The association between herd- and cow-level factors and somatic cell count of Irish dairy cows

peer-reviewedSomatic cell count (SCC) is an indicator of both udder health and milk quality and is measured at an animal level through national milk recording schemes. The objective of this study was to assess the animal and herd factors contributing to elevated SCC (i.e. poorer milk quality). Test day records (n = 2,658,928) from 519,456 cow lactations obtained between 2007 and 2011 were included in the analyses. Herd factors tested included the geographical region of the herd and production system operated (spring calving or mixed calving system). Animal factors tested included breed, parity and age nested within parity. Four definitions of normalised SCC (i.e. SCS) were considered: 1) average test-day SCS within a 24 hour period (TD_SCS), 2) maximum SCS (peak_SCS), 3) minimum SCS (min_SCS), and 4) average SCS (avg_SCS) recorded across cow lactation; in addition, the proportion of test day records with an SCC count >200,000 (prop_200) or >250,000 (prop_250) within cow lactation were included. Following adjustment for fixed effects, average TD_SCS was 179,308 cells per mL while avg_SCS, and average min_SCS and peak_SCS were 119,481, 50,992 and 298,813 cells per mL, respectively. All animal and herd factors had a significant effect on SCC. Older animals, animals which were younger at calving than contemporaries and Holstein animals had higher SCC than younger alternative breed animals who calved at the median age. In addition, mixed calving production systems and herds in Connaught had higher SCC than spring calving herds in the other regions of Ireland.The authors gratefully acknowledge funding for this work from the Department of Agriculture, Fisheries and Food under the Joint FIRM / RSF Initiative (Project Number: 10/RD/AAQUALITYMILK/ TMFRC713)

Animal Transport: Developing optimum animal handling procedures and effective transport strategies in the food production chain to improve animal welfare and food quality

End of project reportA series of studies were performed to investigate the effect of transport on liveweight, physiological and haematological responses of cattle. The first study was carried out over a 6 week period in the Spring of 2004. Eighty-four continental x bulls (mean weight (s.d.) 367 (35) kg), naïve to transport, were randomly assigned to one of six journey (J) times of 0, 6, 9, 12, 18 and 24h transport at a stocking density of 1.02m2/bull. Blood samples were collected by jugular venipuncture before, immediately after and at 1, 2, 4, 6, 8, 12 and 24h and bulls were weighed before, immediately after, and at 4, 12 and 24h. Bulls travelling for 6h (280 km), 9h (435 km), 12h (582 km), 18h (902 km) and 24h (1192 km) lost 4.7, 4.5, 5.7 (P=0.05), 6.6 (P=0.05) and 7.5 (P=0.05) percentage liveweight compared with baseline. During the 24h recovery period liveweight was regained to pre-transport levels. Lymphocyte percentages were lower (P=0.001) and neutrophil percentages were higher (P=0.05) in all animals. Blood protein and creatine kinase, glucose and NEFA concentrations were higher (P=0.05) in the bulls following transport and returned to baseline within 24h. In conclusion, liveweight and some physiological and haematological responses of bulls returned to pre-transport levels within 24h having had access to feed and water. Transport of bulls from 6 – 24hours did not impact negatively on animal welfare

The effect of abrupt weaning of suckler calves on the plasma concentrations of cortisol, catecholamines, leukocyte, acute-phase proteins and in vitro interferon-gamma production

End of project reportThe objective of this study was to examine the effect of abrupt weaning (inclusive of social group disruption and maternal separation) on the physiological mediators of stress and measures of immune function. Thirty-eight male and 38 female continental calves were habituated to handling for two weeks prior to bleeding. Calves were blocked on sex, weight and breed of dam and randomly assigned, within block, to either a control (cows remain with calves) or abruptly weaned group (calves removed from cows). Animals were separated into the respective treatment groups at weaning (0 h). Calves were bled at – 168 h, 6 h (males only), 24 h, 48 h and 168 h post weaning. At each sampling time an observer scored the behavioural reaction of calves to sampling. Blood samples were analysed for cortisol, catecholamine concentrations (not sampled at –168 h) and in vitro interferon-gamma production, neutrophil :lymphocyte ratio and acute phase protein concentrations. All continuous data were analysed using a split-plot ANOVA, except that collected at 6 h, which was analysed using a single factor ANOVA model. The effects of weaning, calf sex and time and respective interactions were described. Disruption of the established social groups at 0 h, increased (p<0.001) the plasma cortisol concentration and neutrophil: lymphocyte ratio and reduced the leukocyte concentration (p<0.001) and the in vitro interferon-gamma response to the mitogen concanavalin-A (p<0.001) and keyhole limpet haemocyanin (p<0.001) for weaned and control animals, when compared with –168h. Plasma adrenaline and noradrenaline concentrations were not affected by group disruption. There was no effect of weaning or sex on calf behavioural reaction to handling during blood sampling. Plasma cortisol and adrenaline concentrations were not affected by weaning or sex. Plasma noradrenaline concentration was influenced by weaning x sex (p<0.05) and time x sex (p<0.05). The response increased for male calves with weaning and increased with each sampling time post weaning. For heifers the response was not affected by weaning and plasma concentrations decreased at 168 h post weaning. There was no effect of weaning or sex on leukocyte concentration. The neutrophils : lymphocyte ration increased post weaning (p<0.01) and was affected by sex (p<0.05). Weaning decreased (p<0.05) the in vitro interferon-gamma response to the antigen KLH. There was a time x weaning x sex (p<0.05) interaction for fibrinogen concentration but no effect of treatment on haptoglobin concentration. Abrupt weaning increased plasma cortisol and nor-adrenaline concentrations, which was accompanied by attenuation of in vitro interferon gamma production to novel mitogen and antigen complexes up to 7 days post weaning.European Union Structural Funds (EAGGF

Physiological and behavioural aspects of housing stress in cattle

End of project reportThe effect of various space allowances on pituitary, adrenal, immune responses and performance was investigated in 72 Holstein x Friesian bulls. Bulls (403 ± 3.5 kg) were blocked by weight and randomly assigned into two groups (familiar, F and unfamiliar, UF) x three (1.2, 2.7 and 4.2 m2 per bull; n = 24 bulls per space allowance) treatments and housed for 83 days in 18 pens (n = 4 per pen). Blood samples were collected on day –1, 0, 3, 14, 36 and 77 with respect to mixing and housing on day 0. The bulls were administered with adrenocorticotrophic hormone (ACTH) on day 3 and corticotrophin-releasing hormone (CRH) on days 14, 36 and 77. The basal cortisol concentrations were not affected (P>0.05) by mixing of familiar and unfamiliar bulls. On day 3, basal cortisol was greater (P0.05) of treatment and treatment x time on ACTH. On day 14, interferon-? production was lower (P0.05) different for those housed at 1.2 m2. Bulls housed at either space allowances had (P<0.05) neutrophilia, lymphopenia, eosinopenia and decreased haemoglobin on day 3 compared with day 0. The liveweight gain from days 0 to 83 was lower (P< 0.05) in bulls housed at 1.2 compared with those at 2.7 and 4.2 m2. Housing bulls at 1.2 m2 space allowance had a detrimental effect on their growth and was associated with an acute rise in plasma cortisol concentration (on day 3) compared with space allowances of 2.7 and 4.2 m2/bull.European Union Structural Funds (EAGGF

Cow serum and colostrum immunoglobulin (IgG1) concentration of five suckler cow breed types and subsequent immune status of their calves

peer-reviewedB. Murphy would like to gratefully acknowledge receipt of a Walsh Fellowship provided by Teagasc.The objective of this study was to determine the effect of cow breed type on (a) cow serum and colostrum immunoglobulin (IgG1) concentrations and (b) subsequent calf serum IgG1 concentration and zinc sulphate turbidity (ZST) units. Five cow breed types were examined: LF (Limousin × Friesian), LLF (Limousin × (Limousin × Friesian)), L (Limousin), C (Charolais) and SLF (Simmental × (Limousin × Friesian)). Three blood samples were taken by jugular venipuncture from the cows at approximately 90, 60 and 30 days pre partum, at parturition and at 15 days or more post partum and from the calves at 48 (40 to 56) h post partum. Prior to suckling a 20 ml sample of colostrum was obtained. Milk yield was estimated using the weigh-suckleweigh technique. The decrease in serum IgG1 concentration in cows between 90 days pre partum and parturition was greater (P < 0.01) for LF cows than all other breed types, except SLF. There was no difference between LLF, L, C and SLF cows. There was no effect of cow breed type on colostrum IgG1 concentration. Milk yield was higher (P < 0.001) for LF cows than all other breed types, while that of SLF was higher than the three remaining breed types, which were similar. Calf serum IgG1 concentration and ZST units were higher (P < 0.01) for the progeny of LF cows than all others except SLF. There was no difference between the progeny of LLF, L, C and SLF cows. Calf serum IgG1 was affected by cow breed type and showed a positive relationship with cow serum IgG1 decreases in late pregnancy

A study of the somatic cell count (SCC) of Irish milk from herd management and environmental perspectives

End of project reportThe objective of this study was to investigate the herd management practices associated with somatic cell count (SCC) and total bacteria count (TBC), to geographically analyse SCC on a national basis, to investigate cow factors associated with SCC and to estimate the milk loss associated with high SCC across parities. From the 400 farms surveyed during farm visits throughout spring and winter, a profile of herd management was developed and the associations between management practices and milk SCC and TBC were established. Management practices associated with low SCC included the use of dry cow therapy, participation in a milk recording scheme, the use of teat disinfection post-milking, a higher frequency of cleaning and increased farm hygiene. Management practices associated with low TBC included the use of heated water in the milking parlour, participation in a milk recording scheme, tail clipping of cows at a frequency greater than once per year and increased farm hygiene. The spatial analysis showed that the south of the country had the greatest density of milk-recording herds. Approximately 60% of all herds in the study were from four counties (Cork, Kerry, Limerick and Tipperary). Average bulk tank SCC increased from 110,264 cells/mL in 2003 to 118,782 cells/mL in 2005, followed by a decrease to 108,454 cells/mL in 2007. Spatial clustering of high SCC scores was not observed (i.e., SCC on one farm was not related to SCC on other farms), which is consistent with mastitis being a herd problem as opposed to an area-based problem. SCC increased with parity from 97,000 cells/mL in parity 1 to 199,000 cell/mL in parity 6. SCC decreased between the period 5 to 35 days in milk (DIM) and 36 to 65 DIM, and increased thereafter. Cows calving in the months of January and September were associated with lower average 305 day SCC. The rate of increase in SCC from mid to late lactation was greatest in older parity animals. There was a test day milk loss of 1.43, 2.08, 2.59, 2.56 and 2.62 litres (parities 1 to 5, respectively) associated with an increase of SCC category from 400,000 cells/mL. When SCC was adjusted (test day SCC/dilution estimate, and test day SCC + (-ß)(test day milk yield)) to account for milk yield, similar trends in milk loss were observed. Alternatively, adjusting SCC (SCC*test day milk yield/mean test day milk yield) to account for milk yield showed an increase in test day milk with increasing SCC category. The results from this study highlight that adherence to best milking/farming practice will help reduce SCC and TBC on farms. The results contribute to the knowledge relating to SCC through increasing the accuracy of milk loss due to SCC and management practices associated with SCC. The results in the study can also be used in the development of strategies to reduce SCC on farms

Horizontal transmission of Escherichia coli O157:H7 during cattle housing, survival kinetics in feces and water of Escherichia coli O157:H7 and characterisation of E. coli O157:H7 isolates from cattle faeces and a feedlot environment

End of project reportTeagasc acknowledges with gratitude the support of European Union Structural Funds (EAGGF) in financing this research projectEscherichia coli O157:H7 can cause severe illness and in some cases leading to death. Cattle are the main reservoir with transmission to humans occurring through contamination of food or the environment. Improved understanding of the survival and transmission and survival of E. coli O157:H7 on the farm is essential for developing future controls of this pathogen. This study showed that transmission of E. coli O157:H7 can occur rapidly in groups of housed cattle, with contamination of the pens and hides occurring in 24 hrs. The inoculation dose for cattle is lower than previously reported. Ingestion of bacteria from the hide through social grooming is important for pathogen transmission in housed cattle along with faecal contamination of the environment. Sampling hide will improve the estimation of prevalence of E. coli O157:H7 in pens

Non-alcoholic fatty liver disease short food frequency questionnaire (version 1.0)

A short food frequency questionnaire (SFFQ) to assess habitual intakes of food items related to non-alcoholic fatty liver disease (NAFLD)