G. Annicchiarico

Effect of parity on milk yield, composition, somatic cell count, renneting parameters and bacteria counts of Comisana ewes

Twenty-four Comisana ewes, with no history of mastitis, were included in this study, with eight ewes each in parities 1, 2 and 3. Groups were separately penned on straw litter and ewes were individually checked for yield, composition, renneting properties and bacteriological characteristics of milk from January, when separated from their lambs (50+/-3 days after lambing), to May. Samples with more than 3.5x10(5) somatic cells/ml were cultured for mastitis related pathogens. Milk yield was not significantly affected by parity. The P3 ewes had significantly higher milk protein, casein and fat contents compared to the P1 and P2 ewes. The P3 ewes also had improved renneting ability of milk as compared to the P1 ewes. Quality of milk decreased with lower lactations. The milk of P1 ewes had significantly greater amounts of mesophilic bacteria than the P2 and P3 ewes, as well as higher concentrations of psychrotrophs and total coliforms in their milk with respect to the P3 ewes. Somatic cell counts in milk and the prevalence of subclinical mastitis were not changed by parity, although mastitis infection set in progressively earlier as the number of lactations decreased. These results suggest that ewes in first or second lactation have a less favourable milk secretion status in relation to mastitis than ewes with a higher number of lactations. Milk yield and quality of younger ewes may be improved by offering feed rations that take into account this reduced capacity to mobilise body reserves. Also, most scrupulous control of sanitation of housing, equipment and personnel is necessary.

Lambs prevented from suckling their mothers display behavioral, immune and endocrine disturbances.

The aim of the experiment was to assess the effects of either maternal deprivation or prevented suckling on lambs. Thirty Comisana lambs were assigned to a control dam-suckled group (DS) and two test groups of 10 each. Test lambs were maintained with their mothers 24 to 30 h after parturition and subsequently offered ewe milk from buckets: EM lambs were separated from their mothers, while EM+D animals were reared with their dams but suckling was denied by covering ewe udders with juta bags. Behavioral, immune and cortisol responses of lambs were assessed throughout the experiment. EM+D lambs spent less time (P<.001) on investigative behavior compared to the two other groups. When isolated in a novel environment, EM+D lambs exhibited a shorter duration of movement (P<.01) and a longer latency time compared to DS and EM lambs (P<.001 and P<.05, respectively) as well as a higher number of bleats (P<.01) than EM lambs. EM+D lambs also displayed higher (P<.001) plasma cortisol levels than the other two groups when isolated at 4 days of age. When subjected to discrimination tests, EM+D lambs spent less time near their companions (P<.01) than EM lambs and took a longer time to reach their pen mates (P<.01) than DS and EM lambs. EM+D lambs displayed reduced growth (P<.001) compared to DS animals during the 0-7 and 8-14-day periods. We conclude that frustration arising from maternal feeding deprivation results in altered endocrine and behavioral responses and reduced growth suggesting emotional disturbances of lambs.

Effect of stocking density on ewes' milk yield, udder health and microenvironment.

Three groups of 12 lactating Comisana ewes were housed in separate rooms of the same building that contained straw-bedded pens with total areas of 12, 18 and 24 m2. The ewes were assigned to groups with different stocking densities: high (HSD, 1 m2/animal), medium (MSD, 1.5 m2/animal) or low (LSD, 2 m2/animal). The LSD treatment resulted in lower air concentrations of total microorganisms and coliform bacteria than the other two. Ewes in the LSD group gave greater yields of milk, total protein and fat than those in the other two groups. LSD treatment increased milk casein content and improved clotting time and clot firmness. LSD also resulted in ewes giving milk with lower somatic cell counts and smaller concentrations of mesophiles, psychrotrophs and faecal coliforms than MSD and HSD. Subclinical mastitis occurred in three ewes of the MSD groups and four ewes of the HSD group, while no cases were recorded in the LSD group. These results indicate that stocking density is a critical factor in dairy sheep housing and suggest that a space allocation < 2 m2/animal may adversely affect the performance and health of the lactating ewe.

Relationship between cortisol response to stress and behavior, immune profile, and production performance of dairy ewes.

The existence of a relationship between cortisol levels, after an acute stress, and behavioral activities, immunological profile, and production performance in sheep was studied. An initial flock of 30 Comisana ewes was involved in the experiment, and each of the 30 ewes was individually subjected to an isolation test in a novel environment. Subsequently, from the initial flock, 2 groups of 8 Comisana ewes were each retrospectively selected, and the animals were divided, according to their cortisol concentration 10 min after the isolation test, into high cortisol (HC) ewes, having a peak of cortisol concentration >90 ng/mL (average: 119.3 ng/mL +/- 11.8), and low cortisol (LC) ewes having a peak of cortisol concentration <80 ng/mL (average: 52.4+/-11.8). During the isolation test, the behavior of each animal was video-recorded and behavioral activities were registered. Blood samples were collected before the isolation test, immediately after the test (10 min), and at 60, 120, 300 min, 24 h, and 48 h after the test to evaluate percentages of T-helper (CD4(+)) and T-cytotoxic (CD8(+)) cells, CD4(+)/CD8(+) ratio, and IL-1beta and IL-6 levels. The ewes were milked for 3 d after the isolation test to determine cortisol levels and IL-1beta and IL-6 concentrations in whey. Milk yield was recorded at each milking, and milk samples were analyzed for pH, nutritional parameters, renneting properties, and somatic cell count. During the isolation test, HC ewes exhibited a shorter duration of movement and fewer bleats than LC ewes. The average plasma IL-1beta concentration was higher in HC than in LC ewes. The average whey IL-1beta and IL-6 concentrations were higher in whey from HC ewes than in LC ewes. A positive correlation emerged between plasma and whey IL-1beta concentrations. The average CD4(+)/CD8(+) ratio in blood was lower in HC than in LC ewes. Time from isolation affected the CD4(+)/CD8(+) ratio: at 120 min, the CD4(+)/CD8(+) ratio increased compared with that at 10 min after isolation and then decreased until 300 min after isolation. On average, ewes with low cortisol concentrations showed higher milk production and lower SCC than ewes with high cortisol concentrations. Results suggest that plasma cortisol concentration is connected to the behavioral response and immune competence of dairy ewes and cytokine concentrations. Both whey IL-1beta and IL-6 can be considered reliable indicators of the magnitude of hypothalamic-pituitary-adrenal axis activation. The stress-induced changes in CD4(+)/CD8(+) ratio are critical for controlling disease incidence and planning appropriate vaccination programs. High reactivity of the hypothalamic-pituitary-adrenal axis is also associated with a reduction in milk production and an increased predisposition to develop intramammary inflammatory processes.

Influence of space allowance and housing conditions on the welfare, immune response and production performance of dairy ewes.

The experiment used 45 Comisana ewes, divided into 3 groups of 15. The aim was to determine the effects of two different stocking densities and two different housing conditions on welfare, and on production performance of dairy ewes. The stocking densities tested were: high stocking density (1 x 5 m2/ewe, HD group) and low stocking density (3 m2/ewe, LD group); the two housing conditions tested were: ewes housed indoors (LD group, 3 m2/ewe) and ewes allowed to use an outdoor area (LDP group, 3 m2/ewe divided into 1 x 5 m2/ewe indoors and 1 x 5 m2/ewe outdoors). At the beginning of the experiment, and then every 2 months, the cell-mediated immune status of sheep was evaluated. One month after the beginning of the experiment, and 20 d later, the ewes were injected with chicken egg albumin (OVA) to assess their humoural immune responses. Starting from the beginning of the experiment and then monthly, behavioural activities of ewes were monitored using 15-min scans. After lamb weaning, milk yield from individual ewes was measured and milk composition analysed weekly. Housing conditions (low density reared ewes indoors v. low density reared ewes with free access to an outdoor area) affected cell-mediated response, which was higher in LDP than in LD ewes. Concentrations of anti-OVA IgG were mainly influenced by space allowance, with higher antibody titres in LD than in HD ewes throughout the experiment. Both housing conditions and space allowance affected sheep behavioural activities: a greater proportion of LDP ewes displayed standing and drinking behaviours than LD ewes, and a greater proportion of LD ewes was observed walking than HD ewes. Ewes allowed access to the outdoor area had a higher protein content and lower somatic cell count in their milk, whereas reduced space allowance led to a reduction in milk yield and an increase in somatic cell count of milk. Results indicate that both increased space allowance and availability of outdoor area can improve the welfare and production performance of the lactating ewe.

Influence of ventilation regimen on micro-environment and on ewe welfare and milk yield in summer

Abstract The effects of ventilation regimen on air quality, and on the welfare and production performance of thirty-six Comisana ewes were assessed in a 6-week trial conducted during the summer of 2002. Animals were divided into three groups of 12, and subjected to the following treatments: low ventilation regimen providing a mean ventilation rate (VR) of 35 m3/h per ewe, split in 30 min ventilation cycles at an air speed of 2 m/s (LOV-30); moderate ventilation regimen (VR = 70 m3/h per ewe) split in 30 min ventilation cycles at an air speed of 4 m/s (MOV-30); moderate ventilation regimen (VR = 70 m3/h per ewe) split in 60 min ventilation cycles at an air speed of 2 m/s (MOV-60). Air concentrations of microorganisms, dust, and gaseous pollutants were measured twice weekly. Respiration rate (RR) and rectal temperature (RT) were monitored throughout the trial at 0830 and at 1400. Behavioral traits of ewes were recorded twice per week from 0900 to 1200 and from 1500 to 1800. Cell-mediated immune response to phytohemagglutinin (PHA) and humoral immune response to chicken egg albumin were determined. At d 37 ewes were injected with porcine ACTH, and subjected to blood sampling for evaluation of cortisol concentrations immediately before and 1, 2 and 4 h after ACTH injection. Milk yield was recorded daily. Individual milk samples were analyzed for composition, renneting parameters, somatic cell count (SCC), and bacteriological characteristics. Averages of maximum THI were about 3 points higher in the LOV-30 and the MOV-30 than in the MOV-60 room, whereas no differences emerged in the air concentrations of dust, gaseous pollutants and microorganisms. Significant interactions of treatment x time (P < 0.05) were found for respiration rate, and for the time the ewes spent lying, idling and eating in the afternoon during weeks 2 and 3 of the study period. Significant effects of ventilation regimen x time (P < 0.05) were also observed for milk yield and milk renneting parameters, the LOV-30 ewes giving smaller volumes of milk with a deteriorated coagulating behavior than those of the MOV-60 group during the second half of the trial. No significant differences emerged in ewe immune and endocrine responses. Results show that ventilation regimen had a moderate impact on ewe behavior, physiology and production performance. This experiment suggests that the length of ventilation cycles and air speed, together with ventilation rate, are critical for efficient ventilation regimens.

Hypothalamic-pituitary-adrenal axis activation and immune regulation in heat-stressed sheep after supplementation with polyunsaturated fatty acids

The aim of this study was to assess the effects of supplementation with polyunsaturated fatty acids from different sources on immune regulation and hypothalamic-pituitary-adrenal (HPA) axis activation in heat-stressed sheep. The experiment was carried out during the summer 2012. Thirty-two Comisana ewes were divided into 4 groups (8 sheep/group): (1) supplemented with whole flaxseed (FS); (2) supplemented with Ascophyllum nodosum (AG); (3) supplemented with a combination of flaxseed and A. nodosum (FS+AG); and (4) control (C; no supplementation). On d 22 of the experiment, cortisol concentrations in sheep blood were measured after an injection of ACTH. Cellular immune response was evaluated by intradermic injection of phytohemagglutinin (PHA) at 0, 15, and 30 d of the trial. Humoral response to ovalbumin (OVA) was measured at 0, 15, and 30 d. At 0, 15, and 30 d of the experiment, blood samples were collected from each ewe to determine production of T-helper (Th)1 cytokines (IL-12 and IFN-γ), and Th2 cytokines (IL-10, IL-4, IL-13), and concentrations of heat shock proteins (HSP) 70 and 90. Ewes supplemented with flaxseed alone had greater cortisol concentrations and a longer-lasting cell-mediated immune response compared with ewes in the control and other groups. Anti-OVA IgG concentrations increased in all groups throughout the trial, even though ewes in the FS+AG group had the lowest anti-OVA IgG concentrations at 15 d. The level of IL-10 increased in all groups throughout the experiment; the FS+AG group had the lowest IL-13 concentration at 15 and 30 d. The concentration of HSP 70 increased in AG ewes at the end of the experiment and decreased in FS ewes, whereas that of HSP 90 increased in FS ewes compared with FS+AG ewes. Flaxseed supplementation was found to influence in vivo HPA activation in heat-stressed sheep, resulting in increased cortisol concentrations, probably to meet increased energy demand for thermoregulation. Flaxseed supplementation also supported Th1 response via a complex cross-talk between IL-10, IL-12, and IFN-γ production.

Effects of dietary protein level on ewe milk yield and nitrogen utilization, and on air quality under different ventilation rates

The experiment, which lasted 53 d, was conducted during the winter (February and March) of 2004 and used 48 Comisana ewes in mid lactation. A 2 x 2 factorial design was used, with ewes receiving two levels of dietary crude protein (CP) (moderate, 16% CP v. low, 13% CP) in the dry matter (DM) and being exposed to two ventilation rates (moderate, 47 m3/h v. low, 23.5 m3/h per ewe) for each dietary treatment. Air concentrations of NH3 and of microorganisms were measured twice weekly. Milk yield was recorded daily. Individual milk samples were analysed weekly for composition and fortnightly for bacteriological characteristics. After the last milk sampling (day 49 of the study period), four animals from each group were placed in a metabolism box and their individual faeces and urine were collected for three consecutive days. Amounts of urine and faeces excreted, and urinary and faecal N outputs were measured. The 16% CP diet resulted in a lower milk casein content and a higher milk urea concentration than the 13% CP diet, as well as in a reduced gross efficiency of utilization of dietary N, a greater amount of N excreted and a higher total coliform concentration in milk. The moderate ventilation rate resulted in higher yields of milk, irrespective of CP content. Significant interactions of CP level x ventilation rate were found for the amounts of urine, of total water and of faecal N, and for mesophilic concentration in milk, the highest values being displayed by the ewes fed the 16% CP diet and exposed to the low ventilation rate. The moderate dietary CP level and low ventilation rate had a deleterious effect on air concentrations of microorganisms and ammonia. Results suggested that a reduction of dietary CP level from 16 to 13% of DM had no detrimental effect on ewe milk yield in mid lactation and could even improve some of its nutritional and hygienic characteristics. Our findings also indicate that the choice of a proper ventilation rate is critical for high efficiency of production in the lactating ewe, especially in intensively managed flocks receiving diets high in CP.

Effect of Manure vs. Fertilizer Inputs on Productivity of Forage Crop Models

Manure produced by livestock activity is a dangerous product capable of causing serious environmental pollution. Agronomic management practices on the use of manure may transform the target from a waste to a resource product. Experiments performed on comparison of manure with standard chemical fertilizers (CF) were studied under a double cropping per year regime (alfalfa, model I; Italian ryegrass-corn, model II; barley-seed sorghum, model III; and horse-bean-silage sorghum, model IV). The total amount of manure applied in the annual forage crops of the model II, III and IV was 158, 140 and 80 m3 ha−1, respectively. The manure applied to soil by broadcast and injection procedure provides an amount of nitrogen equal to that supplied by CF. The effect of manure applications on animal feeding production and biochemical soil characteristics was related to the models. The weather condition and manures and CF showed small interaction among treatments. The number of MFU ha−1 of biomass crop gross product produced in autumn and spring sowing models under manure applications was 11,769, 20,525, 11,342, 21,397 in models I through IV, respectively. The reduction of MFU ha−1 under CF ranges from 10.7% to 13.2% those of the manure models. The effect of manure on organic carbon and total nitrogen of topsoil, compared to model I, stressed the parameters as CF whose amount was higher in models II and III than model IV. In term of percentage the organic carbon and total nitrogen of model I and treatment with manure was reduced by about 18.5 and 21.9% in model II and model III and 8.8 and 6.3% in model IV, respectively. Manure management may substitute CF without reducing gross production and sustainability of cropping systems, thus allowing the opportunity to recycle the waste product for animal forage feeding.

Alterations in sheep peripheral blood mononuclear cell proliferation and cytokine release by polyunsaturated fatty acid supplementation in the diet under high ambient temperature

The aim of this study was to investigate the effects of polyunsaturated fatty acid (PUFA) supplementation from different sources in the diet of dairy sheep under high ambient temperatures on ex vivo lymphocyte proliferation and inflammatory responses. The experiment was carried out during summer: 32 Comisana ewes were divided into 4 groups of 8. The FS group was supplemented with whole flaxseed, the AG group was supplemented with Ascophyllum nodosum, the FS+AG group was supplemented with a combination of flaxseed and A. nodosum. The fourth group (CON group) was a control and received a diet containing no supplement. The average maximum temperature was around 33°C during wk 2 and 3, whereas the mean temperature never decreased below 26°C. Following 15 d of treatment with respective diets, peripheral blood mononuclear cells (PBMC) from sheep who received a diet supplemented with A. nodosum had impaired cell proliferation responses and IL-6 production after mitogen stimulation compared with PBMC from FS+AG sheep. In addition, PBMC from AG sheep displayed impaired cell proliferation compared with cells from the CON group. The FS+AG cells produced lower levels of IL-10 than CON cells, and higher IL-6 than AG and CON cells. Results demonstrated that the supplementation with PUFA from different sources in a sheeps diet can influence their immunological responses under high ambient temperatures depending on the composition of fatty acid supplementation. In particular, synergistic effects of different PUFA from flaxseed and A. nodosum, simultaneously administrated in the sheep diet, were observed on activation of inflammation response.