Microbiological quality of raw milk produced in Estonia

Aims: The microbial quality of farm bulk‐tank raw milk produced in Estonia during years 2004–2007 was investigated. Methods and Results: Bulk‐tank milk samples were analysed for lactic acid bacteria count (LABC), psychrotrophic bacteria count (PBC), aerobic spore‐forming bacteria count (ASFBC), total bacterial counts using BactoScan and somatic cell count (SCC) using Fossomatic. Randomly selected psychrotrophic isolates were subjected to 16S–23S PCR‐ribotyping. LABC remained below 10⁴ CFU ml^?1 in most samples, while psychrotrophic micro‐organisms dominated in 60% of farms. PBC ranged from 4·2 × 10² to 6·4 × 10⁴ CFU ml^?1, and ASFBC varied from 5 to 836 CFU ml^?1. Conclusions: In general, the microbiological quality of the farm bulk‐tank milk was good – more than 91% of samples contained <50 000 CFU ml^?1, and SCC in the majority of samples did not exceed the internationally recommended limits. Genus Pseudomonas spp. was the dominating spoilage flora with Pseudomonas fluorescens as the prevailing species. Significance and Impact of the Study: Specific bacterial groups (LABC, PBC and ASFBC), not analysed routinely by dairies, were determined in bulk‐tank raw milk of numerous dairy farms during 4‐year period. Based on the survey, dairy plants can better control their supply chains and select farms (milk) for the production of specific products, i.e. milk with low PBC and high LABC for cheesemaking.     

Improving productivity of Malpura breed by crossbreeding with prolific Garole sheep in India

Garole, a prolific small sized sheep breed of India was introduced in the Mutton Project of the Institute during 1997 to explore the possibility of incorporating fecundity gene into Malpura (M) sheep of semi-arid region of Rajasthan. The data on reproduction and production traits of M and Garole × Malpura (GM) half-breds was used in the study to assess the improvement in evolved crossbred stock. The overall percent gain in prolificacy in GM was 52.38, which increased to 75.73 in third parity. The GM compared to M ewes also weaned more lambs per ewe lambed (1 versus 1.41). The lambing rate averaged 91.75 and 148.21% in M and GM ewes, respectively. The twin lambing percentage was only 4.71% in M flock while; it reached up to 51.10% in GM. Moreover, 5.72% of GM ewes produced triplets also. The genetic group non-significantly affect ewe efficiency (EE), but GM produced 3.3% more total lambs weight per ewe lambed at weaning and 6.15% more total lamb weight per ewe lambed at 6-month of age. The body weights at different ages of GM half-breds were lower (P < 0.01) compared to contemporary M lambs. The parity of ewes significantly affects body weight from birth weight to 12-month of age. The survivability of GM half-breds was almost at par with the local M sheep. Results revealed that the fecundity genes responsible for increasing prolificacy have been incorporated into the GM and it might prove a valuable germplasm towards evolving a new prolific strain of sheep. The crossing of Garole with M increased the ewe efficiency.     

Bimodal milk flow and overmilking in dairy cattle: risk factors and consequences

To maximise the return on capital invested in the milking parlour, the largest number of cows should be milked gently and completely in the shortest possible time. Bimodal milk flow and overmilking negatively influence the efficiency of the milk removal process and teat health. This observational study had the objective of investigating the prevalence of bimodal milk flow and overmilking, determining which individual and farm-related variables are associated with these occurrences, and determining the association of overmilking and bimodal milk flow with milk yield and with short- and long-term teat changes. Twenty-one farms were visited once during the study period, wherein the milking routine was timed, the teat condition was assessed, and dynamic evaluation of the milking vacuum was performed. A total of 606 vacuum graphic records were obtained, with an average of 29 ± 3 records per farm, in order to indirectly evaluate the milk flow and thus determine the occurrence of bimodal milking and overmilking time. The average percentage of bimodality per farm was 41.7%. The median overmilking time was 59 seconds, and on average, 78.3% of the cows in a herd were overmilked longer than 30 seconds. An association was found at cow level between the occurrence of bimodal milk flow and days in milk, the total stimulation time, parity, and the preparation lag time. The increase in the mean total stimulation time and the number of passes during preparation were associated with a decrease in the proportion of bimodality in the herd. Parity, reattachment of the milking unit and milking in manual mode were associated with an increase in overmilking time of an individual cow. The presence of a clogged air bleed hole in the claw and the reduction of the cluster removal milk flow threshold were associated with an increase in the herd’s median overmilking time. The average milk flow decreased with the increase in overmilking time and with the occurrence of bimodal milk flow. An association was also found between the occurrence of bimodal milk flow and decreased milk yield. A mean of 78.4% of cows per farm had short-term teat changes in at least one teat, and 33.6% of evaluated cows per farm displayed at least one teat with hyperkeratosis. These results emphasise the association of bimodality and overmilking on milking efficiency and reinforce the importance of the milkers’ actions and the functioning of the milking parlour for its prevention.     

Genetic parameters affecting 180-days standardised milk yield, test-day milk yield and lactation length in Spanish Assaf (Assaf.E) dairy sheep

A total of 42,197 records of test-day milk yield (TDY) and 7654 lactations from 3854 individuals belonging to the Spanish Assaf (Assaf.E) breed were analysed using univariate and multivariate models to estimate genetic parameters affecting TDY, total milk yield standardised to 180 days (MY₁₈₀) and lactation length (LL) in order to asses their possibilities of use in the selection scheme of the Assaf.E population. Estimates of h² were, in general, on the lower limit of those usually reported for the three analysed traits. Estimates of heritability for MY₁₈₀ varied from 0.131 to 0.177. Estimates of h² for LL and TDY were consistent regardless the estimation model being of, roughly, 5% and 10%, respectively. The estimates for the permanent environmental effect (c²) of TDY were consistently the same (0.27–0.28) regardless the fitted model whilst they showed large differences for LL and MY₁₈₀. Genetic correlations were always positive and high ranging from 0.792 for the pair LL-TDY to 0.999 for the pair MY₁₈₀-TDY. Correlations between permanent environmental effects were even higher ranging from 0.932 for the pair LL-MY₁₈₀ and 0.999 for the pair MY₁₈₀-TDY. The advantages of using TDY as selection criterion in the Assaf.E improvement scheme are discussed.     

Diffusion of precision livestock farming technologies in dairy cattle farms

The rising global demand for animal products and the growing public concerns about the environment and animal welfare require dairy farms to improve their efficiency and apply more sustainable farming systems. Precision Livestock Farming (PLF) could represent a valuable support in addressing these challenges. In recent years, dairy farms have been modernising and introducing new sensors and automatic systems for managing the herd. However, the diffusion of new technologies in Italian dairy farms is still limited and farmers are reluctant to invest in precision systems. The aim of the study was to investigate the presence of PLF tools in Italian dairy farms, the motivations, benefits and limits of technological investments from the farmers’ point of view and the factors affecting the diffusion of technology. From November 2020 to June 2021, an online questionnaire was distributed and 52 responses were obtained. About 79% of the farms were located in Lombardy. The more represented milking system was the conventional milking parlour (73%), followed by automatic milking (19%). The average age of respondents was quite low: 35% of them was less than 40 years old and more than 50% was between 40 and 60. Statistical analyses were performed to evaluate the effects of different factors on the presence of technology at farm. The age of the farmer, the milk production level and the presence of an automatic milking system influenced the technological level of the farm. Precision systems that provide information on animal activity for the management of reproduction and on milk yield and flow are the most popular and are considered among the most useful. Management of reproduction and milk production are the areas where farmers appear to show interest for future investments as well. Younger farmers appear to have implemented more PLF systems than older ones, and they show a propensity to invest in latest generation precision tools. Farmers seem to have a growing interest in PLF, but some limits have been identified: the investment costs, followed by the lack of time to check information from sensor systems and the difficulty in data interpretation. As PLF technologies can play an important role in the development of sustainable, animal-friendly and efficient livestock production, further improvements and efforts are necessary to increase the propensity to PLF of dairy farmers. Results can be useful in the Italian context but also in other countries where dairy farming is rapidly intensifying but PLF is encountering resistance.     

Microbiological quality of bottled water in Greece

microbiological quality of the water produced by 38 bottling plants in Greece between 1987 and 1992 is presented and discussed. The presence of Pseudomonas spp. is also considered.     

Microbiological analysis of composts produced on South Carolina poultry farms

Aims: The purpose of this study was to determine whether the methods used in compost operations of small and medium‐sized poultry forms resulted in the production of an amendment free of foodborne pathogens. Methods and Results: Nine compost heaps on five South Carolina poultry farms were surveyed at different stages of the composting process. Compost samples were analysed for coliforms and enriched for Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes. The waste materials and composting practices differed among the surveyed farms. On two farms, new materials were added to heaps that had previously completed the active composting phase. Five compost heaps did not reach an internal temperature of 55°C, and c. 62% of all internal samples in the first composting phase contained moisture contents <40%. Escherichia coli was detected in 63% of the surface samples (n = 38) and 9·8% of the internal samples (n = 82) from the first composting phase, as compared with 16·7% of the surface samples (n = 12) and 0% internal samples (n = 24) from the second composting phase. Salmonella was detected in 26 and 6·1% of all surface and internal samples collected from heaps in the first composting phase, respectively, but was absent in all compost samples undergoing a second composting phase. The predominant Salmonella serotypes were Thompson, Montevideo and Anatum. Neither E. coli O157:H7 nor L. monocytogenes was detected in any of the samples. Conclusions: Our results indicate that the conditions at the compost surface are suitable for pathogen survival, and the complete composting process can result in the elimination of pathogens in poultry wastes. Significance and Impact of the Study: This research provides information regarding the effectiveness of the composting practices and microbiological quality of poultry compost produced by small‐ and medium‐sized farms. Ensuring the safety of compost that may be applied to soils should be an integral part of preharvest food safety programme.     

Detection of early pregnancy-specific proteins in Holstein milk

Bovine pregnancy is commonly diagnosed by rectal palpation or ultrasonography and changes in progesterone concentration. To determine a simpler and less expensive diagnostic method, we sought to identify early pregnancy-specific proteins in bovine milk by comparing samples collected from pregnant and non-pregnant Holstein cattle. Of the 600-700 protein spots visible on 2-DE gel images, 39 were differentially expressed in milk from pregnant and non-pregnant cattle. Antibodies generated against synthetic peptides of milk whey proteins expressed specifically during pregnancy were used to confirm protein expression patterns. Western blot analysis showed that the levels of expression of lactoferrin (lactotransferrin) and alpha1G T-type calcium channel subunit (alpha-1G) were higher in samples from pregnant than non-pregnant cattle. These findings suggest that assays for pregnancy-specific milk proteins may be used to diagnose pregnancy in cattle.     

Production costs,economic viability,and risks associated with compost bedded pack,freestall, and drylot systems in dairy farms

The adoption of intensive production systems, such as compost bedded pack (CB) and freestall (FS), has increased recently in tropical regions, mainly replacing the drylot system (DL). Thus, our objectives were to compare production costs, economic outcomes, and risk of dairy operations in CB, FS, and DL systems. We collected data from 2 181 Brazilian farms over 120 consecutive months; 960 farms (144 CB, 133 FS, and 683 DL) met our selection criteria. All costs were modeled for two animal production categories: milking cows and non-milking animals. We used a regression model that included linear and quadratic parameters, and we added the production system as a fixed variable for all parameters tested with this model. Consultant, year, herd, and herd × system interaction were included in the model as random variables. Further, we simulated annual technical and economic indexes per farm. In addition, we developed a risk analysis to measure the probability of negative profit of the farms based on a 14-year historical series of milk prices. All production costs were affected by the system. Feed, medicine, sundry, and labor costs per farm per year were greater in DL farms when milk yield (MY) was greater than 3 500 L/day. The variables such as milk yield, assets per liter, asset turnover rate, return on assets, operational profit, profit per cow, and per liter of milk variables were greater in CB and FS with high MY (>3 000 L/day). Nonetheless, DL had the greatest economic indexes with a lower MY (<3 000 L/day), lower operating costs, and greater economic outcomes. The risk analysis indicated that the probability of negative profit (risk) was reduced for CB and FS as MY increased, but DL had the lowest risk with low MY levels. In conclusion, we suggest DL as the most attractive system for farms with MY between 150 and 3 000 L of milk/day as the DL had the lowest risk and the greatest profit in this production scale. Despite similar outcomes for CB and FS in most of the farms, the profit per cow ($/year), assets turnover rate (%), risk (%) and expected profit ($/L) analysis indicated that CB could be recommended for farms with MY greater than 3 200 L of milk/day, whereas based on risk (%) and expected profit ($/L), FS would be the most profitable system in dairies producing more than 8 000 L of milk/day per farm.     

A landscape‐scale model for optimal management of sheep grazingin the Magellanic steppe

Abstract. Effective management of rangelands requires the development of landscape‐scale models for predicting spatial and temporal variability of forage. In the Magellanic tussock steppes, as in other cold‐temperate regions, grazing capacity is dependent on the winter season. To develop a management tool for the region, we analysed links between winter forage availability, weather, stocking rate and vegetation structure. We studied four paddocks over five years with a range of stocking rates from 0 to 1.53 sheep.ha^‐1. We sampled forb and non‐tussock graminoid biomass, vegetation structure and faecal pellet abundance at the end of each summer. Daily temperature and rainfall data were also recorded. A regression model explained the amount of winter forage as a positive function of graminoid cover, spring minimum temperature, annual precipitation and a negative function of dwarf shrub canopy, bare soil and stocking rate (R²= 0.59). Interactions of structural variables with precipitation and stocking rate were detected, indicating strong fluctuations of forage availability in lawn communities dominated by short graminoids. The most probable causes of this response would be higher utilisation and lack of canopy structure. Our results illustrate how maps of vegetation structure, obtainable from satellite images, with weather and stocking rate data could be used for predicting optimal stocking rates in large, heterogeneous sheep paddocks.ed.     

Effects of two levels of monoterpene blend on rumen fermentation, terpene and nutrient flows in the duodenum and milk production in dairy goats

Twenty-six Alpine and Saanen goats, 12 fitted with a rumen cannula and a T-type cannula in the duodenum, were used in a 6-week experiment on the effect of a monoterpene blend on rumen fermentation, duodenal terpene and nutrient flows, milk yield and composition. The monoterpene blend consisted of 45.2, 36.7, 16.0 and 2.2 mol/100 mol terpene for linalool, p-cymene, α-pinene and β-pinene, respectively. The four compounds were considered as good models of northwest Mediterranean sward terpenes and were supplied in the same proportions as in the spring diet of dairy goats in the Basilicata (Southern Apennine range, Italy). The goats were assigned to three experimental groups fed a total mixed ration with no terpene or with the monoterpene blend at two levels, 0.043 and 0.43 g/kg dry matter intake. Ruminal fermentation characteristics remained unchanged among groups. In average, the total volatile fatty acids (VFA) concentration was 89.0 mM and the proportions of acetate, propionate and butyrate were 66.4, 21.1 and 10.1 mol/100 mol VFA, with an acetate:propionate ratio of 3.19. In average, 0.0, 2.7, 3.5 and 23.5 mol/100 mol of the ingested amounts of linalool, α-pinene, p-cymene and β-pinene were recovered in the duodenum. The mean terpene composition of duodenal digesta was 11.7, 9.2 and 79.1 mol/100 mol terpene for p-cymene, α-pinene and β-pinene, differing markedly from the dietary blend in both supplemented groups. Apparent rumen digestibility of dry matter (0.40), of neutral detergent fibre (0.54), and of acid detergent fibre (0.45) was not affected by either level of terpene supplementation. Dry matter intake and milk production, milk fat content or milk fatty acid profile were not affected by terpenes. It is concluded that, because of extensive ruminal degradation of each terpene, the monoterpene blend had no effect on ruminal digestion of dietary constituents or on milk performance whatever the supplementation level.     

Predictive microbiology: Uses for assessing quality and safety of dairy products

Summary Predictive growth models can be used to predict the shelf-life of products at any point from processing to purchase and to assist manufacturers devise suitable preservation strategies that inhibit the growth of spoilage and pathogenic organisms to an acceptable extent. A number of spoilage models for raw and pasteurized milk and cottage cheese are presented. In most fermented dairy products, the vigorous metabolic activity, of starter cultures prevents the growth of pathogens which limits the value of predictive models. Such modeling does however have application, particularly with respect to temperature abuse, in products such as pasteurized milk and cream where the perceived naturalness of the product prevents the use of chemical preservatives. Two models describing the growth ofListeria monocytogenes are presented. It must be remembered that it is not sufficient to observe that a model appears to work: it is important to know why it works which emphasizes the need for continued fundamental studies on the physiology of microorganisms to underpin the more applied aspects of modeling research.     

Acoustic sensing and signal processing techniques for monitoring milk fouling cleaning operations

Large resource investments are necessary in order to minimize the limiting problems arising from food industrial intensive productivity. One of the most challenging concerns is the cleaning status uncertainty among heat transfer areas in dairy heat exchangers, since the effectiveness of this process cannot be easily validated. The present study aimed to develop a low‐power ultrasound sensing method for monitoring the removal of milk fouling deposits along cleaning processes inside an experimental plate heat exchanger structure, connected to a milk piping unit. For that purpose, signal processing, namely acoustic feature extraction, over different wave patterns combined with artificial neural network techniques was used. Measurements were taken in pulse‐echo mode with a handmade 4 MHz ultrasound transducer. While fouling deposits having initial average thickness values of 250 μm (34.5 ± 4.5 mg/cm²) were removed, the acoustic transmissivity increased. Results showed that the signal features follow the expected trends in both, clean and fouled cases, within right guess detection accuracies above 80%. Therefore, when calibrated well, this could be a very sensitive and noninvasive technique for material characterization, as well as a suitable validation method for industrial cleaning cycle operation optimization that could significantly reduce the associated costs.     

Genetic and non-genetic factors associated with milking order in lactating dairy cows

The ability to rapidly identify temporal deviations of an animal from its norm will be important in the management of individual cows in large herds. Furthermore, predictors of genetic merit for especially health traits are useful to augment the accuracy of selection, and thus genetic gain, in breeding programs. The objective of this study was to estimate the repeatability of milking order and to quantify the contribution of differences in additive genetic variation to phenotypic differences (i.e., heritability). The data used in this study included 9813 herd milk recording test-day records with time of milking from 85,532 cows in 1143 herds across an 8-year period. Milking order was available for both morning and evening milking for each cow with, on average, 3.33 milk test-day records (i.e., 6.66 milking events) per lactation, and on average 1.62 lactations per cow. Variance components for milking order were estimated using animal linear mixed models; covariance components between milking order and milk yield, milk composition and somatic cell score (i.e., logarithm₁₀ somatic cell count) were estimated also using animal linear mixed models. The heritability of milking order was 0.20 indicating partial genetic control of milking order. The repeatability of milking order within test-day, within lactation, and across lactations was 0.63, 0.51, and 0.47, respectively. Milking order was positively (P < 0.001), but weakly, phenotypically correlated with milk yield (r = 0.04), and milk fat concentration (r = 0.01) and negatively (P < 0.001), but weakly, correlated with milk protein concentration (r = −0.02) and somatic cell score (r = −0.05). Milking order was positively (P < 0.05), although weakly, genetically correlated with milk yield (r = 0.07) and negatively (P < 0.05), but also weakly, genetically correlated with somatic cell score (r = −0.08). This study is the first to show a contribution of additive genetics to milking order in dairy cattle but the genetic correlation between milking order and somatic cell score was weak.     

Production performance and milk composition of dairy cows fed extruded canola seeds treated with or without lignosulfonate

Eight multiparous Holstein cows averaging 538 kg of body weight and 62 days in milk were used in a double 4 × 4 Latin square design with four 21-d experimental periods to determine the effects of feeding extruded versus non-extruded canola seed treated with, or without, 50 g/kg lignosulfonate on apparent whole tract digestibility, feed intake, milk production, milk composition, and milk fatty acid profile. Intake of dry matter (DM) and its components was similar among treatments. Extrusion had no effect on digestibility but decreased milk fat concentration. Lignosulfonate treatment of canola seeds decreased digestibility of DM and crude protein (CP). Milk production, milk concentrations of CP, lactose and total solids, and milk yields of CP and fat were similar among treatments. In general, there was no interaction between extrusion and lignosulfonate for milk fatty acid profile. Feeding extruded canola seeds increased milk fat concentration of trans11 18:1 to a greater extent without, than with, lignosulfonate treatment (150% versus 113%). Overall, it is clear that extrusion had more effects than lignosulfonate treatment on milk fatty acid profile, but changes were small and likely of little biological importance for human health.     

Microbiological composition of raw milk from selected farms in the Camembert region of Normandy

Raw milk from 27 farms was sampled over 6 months for listerias, salmonellas, Yersinia enterocolitica and campylobacters. Total bacterial counts and somatic cell counts were measured. Lactococci, lactobacilli, dextran-producing leuconostocs, Brevibacterium linens , yeasts and moulds, Staphylococcus aureus and other Micrococcaceae, Pseudomonas , coliforms, Escherichia coli , enterococci, Clostridium perfringens and spores of anaerobic lactate-fermenting bacteria were also counted. Pseudomonas (2000 cfu ml⁻¹), lactococci (760 cfu ml⁻¹) and Micrococcaceae (720 cfu ml⁻¹) were the most numerous groups. Lactic acid bacteria were detected in all samples. Coliforms were present in most samples, but 84% of samples had counts <100 cfu ml⁻¹. Staphylococcus aureus was detected in 62% of milks, the average count was 410 cfu ml⁻¹. About 80% of supplies had ≤10 E. coli cfu ml⁻¹ and all samples had 1 Cl. perfringens cfu ml⁻¹. Two of the tested milks were positive for salmonellas (2·9%), four were positive for Listeria monocytogenes (5·8%), 25 for Yersinia enterocolitica (36%) and one for campylobacters (1·4%).     

Effects of feeding supplemental palmitic acid (C16:0) on performance and milk fatty acid profile of lactating dairy cows under summer heat

The objective was to determine performance and milk fatty acid changes of high producing dairy cows in early lactation, under summer heat, by adding a supplemental rumen inert fat in the form of a saturated free fatty acid (856 g/kg C16:0/kg of total fatty acids) to the total mixed ration (TMR). Early lactation multiparous Holstein cows in two similar pens of 99 and 115 cows were used in a 2 × 2 Latin Square design experiment with 35 d periods during a period when daily high and low temperatures averaged 34.3 and 15.9 °C, the relative humidity averaged 51% and there were no rain events. The TMR was the same for both groups, consisting of approximately 435 g/kg forage and 565 g/kg concentrate, except that the vitamin/mineral premix had no added fat (control, C) or added fat (C16:0) at a level designed to deliver approximately 450 g/cow/d of supplemental fat if cows consumed 26.5 kg/d of dry matter (DM). The two TMR averaged 905 g/kg organic matter (OM), 318 g/kg neutral detergent fiber (aNDF), and 186 g/kg crude protein (CP). The ‘C’ TMR had 58 g/kg total fatty acids with an estimated net energy for lactation (NE_l) of 7.3 MJ/kg (DM), while the C16:0 TMR had 72 g/kg total fatty acids and 7.5 MJ/kg NE_l (DM). Whole tract digestibility of DM, OM, aNDF and CP tended (P<0.10) to increase, and that of fatty acids increased substantially (P<0.01), with C16:0 feeding, whereas, DM intake was not affected. Milk fat content decreased (P<0.01) with C16:0 feeding (37.5 versus 36.0 g/kg), whereas, true protein content tended (P=0.09) to increase. There was a tendency (P=0.07) for increased milk yield (36.69 versus 38.04 kg/d), while milk protein yield increased (P=0.03) with C16:0 supplementation (1.08 versus 1.13 kg/d). Milk fat yield was unaffected by treatment. Concentrations of short and medium chain milk fatty acids (C6:0–C15:0), decreased, or tended to decrease, with C16:0 addition (C13:0 and C15:0, P<0.10; all others, P≤0.05). The concentration of C16:0 increased (P<0.001) in milk triglycerides from cows fed C16:0 (27.10 versus 31.57 g/kg), the longer chain saturated fatty acids C17:0 and C18:0 decreased (P≤0.05) and other long chain unsaturated fatty acids were unaffected. Benefits of C16:0 feeding on cow productivity must be balanced against negative effects on the nutritive value of the milk (i.e., increased C16:0 in milk fatty acids) produced for human consumption. However, relatively low amounts of supplemental C16:0 (27.10 versus 31.57 g/kg in milk triglycerides for C and C16:0 supplemented cows, respectively) were actually secreted in milk, in spite of them being essentially fully digested in the digestive tract. Strategies to divide cows into production groups based on milk yield and/or milk fat proportions could further limit C16:0 secretion in milk. Supplemental dietary C16:0 may have positive effects on milk production that outweigh the negative health effects of the increased C16:0 content in the milk fat.     

Effect of fish oil and sunflower oil supplementation on milk conjugated linoleic acid content for grazing dairy cows

The objective of this study was to determine the effect of adding fish oil (FO) and sunflower oil (SFO) to grazing dairy cows’ diets on the temporal changes in milk conjugated linoleic acid (cis-9, trans-11 CLA). Sixteen Holstein cows were divided into two diet regimen groups. One group (CONT) was fed a basal diet (7.6 kg DM basis) plus 400 g animal fat. The other group (FOSFO) were fed a basal diet plus 100 g of FO and 300 g of SFO (FOSFO). The cows were milked twice a day and milk samples were collected every 3-day for a period of 21 days. Both groups grazed together on pasture ad libitum and fed treatment diets after the morning and afternoon milking. Milk production, milk fat percentages, milk fat yield, milk protein percentages, and milk protein yield were not affected (P>0.05) by treatment diets. The concentrations of cis-9 trans-11 CLA and vaccenic acid (VA) in milk fat were higher (P<0.05) for cows fed the FOSFO over 3 week of lipid supplementation. The concentration of cis-9 trans-11 CLA in milk fat reached maximum on day 3 with both diets and remained relatively constant thereafter. The concentration of VA in milk fat followed the same pattern of temporal changes as cis-9 trans-11 CLA. In conclusion, milk cis-9, trans-11 CLA and VA concentrations increased with FO and SFO supplementation compared with the CONT diet and the increase reached a plateau on day 3 of supplementation and remained relatively constant throughout the remainder of the study.     

Lamb and milk production of Awassi and East-Friesian sheep and their crosses under Mediterranean environment

Data on lambs born per ewe put to the ram (LB/EP), lambs born per ewe lambing (LB/EL), milk production through lactation and lactation length up to six lambings of 603 Awassi (A), East-Friesian (EF), A × EF (F1), F1 × F1 (F2), EF × F1 (1/4A), 1/4A × F1 (3/8A¹) and 3/8A¹ × 3/8A¹ (3/8A²) ewes bred in the same flock in the years 1956–1971 were analysed. The data were obtained from 2293 ewe-years, 1993 lambings and 1698 lactations. Genotype, age at lambing and sire within genotype had an (P < 0.05) effect on each trait. Effect of year of birth, genotype by age at lambing interaction and genotype by year of birth interaction were significant (P < 0.05) for milk production but not for lamb production. The effects of litter size on milk yield and lactation length were not significant. Least squares means (LSM) of LB/EP were highest in 3/8A² (1.48) and lowest in Awassi (0.98). LSMs of LB/EL were highest in EF (1.60), and lowest in Awassi (1.11). The LSMs of milk yield of A, F1, F2 and 3/8A² were similar, ranging from 223 to 248.1. The milk yield of EF was the lowest: only 161 1. The LSMs for lactation length were similar in all genotypes, about 198 days except for 1/4A and EF which had shorter (P < 0.05) lactations. The Awassi-transmitted effects were positive (P < 0.001) for lactation length and milk yield, and negative (P < 0.001) for LB/EL. Heterosis (P < 0.001) was found for LB/EL, milk yield and lactation length. Recombination effect was not significant for any trait.     

A suitable model for the utilization of Duddingtonia flagrans fungus in small-flock-size sheep farms

Effective alternatives to anthelmintic treatment of nematode parasite infections of sheep are required because of the high prevalence of drug resistance. Within this context, the nematode-trapping fungus Duddingtonia flagrans has become a valuable component of various integrated control strategies. Toward this objective, a small quantity of lyophilized D. flagrans chlamydospores (10⁶ spores per animal) was administered to sheep in a one-year plot study. Animals grazing on native pasture were divided into two homogeneous groups and were kept in 1-ha paddocks in the southern region of Brazil. The oral administration of chlamydospores led to a significant reduction (p < 0.05) in the number of nematode eggs per gram of feces and in the larval availability on herbage (difference of 37.6%) in comparison to the control group. Control animals needed to be dewormed three times during the experiment, whereas the fungus-treated animals maintained a low parasite load, independent of seasonal variation. Although D. flagrans cannot serve as a panacea for nematode parasite control of livestock, it represents a significant advance toward rationalizing the use of endoparasitic drugs in small animals.