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Enhancing longevity by reducing involuntary culling and consequently increasing productive life and lifetime production of dairy cows is not only a strategy to improve a farm’s profit, but is also related to improved animal welfare. High rates of involuntary culling in dairy cows are currently attributed to fertility problems, mastitis and locomotive disorders. Disease incidence is high in particular in the early-lactation period. The high disease incidence in early lactation has been attributed to metabolic stress related to the high metabolic priority for lactation and the inability of the cow to adapt effectively to the new lactation. Several biological mechanisms interact in the peripartum period of dairy cows and can result in this inability to adapt effectively to lactation. Biological mechanisms reviewed are metabolic adaptation, oxidative stress, immune function and inflammation, and feed intake capacity. Although relationships between these mechanisms become increasingly clear, these relationships are complex and not yet completely understood. Appro- priate management of dairy cows in the peripartum period can facilitate cows to adapt to a new lactation. Nutritional and management strategies to ease adaptation are divided into strategies to restrict energy intake in the dry period, to improve energy intake in early lactation, alter repar- titioning of energy between milk and body tissue, and strategies to support fat or carbohydrate metabolism. The success of various strategies, however, is often hampered by the complexity of interactions and high between-cow variation. We advocate for a multidisciplinary approach to understand and manage adaptation to a new lactation aiming at an improvement of cow welfare and longevity

Enhancing longevity by reducing involuntary culling and consequently increasing productive life and lifetime production of dairy cows is not only a strategy to improve a farm's profit, but is also related to improved animal welfare. High rates of involuntary culling in dairy cows are currently attributed to fertility problems, mastitis and locomotive disorders. Disease incidence is high in particular in the early-lactation period. The high disease incidence in early lactation has been attributed to metabolic stress related to the high metabolic priority for lactation and the inability of the cow to adapt effectively to the new lactation. Several biological mechanisms interact in the peripartum period of dairy cows and can result in this inability to adapt effectively to lactation. Biological mechanisms reviewed are metabolic adaptation, oxidative stress, immune function and inflammation, and feed intake capacity. Although relationships between these mechanisms become increasingly clear, these relationships are complex and not yet completely understood. Appropriate management of dairy cows in the peripartum period can facilitate cows to adapt to a new lactation. Nutritional and management strategies to ease adaptation are divided into strategies to restrict energy intake in the dry period, to improve energy intake in early lactation, alter repartitioning of energy between milk and body tissue, and strategies to support fat or carbohydrate metabolism. The success of various strategies, however, is often hampered by the complexity of interactions and high between-cow variation. We advocate for a multidisciplinary approach to understand and manage adaptation to a new lactation aiming at an improvement of cow welfare and longevity.

The length of the dry period in commercial dairy production is under close scrutiny. While the main concern is the composition and volume of milk produced, the evaluation of colostrum quality under these new paradigms has suggested a decline in IgG concentrations, while some reports indicate no change. Colostrum quality has been defined as an adequate concentration (>50 mg/ml) of immunoglobulin in the secretions to provide the newborn with maximal disease resistance. We investigated the appearance of IgG in mammary pre- and post partum secretions in cows without a dry period (continuously milked, Dry0) and compared the secretions with cows that experienced a dry period of 60 d (Dry60). Blood was collected during the experimental period and plasma analysed for progesterone (P4) and prolactin (Prl). Approximately −6 d relative to parturition, the Dry0 animals exhibited increased concentration of IgG in their secretions to an average of ∼35 mg/ml that remained rather constant through subsequent pregnancy and following parturition. Dry0 cows were producing an average IgG concentration in parturition colostrum of 44·2±17·6 mg/ml that was not different than that of controls (66·86±16·8 mg/ml). However, Dry0 cows exhibited high variation, different peak times (day) of IgG concentration including times that occurred both pre and post parturition. IgG mass of the Dry0 cows remained rather constant pre- and post partum and did not show the same declining mass following parturition that was shown for the Dry60 cows. The change in plasma P4 and Prl were shown to have no timing effect on colostrum IgG concentration.

Shortening the dry period could have positive health, fertility and milk production benefits, but more research is needed to ensure that science and husbandry keep pace with the modern dairy cow. We spoke to a leading dairy research scientist and a vet to find out more.

Op welke manier droogstaande koeien gevoerd moeten worden, is al vaak benoemd. Maar waarom we dingen doen zoals ze geadviseerd worden, is wat minder bekend. In de aanloop naar een nieuwe lactatie spelen twee stromen een belangrijke rol in de stofwisseling. Bewustwording van wat de effecten zijn van een verstoorde energie- en calciumhuishouding, draagt bij aan een goede opstart van de melkkoe.

De droogstand van melkkoeien heeft een positief effect op de melkproductie in de volgende lactatie. Het opnieuw opstarten van de lactatie is echter gerelateerd aan gezondheids- en vruchtbaarheidsproblemen. Uit onderzoek blijkt dat verkorten van de droogstand de energiebalans verbetert.

In de huidige melkveehouderij is een droogstandsperiode voor afkalven van 6 tot 8 weken gangbaar. Recente resultaten uit de internationale literatuur laten echter zien dat het verkorten of zelfs weglaten van de droogstand een interessante strategie kan zijn om gezondheidsproblemen bij melkvee in de vroege lactatie te verminderen.

Objectives: To compare the preverbal communication skills of two groups of young implanted children: those with unilateral implantation and those with bilateral implantation. Material and methods: The study assessed 69 children: 42 unilaterally and 27 bilaterally implanted with age at implantation less than 3 years. The preverbal skills of these children were measured before and 1 year after implantation, using Tait Video Analysis that has been found able to predict later speech outcomes in young implanted children. Results: Before implantation there was no significant difference between the unilateral group and the bilateral group. There was still no difference at 12 months following implantation where vocal autonomy is concerned, but a strongly significant difference between the groups for vocal turn-taking and non-looking vocal turns, the bilateral group outperforming the unilateral group. Regarding gestural turn-taking and gestural autonomy, there was a strongly significant difference between the two groups at the 12 month interval, and also a difference before implantation for gestural autonomy, the unilateral group having the higher scores. Multiple regression of non-looking vocal turns revealed that 1 year following implantation, bilateral implantation contributed to 51% of the variance (p < 0.0001), after controlling for the influence of age at implantation and length of deafness which did not reach statistical significance. Conclusions: Profoundly deaf bilaterally implanted children are significantly more likely to use vocalisation to communicate, and to use audition when interacting vocally with an adult, compared with unilaterally implanted children. These results are independent of age at implantation and length of deafness. © 2009.

Waarom zetten we koeien eigenlijk droog? WUR-onderzoekster Ariëtte van Knegsel ging op zoek naar een antwoord, maar vond het niet. "Een droogstand van 6 tot 8 weken geeft een piek in de productie, maar blijkt verder vooral een kwestie van traditie". Daarom leidt ze sinds juni het onderzoek 'Why Dry?', waarbij koeien op de Waiboerhoeve 60, 30 of 0 dagen droog staan en twee lactaties worden gevolgd.

In this literature review, the physiological basis for possible differences in energy and protein requirements of organic versus conventional poultry is investigated. Energy need for maintenance of organic housed poultry seems to be increased, whereas protein requirements might not differ between the two systems. This might result in an increased energy to protein ration in organic diets. In dit literatuuronderzoek is nagegaan of er een fysiologische basis is voor de mogelijke verschillen in energie- en eiwitbehoefte van biologische gehouden pluimvee in vergelijking met conventioneel gehouden pluimvee. Biologisch pluimvee lijkt wel een hogere onderhoudsbehoefte voor energie te hebben, maar niet voor eiwit. Dit pleit voor een hogere energie-eiwitverhouding in biologische pluimvee voeders

De gedachte is dat de energie- en eiwitbehoeften van biologisch gehouden pluimvee verschilt van die van gangbaar gehouden kippen. Om meer zicht te krijgen op dit verschil in behoeften, is een literatuuronderzoek uitgevoerd

For several decades, researchers worldwide report a decrease in fertility in high-yielding dairy cows, most probably based on conflicting metabolic and reproductive needs. The dairy herd manager's success at improving milk production has been accompanied by a negative trend for the most visible reproductive parameters such as calving intervals, number of days open and number of inseminations needed per pregnancy. In parallel, many research groups studied the metabolic and endocrine factors that influence follicular growth and the developmental competence of oocytes and embryos. In the past, herd managers and reproductive biologists each tried to tackle the same problems with limited consultation. More recently, the situation has improved significantly and theriogenologists, nutritionists and veterinarians now conduct research in multidisciplinary teams. This review paper starts in a general way by discussing nutrient prioritization towards the udder to guarantee milk production and by describing interactions between the somatotropic and gonadotropic axis. It then focuses on the consequences of the negative energy balance on follicular growth and environment, oocyte and embryo quality, not only by summarizing the currently accepted hypotheses but also based on clear scientific evidence at the follicular level. All this, with one question in mind: is there a mismatch between metabolism and fertility and what can the dairy manager learn from research to tackle the problem of reduced fertility?

The objective of this study was to determine whether concentrations of specific fatty acids in milk fat are a candidate for the early detection of subclinical ketosis. The case study included multiparous cows fed a lipogenic diet or a mixed glucogenic:lipogenic diet during the first 9 wk of lactation. Milk fatty acid profiles of cows classified as healthy (n = 8) or as subclinically ketotic (n = 8) based on a blood plasma β-hydroxybutyrate threshold concentration of 1.2 mmol/L were compared. Subclinically ketotic cows showed an elevated proportion of C18:1 cis -9 in milk fat during the whole registration period.

The objectives of this study were to determine the presence of natural antibodies (NAb) in plasma and milk of individual dairy cows and to study the relation between NAb concentrations and energy balance (EB) and dietary energy source. Cows (n = 76) were fed a mainly glucogenic, lipogenic, or a mixture of both diets (50: 50 dry matter basis) from wk 3 before the expected calving date until wk 9 postpartum. Diets were isocaloric (net energy basis) and equal in intestinal digestible protein. Blood and milk were sampled weekly. Liver biopsies were taken in wk -2, 2, 4, and 6 relative to calving. Data are expressed as LSM +/- SEM. The NAb titers are expressed as the (2)log values of the highest dilution giving a positive reaction. The NAb concentration in plasma binding either keyhole limpet hemocyanin (KLH) or Escherichia coli lipopolysaccharide (LPS) increased with parity. The NAb concentration binding KLH was greater for cows fed the glucogenic diet (9.63 +/- 0.08) compared with the lipogenic diet (9.26 +/- 0.08). In milk, cows fed the glucogenic diet had smaller NAb concentrations binding KLH (3.98 +/- 0.18) and LPS (2.88 +/- 0.17) compared with cows fed the mixed diet (KLH: 4.93 +/- 0.18; LPS: 3.70 +/- 0.17). The NAb concentration in plasma had a positive relation with energy balance variables: EB, dry matter intake, milk yield, and plasma cholesterol, whereas NAb concentration in milk had a negative relation with energy balance variables: EB, dry matter intake, and plasma cholesterol. Additionally, NAb concentrations in milk had a positive relation with plasma nonesterified fatty acid concentration and milk fat and protein percentage. There was a tendency for a positive relation of NAb concentration binding LPS in plasma and somatic cell count in milk. No significant relations were detected between NAb concentrations in milk or plasma and plasma beta-hydroxybutyrate concentration and liver triacyl glyceride content. In conclusion, NAb are present in both milk and plasma of dairy cows peripartum and NAb concentrations increase with parity. Furthermore, our data indicate that a negative energy balance in dairy cows in early lactation can be associated with compromised innate immune function as indicated by decreased NAb concentration in plasma.

Negative energy balance-related metabolic disorders suggest that the balance between available lipogenic and glucogenic nutrients is important. The objectives of this study were to compare the effects of a glucogenic or a lipogenic diet on liver triacylglycerides (TAG), metabolites, and metabolic hormones in dairy cows in early lactation and to relate metabolite concentrations to the determined energy retention in body mass (ER). Sixteen dairy cows were fed either a lipogenic or glucogenic diet from wk 3 prepartum to wk 9 postpartum (pp) and were housed in climate respiration chambers from wk 2 to 9 pp. Diets were isocaloric (net energy basis). Postpartum, cows fed a lipogenic diet tended to have higher nonesterified fatty acid concentration (NEFA; 0.46 +/- 0.04 vs. 0.37 +/- 0.04 mmol/L) and lower insulin concentration (4.0 +/- 0.5 vs. 5.5 +/- 0.6 microIU/mL). No difference was found in plasma glucose, beta-hydroxybutyrate, insulin-like growth factor-I, and thyroid hormones. Liver TAG was equal between both diets in wk -2 and 2 pp. In wk 4 pp cows fed the glucogenic diet had numerically lower TAG levels, although there was no significant dietary effect. Negative relationships were detected between ER and milk fat and between ER and NEFA. A positive relationship was detected between ER and insulin concentration. Overall, results suggest that insulin plays a regulating role in altering energy partitioning between milk and body tissue. Feeding lactating dairy cows a glucogenic diet decreased mobilization of body fat compared with a lipogenic diet. The relative abundance of lipogenic nutrients, when feeding a more lipogenic diet, is related to more secretion of lipogenic nutrients in milk, lower plasma insulin, and higher plasma NEFA concentration.

Elke koe kampt aan het begin van de lactatie met een negatieve energiebalans. Aandacht voor de juiste vorm van energie in het rantsoen is geen overbodige luxe, blijkt uit onderzoek. Een glucogeen rantsoen heeft de voorkeur boven een lipogeen rantsoen

Keywords: dairy cows; dietary energy source; glucogenic nutrients; lipogenic nutrients; negative energy balance; metabolic disorders; reproduction, immune system Dairy cows experience a negative energy balance (NEB) in early lactation which results from high energy requirements for milk production accompanied by a limited energy intake. Nutrition has been indicated as an important factor in the incidence and severity of NEB and NEB–related metabolic and reproductive disorders, like ketosis and delayed resumption of ovarian activity. A metabolic effect of a NEB in dairy cows is suggested to be an unbalanced availability from glucogenic and lipogenic nutrients. The objective of this thesis was to study the effect of lipogenic and glucogenic diets on the energy balance (EB) and risk of metabolic and reproductive disorders in dairy cows in early lactation. The first study, a literature survey, illustrated that feeding extra glucogenic nutrients relative to lipogenic nutrients, decreased milk fat and seemed to decrease plasma non-esterified fatty acid (NEFA) and β-hydroxybutyrate (BHBA) concentrations. Since studies were scarce and mostly included a confounding effect of dietary energy source with energy intake, it was difficult to draw conclusions on the energy source effects on EB and fertility. Therefore, in the second study, 16 dairy cows were either fed a glucogenic or a lipogenic diet. Diets were isocaloric and equal in intestional digestible protein. Energy balance was determined in climate-respiration chambers from week 2 until week 9 of lactation. The glucogenic diet decreased milk fat yield and milk energy and tended to decrease body fat mobilisation compared with the lipogenic diet. The objective of the third study was to study the effect of dietary energy source on EB, metabolites and some reproduction variables. Dairy cows (n=111) were fed glucogenic, lipogenic or mixed diet from week -3 until week 9 relative to calving. Multiparous cows fed the glucogenic diet had lower milk fat yield, higher calculated EB, and lower plasma NEFA, BHBA and liver tri-acyl glyceride concentration and tended to have less days postpartum till first ovulation. Additionally, in the third study, the presence of natural antibodies (NAb) in plasma and milk of individual dairy cows was determined. Relations were detected between NAb and EB and plasma metabolites, suggesting that alterations in immune competence peripartum are reflected in the humoral part of the innate immune system. In conclusion, increasing the glucogenic nutrient availability improved the EB and had potential to reduce the risk of metabolic disorders and to improve reproductive performance in dairy cows.

Wageningen UR, Schothorst Feed Research en de faculteit Diergeneeskunde hebben een gezamenlijke literatuurstudie uitgevoerd om de mogelijkheden van een kortere droogstand te verkennen. De gevonden voordelen worden genoemd, maar een uitspraak over de optimale lengte van de droogstand is nog niet te doen

GH receptor (GHR) mRNA is expressed in bovinein vitroproduced embryos up to the blastocyst stage and GH improves the quality of bovine embryos by increasing blastocyst cell numbers and reducing the incidence of apoptosis as evaluated by DNA strand-break labelling. Porcinein vitroproduced blastocysts have lower cell numbers thanin vivoblastocysts and exhibit higher incidences of apoptosis. Therefore we investigated the effects of 100 ng GH/ml NCSU23 medium duringin vitroculture of presumptivein vitrofertilized sow zygotes on embryo development and blastocyst quality (defined by diameter, cell number, apoptosis and survival after non-surgical transfer).In vivoproduced blastocysts were analysed concurrently as a reference value. GHR was expressed in embryos from the 2-cell to blastocyst stages. GH had no effect on blastocyst development or cell numbers, but increased the mean blastocyst diameter. The incidence of apoptosis, detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL), was decreased by GH, but when non-TUNEL-labelled apoptotic fragmented nuclei were included, no difference was seen. GH appeared to slow down the progression of apoptosis though.In vivoproduced blastocysts presented no apoptotic nuclei, and contained higher cell numbers and larger diameters. Pregnancy rates on day 11 were similar for all groups, but survival was poorer forin vitrothanin vivoproduced blastocysts. In this study GH appeared to be beneficial only from the blastocyst stage, but the presence of GHR from early cleavage stages nevertheless indicates a role for GH throughout porcine embryo development and deserves further investigation.