In reproducing ewes, a periparturient breakdown of immunity is often observed to result in increased fecal egg excretion, making them the main source of infection for their immunologically naive lambs. In this study, we expanded a simulation model previously developed for growing lambs to explore the impact of the genotype (performance and resistance traits) and host nutrition on the performance and parasitism of both growing lambs and reproducing ewes naturally infected with Teladorsagia circumcincta. Our model accounted for nutrient-demanding phases, such as gestation and lactation, and included a supplementary module to manage the age structure of the ewe flock. The model was validated by comparison with published data. Because model parameters were unknown or poorly estimated, detailed sensitivity analysis of the model was performed for the sheep mortality and the level of infection, following a preliminary screening step. The parameters with the greatest effect on parasite-related outputs were those driving animal growth and milk yield. Our model enables different parasite-control strategies (host nutrition, breeding for resistance and anthelmintic treatments) to be assessed on the long term in a sheep flock. To optimize in silico exploration, the parameters highlighted by the sensitivity analysis should be refined with real data.

Piglet survival is a major problem, especially during the first 3 days after birth. Piglets are born deficient of energy, but at the same time they have a very high energy requirement because of high physical activity, high need for thermoregulation (because of their lean body with low insulation) and high heat production in muscle tissues. To be able to survive, newborn piglets may rely upon three different sources of energy, namely, glycogen, colostrum and transient milk, which orchestrate to cover their energy requirements. Piglets are born with limited amounts of energy in glycogen depots in the liver and muscle tissues and these depots are sufficient for normal activity for ∼16 h. Intake and oxidation of fat and lactose from colostrum must supply sufficient amount of energy to cover at least another 18 h until transient milk becomes available in the sow udder ∼34 h after the first piglet is born. Selection for large litters during the last two decades has challenged piglets even further during the critical neonatal phase because the selection programs indirectly decreased birth weight of piglets and because increased litter size has increased the competition between littermates. Different attempts have been made to increase the short-term survival of piglets, that is, survival until day 3 of lactation, by focusing on improving transfer of vital maternal energy to the offspring, either in utero or via mammary secretions. Thus, the present review addresses how sow nutrition in late gestation may favor survival of newborn piglets by increasing glycogen depots, improving colostrum yield or colostrum composition, or by increasing production of transient milk.

The aim of this study was to evaluate whether the peripheral cytokine expression could be affected by differences in fat thickness in healthy mares during the periparturient period (last weeks of pregnancy and first weeks of lactation). At the beginning of the 11th month of gestation, 18 mares with normal body condition score (BCS; 5) were divided into two groups with low (L; ⩽12 mm; n = 12) and high (H; >12 mm; n = 6) fat thickness. Blood samples were collected every 10 days from the 11th month of gestation to 20 days post partum. Peripheral blood mononuclear cells were separated and tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1α (IL-1α), -1β (ILβ), -2 (IL-2) and -6 (IL-6) gene expressions were performed by using reverse transcriptase PCR. TNF-α and IFN-γ expressions were affected by fatness group, as the sampling period influenced the expression of all cytokines with the exception of IFN-γ. The interaction between fatness group and sampling period tended to be significant (P < 0.10) only for IL-1β, TNF-α and IL-2. In H group, compared with L group, IL-1β and IL-2 significantly (P < 0.05) increased at parturition. TNF-α peripheral expression increased from parturition to reach the peak at +10 days (P < 0.05) only in H group. In conclusion, in normal BCS periparturient mares, small body fat thickness variations influence the peripheral cytokine expression, showing a possible role for cytokines in parturition and lactation, events strongly linked to adipose tissue availability.

This paper reports the results of a study that aimed to assess whether liver functionality defined by liver activity index (LAI) is associated with inflammatory and immune parameters in blood and milk. LAI is an index including the average blood levels of albumin, lipoproteins and retinol-binding protein measured three times in the first month of lactation (at 5, 15 and 30 days in milk). The aim was to assess the relationship of this index with blood and udder immune and inflammatory status as a means of identifying as early as possible cows at risk of disease. The research was carried out using 10 multiparous Italian-Friesian dairy cows of average genetic merit. Cows were retrospectively ranked in three groups according the LAI level. Blood samplings were performed at different intervals before and after calving; quarter milk samples were taken only after calving with the same schedule as blood samples. Leucocytes, oxidative burst, blood lysozyme and N-acetyl-β-d-glucosaminidase (NAGase) curves showed large overlapping among the three LAI group curves during the follow-up period. Four blood (complement, sialic acid, haptoglobin and reactive oxygen metabolites) and three milk (somatic cell count, lysozyme and NAGase) parameters showed larger and more consistent differences among LAI groups. Complement showed higher values and sialic acid showed lower values in high LAI group when compared with the other two LAI groups. Two other markers of inflammatory status (haptoglobin and reactive oxygen metabolites) showed the lowest values in high LAI cows. A consistent and significant reduction of milk NAGase and milk lysozyme in high LAI group was observed. The results suggest that cows with the highest liver functionality index have also the highest levels of some immune markers and the lowest levels for inflammatory markers at blood (already before calving) and mammary levels. Finally, cows with low LAI index, being more susceptible to metabolic and infectious diseases, should be carefully monitored to identify as early as possible the development of a disease.

The aim of this study was to compare the effects of supplementing dairy cows with 1000 IU/day of all-rac-α-tocopheryl acetate (SynAc), RRR-α-tocopheryl acetate (NatAc), or RRR-α-tocopherol (NatAlc), from approximately 3 weeks before estimated calving until 2 weeks after calving, on the concentration of α-tocopherol and its stereoisomers (RRR-, RSS-, RRS-, RSR- and the four 2S-forms of α-tocopherol) in blood and milk. An unsupplemented group was included as control. Blood samples were collected at 3, 2 and 1 weeks before estimated calving, at calving, and 3, 7 and 14 days after calving, while milk samples were taken twice within 24 h after calving and at 7 and 14 days in milk. Overall, time and treatment had significant effects on plasma α-tocopherol with higher concentrations in NatAc than in the other groups. In addition, SynAc had higher concentrations than Control, and NatAlc tended to be higher than Control. The lowest plasma concentrations were observed at calving and 3 days after calving. Independent of treatment, the concentration was higher in colostrum than in milk day 7 and 14 after calving. Analyses of the stereoisomer distribution in plasma and milk showed that, irrespective of dietary treatment, RRR-α-tocopherol was the most predominant form, constituting more than 86%, whereas the remaining part of α-tocopherol was made up by the three synthetic 2R isomers, while the 2S isomers only contributed less than 1% of the total α-tocopherol. In control cows and cows supplemented with natural vitamin E, the proportion of RRR-α-tocopherol in plasma and milk constituted more than 98% of the total α-tocopherol. In conclusion, the results indicate that daily oral supplementation of dairy cows with RRR-α-tocopheryl acetate gives the highest blood concentrations of α-tocopherol in the periparturient period. Analyses of the distribution of the individual stereoisomers of α-tocopherol further indicate that the bioavailability of RRR-α-tocopherol relative to synthetic stereoisomers in cattle is considerably higher than officially accepted until now.