests in 5.9% (61/1028) of milk samples. Correct amplification with the molecular length of 232 bp was obtained from all E. coli isolates by the species-specific PCR. The isolation rates of the agent were calculated to be 7.6% (56/737) in cows and 1.7% (5/291) in sheep. The difference between these proportions was statistically significant (p < 0.001). Multiplex PCR showed that traT and CNF2 genes were present in 62.3% and 6.6% of all isolates, respectively. Both genes were present in 16.4% of the isolates, with only 14.7% having neither gene.     

Responses to condensed tannins of flowering sulla (Hedysarum coronarium L.) grazed by dairy sheep: Part 2: Effects on milk fatty acid profile

A grazing experiment was undertaken to evaluate the effect of PEG supplementation on the fatty acid composition of milk from Sarda sheep grazing sulla. Twenty-four late-lactating sheep (12 per group), were paired and split into two groups: group control (CON), dosed daily with a quenching gun with 200 ml of water, and group PEG, dosed with 200 ml of a 50/50 w/v water solution of PEG. The sheep grazed two 0.8 ha plots of sulla under a rotational grazing scheme.The contents of c-9, t-11 CLA and t-11 C18:1 in milk fat were on average 40% higher (P < 0.01) in the PEG group than in the CON group. This can be explained by the higher biohydrogenation activity of ruminal bacteria in the PEG group, due to the partial inactivation of the tannins. Odd-branched chain fatty acids (OBCFA) were higher in PEG than in the control group (+ 20%; P < 0.01) and this confirms the hypothesis that tannin in sulla reduced ruminal microbial activity. Both linoleic (C18:2 c-9 c-12) and linolenic (C18:3 c-9 c-12 c-15) fatty acids were lower (P < 0.05) in milk from PEG, than in the CON-group (− 12% and − 30% for linoleic and linolenic acids, respectively). The mitigating effect on tannins of PEG increased the ratio of ω6/ω3 by 24%; (P < 0.01) and total trans FA content in milk by 20% (P < 0.01). In conclusion, condensed tannins in sulla at flowering are conducive to lower c-9, t-11 CLA and t-11 C18:1 but also lower total trans FA, ω6/ω3 ratio and higher linoleic and linolenic acid.     

Effect of feeding different levels of foliage from Cratylia argentea to creole dairy cows on intake, digestibility, milk production and milk composition

The effect of feeding different levels of foliage from Cratylia argentea (Desvaux) O. Kuntze to dairy cows on intake, digestibility, milk production and milk composition was studied in the dry tropics in Nicaragua. The treatments were sorghum silage ad libitum, either unsupplemented or supplemented with 2 kg or 3 kg of Cratylia on a dry matter (DM) basis. Six Bos indicus cows of the Creole Reyna breed, with a mean body weight of 386 (SD 19) kg were used in a replicated 3×3 Latin square design. Supplementation with Cratylia increased (p < 0.05) DM intake from 6.6 to 7.8 and 8.7 kg DM/day and milk production from 3.9 to 5.1 and 5.7 kg/day for sorghum silage alone and supplementation with 2 kg and 3 kg DM of Cratylia, respectively. Milk fat, total solids and crude protein and organoleptic characteristics (smell, taste and colour) were not significantly different among diets. The apparent digestibility coefficients of dry matter, organic matter, neutral detergent fibre and acid detergent fibre were not affected significantly by supplementation with Cratylia. However, crude protein (CP) digestibility increased (p < 0.05) in the diets supplemented with Cratylia compared to sorghum silage alone. In conclusion Cratylia given as a protein supplement to a low-quality diet improved DM intake and CP digestibility of the diet and increased milk production, but did not affect milk composition.     

Changes in fatty acid composition of milk from lactating dairy cows during transition to and from pasture

Five Holstein cows producing an average of 25.4 ± 6.4 kg/d and 347 ± 111 days in milk were used to study the changes in fatty acid composition in milk from lactating dairy cows during transition to and from pasture. The 45-d experiment was divided into 3 periods. During the first 2 d of the experiment (Period I), cows were fed a TMR diet containing 50% conserved forage and 50% grain. On day 3, cows were turned out to pasture and remained on all-pasture diet for 29 d (Period II). On day 32, cows were withdrawn from pasture and offered a TMR diet until day 45 (Period III). Milk yield was recorded daily, and milk fat content and fatty acid (FA) composition were determined daily for composite samples collected from a.m. and p.m. milkings. Data were analyzed using spline regression (H₀ = zero slope) to determine whether there was any change in the concentration of a particular fatty acid after a specific time or whether it had stabilized. Cows produced an average of 25.2 ± 5.5, 13.7 ± 5.6, and 12.1 ± 4.8 kg/d of milk with 3.6, 4.2, and 3.6% fat during pre-pasture, pasture, and post-pasture diets, respectively. The conjugated linoleic acid (CLA) content was 0.45% of total fat during pre-pasture, reached to a maximum of 2.53% on day 23 into pasture and plateaued thereafter for the period. Milk fat C_18:1 t-11 content was 2.89% of total fat during pre-pasture, reached a maximum of 7.95% after day 22 in pasture, and plateaued afterwards. The C_18:2 content declined gradually from pre-pasture to pasture diet with no further decrease observed after day 22, while C_18:3 content increased until day 7 on pasture. The post-pasture CLA content in milk fat reached a value similar to pre-pasture within 4 days after the cows were withdrawn from pasture. No change in other fatty acids was observed after day 7 once the cows were switched to post-pasture diet. In the present study, it took 23 days to establish the highest level of CLA in milk fat after turning cows out to pasture, whereas only 4 days were needed to bring it back to the original level once the cows were withdrawn from pasture. Other milk fatty acids were stabilized around day 23 after turning cows out to pasture and by day 7 after being withdrawn from pasture and put back on a TMR diet inside the barn.     

Effect of feeding different levels of foliage of Moringa oleifera to creole dairy cows on intake, digestibility, milk production and composition

An experiment was conducted in Nicaragua to determine the effect of feeding different levels of foliage from Moringa oleifera Lam (synonym: Moringa pterygosperma Gaertner) to dairy cows on intake, digestibility, milk production and milk composition. The treatments were: Brachiaria brizantha hay ad libitum, either unsupplemented or supplemented with 2 kg or 3 kg of Moringa on a dry matter (DM) basis. Six Bos indicus cows of the Creole Reyna breed, with a mean body weight of 394 ± 24 kg were used in a replicated 3 × 3 Latin square design. Supplementation with Moringa increased (P < 0.05) DM intake from 8.5 to 10.2 and 11.0 kg DM day^− 1 and milk production from 3.1 to 4.9 and 5.1 kg day^− 1 for B. brizantha hay only and supplementation with 2 kg and 3 kg DM of Moringa, respectively. Milk fat, total solids and crude protein and organoleptic characteristics, smell, taste and colour, were not significantly different between the diets. Apparent digestibility coefficients of DM, OM, CP, NDF and ADF increased (P < 0.05) in the diets supplemented with Moringa compared with B. brizantha hay alone. The results showed that the inclusion of Moringa as a protein supplement to low quality diets improved DM intake and digestibility of the diet and increased milk production but did not affect milk composition.     

A whole genome scan to map QTL for milk production traits and somatic cell score in Canadian Holstein bulls

The detection and mapping of genetic markers linked to quantitative trait loci (QTL) can be utilized to enhance genetic improvement of livestock populations. With the completion of the bovine genome sequence assembly, single nucleotide polymorphisms (SNP) assays spanning the whole bovine genome and research work on large scale identification, validation and analysis of genotypic variation in cattle has become possible. The objective of the present study was to perform a whole genome scan to identify and map QTL affecting milk production traits and somatic cell scores using linkage disequilibrium (LD) regression and 1536 SNP markers. Three and 18 SNP were found to be associated with only milk yield (MY) at a genome and chromosome wise significance (p < 0.05) level respectively. Among the 21 significant SNP, 16 were in a region reported to have QTL for MY in other dairy cattle populations and while the rest five were new QTL finding. Four SNP out of 21 are significant for the milk production traits (MY, fat yield, protein yield (PY), and milk contents) in the present study. Six and nine SNP were associated with PY at a genome and chromosome wise significant (p < 0.05) level respectively. Three and 17 SNP were found to be associated with FY at a genome and chromosome wise significant (p < 0.05) level. Five and seven SNP were mapped with somatic cell score at a genome and chromosome wise significant (p < 0.05) level respectively. The results of this study have revealed QTL for MY, PY, protein percentage, FY, fat percentage, somatic cell score and persistency of milk in the Canadian dairy cattle population. The chromosome regions identified in this study should be further investigated to potentially identify the causative mutations underlying the QTL.     

Early lactation dairy cows: Development of equations to predict intake and milk performance at grazing

The objectives of this study were to examine the effect of parity and days in milk (DIM) on dry matter intake (DMI) and actual milk yield (MY_Act) of grazing spring calving dairy cows in early lactation (< 100 DIM) and to develop equations to predict DMI and milk yield for grass based systems of milk production. A dataset containing 335 observations from 134 Holstein Friesian dairy cows was assembled from two early lactation grazing studies. Observations were available for primiparous (n = 130) and multiparous (n = 205) cows during periods of DMI measurement using the n-alkane technique. Animal performance was divided into two classes of DIM: less than 50 DIM (< 50 DIM) or between 51 and 100 DIM (> 50 DIM). Parity and DIM had a significant effect on grass DMI (GDMI), total DMI (TDMI), MY_Act and milk composition. TDMI increased with parity and DIM and ranged from 13.4 kg/cow per day (primiparous animals, < 50 DIM) to 20.1 kg/cow per day (multiparous animals, > 50 DIM). Actual MY increased with parity and decreased with DIM (range: 24.1 kg/cow per day (primiparous animals, > 50 DIM) to 33.0 kg/cow per day (multiparous animals, < 50 DIM)). Multiparous cows had greater bodyweight (BW) and lower BCS than primiparous cows. In the early lactation period a number of variables had a significant effect on GDMI, TDMI and milk yield. These predictor variables included BW, BCS, potential milk yield (MY_Pot), DIM, daily herbage allowance (DHA; > 4 cm), concentrate level and parity. The equations accounted for 79%, 83% and 86% of the variation in GDMI, TDMI and milk yield, respectively. Actual milk yield was always below the MY_Pot of the cows, the mean difference was 5.8 kg/cow per day. As DHA and concentrate level increased, the difference between MY_Act and MY_Pot reduced. This study supports the concept that immediately post-calving offering a grass based diet with a medium level of concentrate supplementation is sufficient to support high milk production in grazing dairy cows.     

Farming practices in Sweden related to feeding milk and colostrum from cows treated with antimicrobials to dairy calves

Background

Milk produced by cows in receipt of antimicrobial therapy may contain antimicrobial residues. Such antimicrobial-containing waste milk must be withdrawn from human consumption and is therefore sometimes used as calf feed. Unfortunately, this approach might promote selection of antimicrobial resistant bacteria in the calves’ intestinal microbiota. The objectives of this study were therefore to obtain an overview of waste milk feeding practices on Swedish dairy farms and to investigate if these practices were associated with certain farm characteristics. A representative group of 457 Swedish dairy farmers participated in a web-based survey with questions about the use of colostrum and milk from cows treated with antimicrobials at dry off or during lactation, respectively, as calf feed.

Results

Colostrum (milk from the first milking after calving) and transition milk (milk from the second milking to the fourth day after calving) from cows treated with antimicrobials at dry off was fed to calves on 89% and 85% of the farms in the study, respectively. When antimicrobial therapy was given to cows during lactation, 56% of the farms fed milk that was produced during the course of treatment to calves, whereas milk that was produced during the subsequent withdrawal period was fed to calves on 79% of the farms. Surveyed farmers were less prone to feed such milk if the antimicrobial therapy was due to mastitis than other infections. In Sweden, a majority of antimicrobial treatments during lactation are systemic administration of benzylpenicillin and thus, the bulk of waste milk in Sweden is likely to contain residues of this drug. Feeding waste milk to calves was more common on non-organic farms, and on farms located in Southern Sweden, and was less common on farms with cows housed in cold free stalls barns.

Conclusions

Waste milk that may contain antimicrobial residues is, at least occasionally, used as feed for calves on a majority of surveyed Swedish dairy farms. Future work should focus on the effect of waste milk feeding on the occurrence of antimicrobial resistant bacteria in the calves’ intestinal microbiota.     

Milk progesterone enzyme-linked immunosorbent assay as a tool to investigate ovarian cyclicity of water buffaloes in relation to body condition score and milk production

Background

Application of assisted reproductive technologies in buffaloes is limited to some extent by farmers’ inability to detect oestrus because of its poor expression. The present study aimed at investigating reliability of a milk progesterone enzyme-linked immunosorbent assay (ELISA) to assess the ovarian cyclicity during post partum, oestrus and post-breeding periods in water buffaloes.

Methods

Progesterone concentrations were measured by an ELISA in milk of 23 postpartum buffaloes in relation to oestrus, pregnancy, body condition score (BCS) and milk production. Two milk samples were taken at 10 days intervals, every month starting from day 30 and continued to day 150 post partum. BCS and milk production were recorded during sample collection. Milk samples from bred buffaloes were collected at Day 0 (day of breeding), Days 10–12 and Days 22–24. Defatted milk was preserved at −80°C until analysis. Pregnancy was confirmed by palpation per rectum on Days 70–90.

Results

Seventeen buffaloes had 47 ovulatory cycles, one to four in each, 13 were detected in oestrus once (28 % oestrus detection rate). Progesterone concentration ≥1 ng/ml in one of the two 10-day-interval milk samples reflected ovulation and corpus luteum formation. The intervals between calving to first luteal activity and to first detected oestrus varied from 41 to 123 days (n = 17) and 83 to 135 (n = 13) days, respectively. Eight buffaloes were bred in the course of the study and seven were found pregnant. These buffaloes had a progesterone profile of low (<1 ng/ml), high (≥ 1 ng/ml) and high (≥ 1 ng/ml) on Day 0, Days 10–12 and Days 22–24, respectively. Buffaloes cycling later in the postpartum period had fewer missed oestruses (P < 0.05). Buffaloes with a superior BCS had a shorter calving to oestrus interval and produced more milk (P < 0.05).

Conclusions

Milk progesterone ELISA is a reliable tool for monitoring ovarian cyclicity and good BCS may be an indicator of resuming cyclicity in water buffalo.     

Responses to condensed tannins of flowering sulla (Hedysarum coronarium L.) grazed by dairy sheep: Part 1: Effects on feeding behaviour, intake, diet digestibility and performance

The concentration of condensed tannins (CT) in sulla (Hedysarum coronarium L.) is moderate and overall regarded as beneficial. However, the intake of this forage can reduce diet digestibility, particularly during flowering phase. An experiment was run to assess the effect of CT on feeding behaviour, intake, diet digestibility and performance of dairy sheep rotationally grazing sulla at flowering phase. Twenty-four late-lactating sheep were blocked in two homogeneous groups and submitted to the following treatments: i) twice daily drenching with 200 g/day of a 50% w/v water solution of an anti-tannic substance, polyethylene glycol, group PEG; ii) twice daily drenching with 200 g/day of water, group CON (Control group). All the sheep rotationally grazed as a flock two sulla plots from April to June (8 weeks in total). Sward height, herbage mass, botanical and chemical composition of the herbage were measured at the beginning and the end of each grazing period. The feeding behaviour (3 sheep per group) was continuously monitored for 24 h in 6 weeks using the IGER behaviour recorders. Herbage DM intake (DMI), dietary DM digestibility (DMD) and apparent CP digestibility (CPD) were estimated on 8 sheep per group by the n-alkane method. On average, PEG group had longer total grazing (503 ± 12 vs 460 ± 12 min, P < 0.05) and eating time (425 ± 13 vs 391 ± 13 min, P < 0.07) than CON group. Moreover PEG group showed shorter inter-meal intervals (41 ± 3 vs 52 ± 3, min, P < 0.05) and higher number of daily meals than CT-exposed group (24 ± 1 vs 19 ± 1 min, P < 0.01). The herbage DMI was not affected by the treatment whereas DMD (74.60 ± 3.48 vs 58.30 ± 3.01%), and CPD (60.14 ± 4.83 vs 38.21 ± 4.83%) were both increased by PEG administration (P < 0.05) confirming the negative effect of sulla CT on these variables. Milk yield tended to be higher in PEG than CON (1331 ± 45 vs 1205 ± 59 ml, P < 0.11). Milk protein content was similar between groups while milk fat content was higher in CON than PEG ewes (6.61 ± 0.15 vs 6.11 ± 0.15%, P < 0.05), being the reverse true for milk urea (46.04 ± 1.27 vs 53.04 ± 0.76%, P < 0.001). To conclude, this experiment shows that when sulla is grazed at flowering as monoculture, dietary CT can exert negative effects on DM and CP apparent digestibility, in this study partially counterbalanced by a better metabolic utilisation of the nutrients up-taken.