Effects of ecotrofin™ on milk yield,milk quality and serum biochemistry in lactating goats

A nutritional supplement (Ecotrofin™, by Vetoquinol Italia S.r.l) recommended in ruminants feeding to strengthen the physiological condition and improve digestive performance was tested in 20 pluriparae grazing goats divided in two groups (control and treated) to assess its possible effects on milk yield and quality and to assess eventual adverse effects. Animals from both groups also received 400 g/day of corn meal, and the treated group was supplemented with 20 g/head/day of the nutritional supplement. At the doses suggested by the manufacturer, despite a transient increase after 30 days of supplementation, Ecotrofin™ did not show significant effects on milk yield and, although some changes were found in the fatty acids profile, no significant improvement of MUFA and PUFA, as well as of omega-6:omega-3 ratio and CLA content were seen. Therefore, in our experimental conditions the supplementation of diet with Ecotrofin™ did not appear useful to improve goat's performance. A significant effect on kidney health markers (27 vs. 22.5 for urea and 0.83 vs. 0.76 for creatinine, p < 0.05) suggested a beneficial effect on renal function but, since levels fell in the normal ranges in both groups, such hypothesis would need further studies to be addressed.     

Detection of β2-agonists in milk replacer

₂-Agonist drugs may be illegally used as growth promoters for feedlot calves, when mixed into milk replacer immediately before feeding. To check for the presence of clenbuterol, salbutamol and terbutaline in such food, an analytical system was established using a screening method based on two commercial qualitative competitive ELISA tests, with antibodies raised against the arylamino group and thet-butyl group. The extraction procedure was based on precipitation of the milk samples with acetonitrile followed by filtration. The absence of any significant interference by other substances in the filtrate allowed detection of ₂-agonist drugs in spiked samples at the lowest concentration having a repartitioning effect (50 ppb for clenbuterol, mabuterol and terbutaline, 500 ppb for salbutamol). In view of a false positive response with tetracycline in milk samples and a cross-reaction between clenbuterol and mabuterol, an HPLC-MS technique was developed which, after extraction and purification of the samples with SPE C18 Polar Plus, was able to confirm the presence of these drugs. The good recovery after extraction (ranging from 84% to 90.2%) and the low detection limit with this method (250 ng/ml for clenbuterol, mabuterol and terbutaline, and 2.5 µg/ml for salbutamol) allowed easy confirmation and simultaneous detection of the four ₂-agonists at the lowest concentrations at which they are used in adulterated milk for calves.Abbreviations B optical density of the sample - B maximal optical density in total absence of competition - %B/B ₀ percentage of inhibition - ELISA enzyme-linked immunosorbent assay - EIA enzyme immunoassay - HPLC-MS high-performance liquid chromatography-mass spectrometry - m/z mass to charge ratio - ppb parts per billion - ppm parts per million - SPE solid-phase extraction     

Cobalt reduces the Δ⁹-desaturase index of sow milk

The main objective of this study was to examine if cobalt (Co) reduces Δ(9) -desaturase indices in milk and blood lipids in sows. The experimental design consisted of a repeated measurement consisting of a pre-treatment period of a minimum of 9 days, a treatment period of 5 days and a post-treatment period of 6 days. Experimental animals consisted of 10 lactating sows; five sows had an intramuscular injection of 59 mg Co diluted in 5 ml 0.9% saline solution twice a day, whereas the other five had an intramuscular injection of 5 ml 0.9% saline solution twice a day as a control. Milk Δ(9) -desaturase indices for cis-9 18:1, cis-9 16:1 and cis-9 14:1 were significantly reduced (p < 0.0001) as a result of the Co-treatment, contrasting with the plasma Δ(9) -desaturase indices, which were unaffected. Potential mechanisms explaining how Co might reduce milk Δ(9) -desaturase indices are discussed. Moreover, the toxicological level of Co and potential implications of using Co-ethylenediaminetetraacetic acid as a liquid marker in digestibility experiments are addressed.     

Integration of forage legumes with cereal crops. I. Effects of supplementation with graded levels of lablab hay on voluntary food intake,digestibility, milk yield and milk composition of crossbred cows fed maize–lablab stover or oats–vetch hay ad libitum

This study examined the effect of lablab hay supplementation of crossbred cows fed forages from cereal+forage legume intercropping (maize–lablab (ML) stover or oats–vetch (OV) hay) basal diets on feed intake, apparent digestibility, milk yield and milk composition of crossbred cows. Forty eight multiparous (parity 2–4) cows approximately 60 days prepartum and mean live weight 445 S.D.±57 kg at the beginning of the experiment were used in the study. The experiment lasted 200 days each cow, covering 60 days prepartum and 140 days postpartum. Lablab hay supplementation significantly (P<0.05) increased total DM intake and DM digestibility as compared with the unsupplemented diets but there was no significant (P>0.05) difference in total DM intake among the supplemented cows. Cows fed ML stover or OV hay supplemented with lablab hay had improved rumen environment as reflected in the rates of DM, OM, N and NDF degradation greater than 0.03 (i.e. 3%) per h. The degradation parameters; a, b, c and the effective degradability (ED) were higher (P<0.001) for lablab hay supplemented diets than for ML stover or OV hay basal forages fed alone. ML stover fed alone resulted into significantly (P<0.001) higher Ca, P, and Mg intake than OV hay fed alone while K intake was significantly (P<0.05) higher with OV hay. Increasing levels of lablab hay supplementation significantly (P<0.001) increased Ca, P and Mg intakes but did not significantly (P>0.05) affect K intake in both ML stover and OV hay diets. OV hay and ML stover basal forages fed to unsupplemented crossbred cows resulted into average milk yields of 6.82 and 8.25 kg/cow per day, respectively, over a lactation period of 140 days after calving. Supplementation with lablab hay significantly (P<0.001) increased milk yield of crossbred cows fed OV hay but for ML stover based diets, supplementation was only significant (P<0.05) at the lowest level (0.4% BW) of lablab offer. For ML stover based treatments, the highest daily milk yield (9.5 kg/head) was obtained at 0.4% of body weight (BW) lablab hay supplementation, while for OV hay treatments, the highest milk yield of 9.7 kg/head was obtained at 1.2% BW lablab hay supplementation. Mean concentrations of milk fat, protein and total solids were similar for both ML stover and OV hay diets fed alone but lablab hay supplementation did not significantly affect the concentration of milk components of cows fed both forages. It was concluded that for optimum milk production from crossbred cows fed ML stover and OV hay basal diets, supplementation should be at 0.52 and 0.85% of BW level of lablab hay, respectively. The lack of response to higher levels of lablab hay supplement despite the increased protein intake was interpreted as resulting from a deficit of dietary energy.     

Does milk yield reflect the level of welfare in dairy herds?

Under the assumption that milk yield may be reduced in herds with impaired welfare, the present study aimed at investigating whether milk yield could be used as a reliable indicator of welfare. In 125 commercial French dairy herds, the association between the welfare of the herd (evaluated using the Welfare Quality assessment protocol) and cow milk yield was investigated using linear mixed models. Positive associations were identified between milk yield and low aggressions between cows and good emotional state of the herd but there was a negative association with good health assessed through the occurrence of diseases and injuries. These opposite associations resulted in no association with the overall welfare of the herd. Milk yield should not therefore be used as an indicator of overall welfare.     

The effect of estrus synchronization treatments on somatic cell count of transitional-anestrus Awassi ewes’ milk

Fifty-three transitional-anestrus Awassi ewes, randomly assigned to three groups: fluorogestone acetate (FGA, n = 18), FGA-Prostaglandin (FGA-PGF, n = 18) and control (n = 17), were used to examine the effect of estrus synchronization protocols and steroid hormones concentrations on milk somatic cell count (SCC). Intravaginal FGA sponge was inserted for 13 days and 600 IU equine chorionic gonadotropin was administered for ewes of FGA and FGA-PGF groups at the time of sponge removal (day 0). In addition, 10 mg was administered to ewes of FGA-PGF group on day 0. Blood and milk samples were collected from all ewes on days -13, -6, 0, 1, 2, 7 and 14. Estradiol had significant positive correlation with the SCC during the periods of sponge insertion (P = 0.015, r = 0.235) and within two days (P = 0.063 r = 0.23) after sponge removal with no correlation with SCC of both udder halves during the luteal phase. Progesterone concentrations, on the other hand, had a significant positive correlation (P < 0.001; r = 0.420) with the SCC of both udder halves during the luteal phase of the experiment, but not during the periods of sponge insertion and expected estrus. SCC returned under the influence of endogenous progesterone on days 7 and 14 to pre-synchronization values. In conclusion, sheep milk SCC is affected significantly with induction of estrus and steroid hormones concentrations. However, peak SCC recorded during estrus was far below the upper limit of the current standard for normal milk. With the current standards for SCC of 1,000,000/ml as legal limit for abnormal milk control programs in sheep, estrus synchronization programs and the estrus status should not be considered when bulk-tank milk SCC is being investigated, but should be considered during the process of setting new standards.     

Prevalence of contagious mastitis pathogens in bulk tank milk in Québec

The objective of this study was to estimate the prevalence of mycoplasma, Staphylococcus aureus, and Streptococcus agalactiae in bulk tank milk (BTM) in Québec dairy herds. BTM was sampled 3 times a month in 117 randomly selected dairy herds. Samples were submitted for S. aureus, S. agalactiae, and mycoplasma and for direct mycoplasma detection by polymerase chain reaction (PCR). Mycoplasma spp. was identified at least once in 3 herds (2.6%) by primary culture and/or PCR and in 4 herds (3.4%) by enrichment culture and/or PCR. Staphylococcus aureus was isolated at least once in 99 (84.6%) and 112 (95.7%) herds in primary culture and after enrichment, respectively. Streptococcus agalactiae was isolated at least once in 9 (7.7%) and 10 (8.6%) herds in primary culture and after enrichment, respectively. Herd prevalence of mycoplasma was similar to that previously reported in Canada. Staphylococcus aureus is still by far the most important contagious mastitis pathogen.     

Serotypes of Streptococcus agalactiae cultured from dairy milk samples in Québec

Streptococcus agalactiae remains an important pathogen of dairy herds in Québec, but data about antigenic characteristics of this microorganism are sparse. This study was conducted to determine the variety of S. agalactiae serotypes in dairy herds in Québec. Two hundred and ninety-five isolates cultured from the milk of individual cows from 7 regions of Québec were serotyped. Sixty-two percent of the isolates were untypable. Among the 38% of typeable isolates, serotype III was found most frequently. In conclusion, the heterogeneity found among antigenic determinants of isolates from bovine milk suggests that an immunological method for the detection of S. agalactiae performed directly on bovine milk would not be a practical approach.     

Effects of oral supplementation with β-carotene on concentrations of β-carotene, vitamin A and α-tocopherol in plasma, colostrum and milk of mares and plasma of their foals and on fertility in mares

In this study, effects of oral β-carotene supplementation to mares (β-carotene group: 1000 mg/day, n = 15; control group: n = 15) from 2 weeks before foaling until 6 weeks thereafter on concentrations of β-carotene, vitamin A and α-tocopherol in plasma, colostrum and milk and plasma of their foals were determined. In addition, effects on fertility were studied. Beta-carotene concentrations increased in plasma and colostrum of β-carotene-supplemented mares compared to control mares (p < 0.05). In mares of both groups, β-carotene concentrations were higher in colostrum than in milk (p < 0.05). In foals, β-carotene concentrations increased with colostrum uptake and were higher in foals born to supplemented mares (p < 0.05; control group: 0.0003 ± 0.0002 μg/ml on day 0, 0.008 ± 0.0023 μg/ml on day 1; β-carotene group: 0.0005 ± 0.0003 μg/ml on day 0, 0.048 ± 0.018 μg/ml on day 1). Concentrations of vitamin A and α-tocopherol were higher in colostrum than in milk (p < 0.05) but did not differ between groups. Concentration of α-tocopherol in plasma of mares decreased over time and in foals, increased markedly within 4 days after birth. All but one mare (control group) showed oestrus within 2 weeks post-partum. Occurrence of oestrus did not differ between groups. More mares of the control group (7/7 vs. 5/12 in the β-carotene group) became pregnant after being bred in first post-partum oestrus (p < 0.05). In conclusion, β-carotene supplementation to mares increased β-carotene concentrations in plasma, colostrum and milk of mares and plasma of their foals but had no positive effects on fertility.     

The field detection of “inter-unit milk flow” in pipeline milking equipment

Abstract

Extract

There are many ways in which a milking machine can transmit infection from cow to cow. The immediate transfer of infection by the, teat-cups is obvious and the reduction of the effectiveness of this vector has been shown to reduce the incidence of mastitis (Wilkinson, 1965 Fell, L. R. and Richards, R J. 1970. A farm survey of milking machine performance, milking management and California Mastitis Test results. Aust. J. Dairy Tech., 25: 39–45.  [Google Scholar]). The change from bucket to pipeline milkers has been associated with an increase in the incidence of mastitis arid this has been attributed to the vacuum instability of the latter system. Fell and Richards (1970 Whittlestone, W. G. and Fell, L. R. 1969. Machine milking and mastitis. Proc. N.Z. Soc. Anim. Prod., 29: 22–25.  [Google Scholar]) have studied the relation-ship between machine stability and the level of somatic cells in milk, and Whittlestone and Fell (1969) Whittlestone, W. G., Leonard, R. O. and Brookbanks, E. O. 1970. Breakthrough in mastitis research. N.Z. Jl Agric., 120: 66–67.  [Google Scholar] have suggested that milk line vacuum instability could be associated with flow conditions that could give rise to the movement of potentially infected milk from the pipeline back into the clusters. This potential vector has been overlooked in the past but its presence, would clearly negate the beneficial effects of “back flushing”. A field study was therefore undertaken to estimate the frequency of occurrence of the “inter-unit flow” effect in pipeline systems, and Whittlestone et at. (1970) Wilkinson, F. C. 1965. Bovine mastitis control in Western Australia. Aust. vet. J., 41: 93–97.  [Google Scholar] found a high incidence of milk movement back to the cluster in high pipeline systems though the effect was not found amongst the limited number of low-line installations examined. Two types of “inter-unit flow” were detected: whole liquid movement which appeared as liquid milk in the measuring trap inserted between the cluster and the milk pipe, and “aerosol” which could only be detected by the use of plugs of cotton wool inserted in the test teat-cups. Evidence for the presence of “aerosol” and its role in transmitting infection within the cluster has been collected by A. Tolle (pers. comm.). This establishes the possibility that once infected milk has reached the cluster it can be transferred to the, end of the teat during milking.     

Occurrence of β-lactam-resistant Staphylococcus aureus in milk from primiparous dairy cows in the northeastern region of Brazil

Tropical Animal Health and Production - The objective of the current study was to isolate and identify Staphylococcus (S.) aureus strains resistant to beta-lactam antibiotics from primiparous...     

The effect of estrus synchronization treatment on somatic cell count of transitional-anestrus local-Damascus cross breed goats’ milk

An experiment was conducted to examine the effect of estrus synchronization protocols and steroid hormones concentrations on somatic cell count (SCC) of transitional-anestrus local-Damascus cross goats’ milk. Fifty-six goats (2–4-year old) were randomly assigned to three groups: fluorogestone acetate (FGA, n = 19), FGA-Prostaglandin (FGA-PGF, n = 19) and control (n = 18) groups. Intravaginal sponge containing 40 mg FGA was inserted for 13 days and an injection of 600 IU equine chorionic gonadotropin (eCG) was administered for goats of FGA and FGA-PGF groups at the time of sponge removal (day 0). In addition, goats of FGA-PGF group were injected with 10 mg dinoprost tromethamine () on day 0. Five fertile local-Damascus cross bucks were turned-in with all goats on day 0. Blood and milk samples were collected from all goats on days -13 (beginning of experiment), -6, 0, 1, 2, 7, 13 and 20 (end of the experiment). Four-year old and second-parity goats had significantly higher (p < 0.05) SCC of both udder halves than 2- and 3-year old and first-parity goats, respectively. There was a significant effect (p < 0.05) for treatment and number of kids born in the last kidding season on SCC of both udder halves. Neither estradiol nor progesterone concentrations were correlated with SCC in goats in this experiment. The SCC of both udder halves and left udder halves in goats of the control and FGA groups, respectively, increased significantly (p < 0.05) after sponge removal and buck introduction when compared with day 0, with no differences in the FGA-PGF group. This increase in SCC of the control and FGA groups coincided with peak estrus behavior. However, SCC was far below the upper limit of the current standard for normal milk. In conclusion, induction of estrus with progestagen based programs and buck introduction may cause temporary significant increase in SCC. However, the SCC values during this period of temporary increase were still in the range of acceptable values for normal milk. With the current standards for SCC of 1,000,000/ml as legal limit for abnormal milk control programs in goats, estrus synchronization programs and the estrus status should not be considered when bulk-tank milk SCC is being investigated.     

Genetic parameters for milk,growth, and reproductive traits in Guzerá cattle under tropical conditions

Tropical Animal Health and Production - This study aimed to estimate the genetic parameters of milk (305-day milk yield (MY305)), growth (weaning weight (WW), yearling weight (YW), and weight at...     

Dose dependent disposition of sulphadimidine and of its N4‐acetyl and hydroxy metabolites in plasma and milk of dairy cows

Summary

The disposition of sulphadimidine (SDM) and of its N₄‐acetyl (N₄‐SDM) and two hydroxyl metabolites, 6‐hydroxymethyl‐ (SCH₂OH) and 5‐hydroxyasulphadimidine (SOH), was studied in plasma and milk of dairy cows following intramuscular or intravenous administration of sulphadimididine‐33.3% at doses of 10, 45, 50, and 100 mg/kg. The main metabolite in plasma as well as in milk was SCH₂OH. The metabolite percentages, the final plasma elimination half‐lives, and the time of peak SDM concentrations in milk are presented for different dosages. The concentrations of SDM and its metabolites in milk ran parallel to those in plasma beyond4 hours p.i. The metabolite concentrations in plasma and milk were lower than those of the parent SDM. Sulphate and glucuronide metabolites could not be detected in milk.

At high doses (45 mg/kg or more) and SDM plasma concentrations exceeding 20 μg/ml, a capacity limited metabolism of SDM to SCH₂OH was noticed, viz, asteady state concentration of SCH₂OH and a biphasic elimination pattern for SDM and SCH,OH in plasma and milk.

The mean ultrafiltrate ratios of the milk to plasma concentrations with respect to SDM, SCH₂OH, SOH, and N₄‐SDM were: 0.69, 0.22, 020, and 0.63, respectively.

The total amount of SDM and its metabolites recovered from the milk after milking twice daily over the whole experimental time was less than 2% of the applied dose.

A bioassay method allowed of detecting qualitatively SDM concentrations exceeding 0.2 μg/ml in plasma or milk. Withholding times for edible tissues and milk are suggested.     

BSE: milk and risk potential?

A potential BSE risk for milk and milk products has to be evaluated by means of risk analysis, especially risk assessment. The 3rd element of risk assessment--hazard exposition--is of decisive significance. In 1997, the Scientific Steering Committee of the European Commission has categorized risk materials in 4 classes. Colostrum, milk and tissues of the mammary gland have been classified in category 4, i.e. "infectivity not detected". A secondary contamination of the milk can be excluded (living animals). However, the term "not detected" refers also to the low sensitivity of the mouse test, which has to be taken into consideration. Therefore, in 2000 investigations started in Great Britain to test milk fractions, especially the fraction of somatic cells, for the possible occurrence of prions, using newly developed and highly sensitive methods. Results can not be expected before 2003 at the earliest. In case prions would be detected, their biological activity has to be demonstrated in order to develop an appropriate risk assessment for the consumer. Investigations in Great Britain in the early nineties of the last century with suckling cows under practical conditions have shown no indications of a BSE transfer via the milk to the calves. Therefore, the statement of national and international organizations is still valid, that milk can be regarded safe according to the present state of scientific knowledge.