R. Prendiville

A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions

The objective of this study was to investigate the effect of 2 breeds, Holstein and Jersey, and their F(1) hybrid (Jersey x Holstein) on milk fatty acid (FA) concentrations under grazing conditions, especially conjugated linoleic acid (CLA) and n-3 polyunsaturated fatty acids because of their importance to human health. Eighty-one cows (27 per breed grouping) were allocated a predominantly perennial ryegrass pasture. Samples were collected over 2 periods (June and July). Breed affected dry matter intake and milk production and composition. Holstein cows had the highest dry matter intake (18.4+/-0.40kg of DM/d) and milk production (21.1+/-0.53kg of DM/d). Holstein and Jersey x Holstein cows had similar 4% fat corrected milk, fat yield, and protein yield; with the exception of fat yield, these were all higher than for Jersey cows. Milk fat concentration was highest for Jersey cows and lowest for Holstein cows, with the hybrid cows intermediate. Total FA and linolenic acid intake (1.09+/-0.023 and 0.58+/-0.012 kg/d, respectively) were highest for Holstein cows. In terms of milk FA, Holstein cows had higher contents of C14:1, cis-9 C18:1 and linoleic acid. In turn, Jersey and Jersey x Holstein cows had higher content of C16:0. Milk concentrations of neither the cis-9,trans-11 isomer of CLA nor its precursor, vaccenic acid, were affected by breed. Nevertheless, large variation between individual animals within breed grouping was observed for CLA and estimated Delta(9)-desaturase activity. There was some evidence for a negative heterotic effect on milk concentration of CLA, with the F(1) hybrid cows having lower concentrations compared with the mid parent average. Plasma FA profile did not accurately reflect differences in milk FA composition. In conclusion, there was little evidence for either breed or beneficial heterotic effects on milk FA content with human health-promoting potential, though significant within-breed, interanimal variation was observed.

Comparative grazing behavior of lactating Holstein-Friesian, Jersey, and Jersey × Holstein-Friesian dairy cows and its association with intake capacity and production efficiency

The objectives of this study were to investigate differences in grazing behavior among Holstein-Friesian (HF), Jersey (JE), and Jersey x Holstein-Friesian (F(1)) cows under an intensive, seasonal, grass-based environment and to determine whether associations exist among grazing behavior, intake capacity, and production efficiency. Data from a total of 108 animals (37 HF, 34 JE, and 37F(1)) were available for analysis. Measurements included milk production, body weight (BW), intake, and grazing behavior. Breed group had a significant effect on all of the production, grass dry matter intake, and efficiency parameters investigated. No differences were observed among the breeds for grazing time, number of grazing bouts, grazing bout duration, and total number of bites. Grazing mastications were higher for the JE cows compared with the HF cows. Grass dry matter intake per bite and rate of intake per minute were higher for the HF cows compared with the JE cows. Large differences between the breeds were apparent when grazing behavior measurements were expressed per unit of BW and per unit of intake. In absolute terms, the HF cows spent more time ruminating and had more mastications during rumination than the JE cows. However, when expressed per unit of BW, ruminating time was greater for the JE cows and they tended to have more ruminating mastications compared with the HF cows. Despite these differences, ruminating time and ruminating mastications per unit of intake were similar for the 2 breeds. For the most part, the F(1) cows tended to be similar to the mid-parent mean, but results showed an increase in biting rate, lower grazing duration per bout, and a tendency to achieve a high intake per bite compared with the average of the parent breeds. The results obtained also indicate that inherent grazing and ruminating differences exist between cows varying in intake capacity and production efficiency. Cows with higher intake capacities have increased grazing time and rate of intake per unit of BW. Increased production efficiency, on the other hand, appears to be aided, in particular by improvements in mastication behavior during grazing.

A comparison between Holstein-Friesian and Jersey dairy cows and their F1 cross with regard to milk yield, somatic cell score, mastitis, and milking characteristics under grazing conditions

The key objectives of this study were to investigate differences in milking characteristics and udder health between Holstein-Friesian (HF), Jersey (J), and Jersey x Holstein-Friesian (F(1)) cows and to determine possible associations between milking characteristics and udder health. Records were available from 329 lactations (162 cows): 65 HF, 48J, and 49F(1). Data included lactation mean milk yield, somatic cell score (SCS), incidence of mastitis, average milk flow (AMF), peak milk flow (PMF), and milking duration (MD). Breed group had a significant effect on milk yield and was higher with the HF cows (18.0 kg/d) compared with the J cows (14.2 kg/d). Udder health (SCS and incidence of mastitis at least once during lactation) were similar across the breed groups. Average milk flow was greater with the HF cows (1.36 kg/min) compared with the J cows (1.09 kg/min). Peak milk flow also tended to greater with the HF cows. No difference in MD was observed between the breed groups. The performance of the F(1) cows tended to be similar to the mid-parent (breed) mean for udder health and MD, but heterosis was evident for milk yield, AMF, and PMF. Correlations examined showed that phenotypic milk yield was negatively associated with SCS. Increased milk yield was synonymous with increased AMF, PMF, and MD. Correlations between SCS and milking characteristics were weak. Correlations also showed that cows with low AMF and PMF had extended MD. Therefore, no difference in udder health was observed between HF, J, or F(1) cows. The fact that higher yielding animals exhibit faster milking speeds was confirmed; however, no difference in MD was observed between the breed groups. Such findings indicate that regularity in the milking process will be maintained within mixed-breed herds.

Expression of genes involved in energy homeostasis in the duodenum and liver of Holstein-Friesian and Jersey cows and their F1 hybrid

Differences in feed intake and production efficiency in lactating Holstein-Friesian (HF), Jersey (JE), and JE × HF (F(1)) dairy cows have been reported. The liver-gut axis is important in the regulation of energy homeostasis, appetite behaviour, and production efficiency. The objectives of this study were to determine: 1) the effect of dairy cow genotype on the expression profiles of genes involved in energy homeostasis in duodenal and hepatic tissue, and 2) the association between the expression of these genes across both tissues and with economically important production efficiency traits. The expression of 27 candidate genes involved in energy homeostasis, feed intake, and energy storage was measured by qPCR. Duodenal expression of the pro-opiomelanocortin (POMC), glucagon-like peptide 1 receptor (GLP1R), and insulin-like growth factor 1 (IGF1) genes was highest in HF. In contrast, hepatic expression of the leptin receptor (LEPR), insulin-like growth factor 1 receptor (IGF1R), protein kinase, AMP-activated, beta 1 (AMPKB1), and POMC genes was highest in the F(1) cross. In the duodenum, positive correlations were observed between mRNA expression of anorectic peptides (POMC and GLP1R), whereas a negative correlation was detected between orexigenic (ghrelin) and anorectic (peptide YY) gene expression. A negative correlation was observed between duodenal POMC gene expression and both residual feed intake and milk production efficiency traits, while GLP1R gene expression was negatively correlated with milk production efficiency traits. A heterotic effect was observed in hepatic expression of AMKPB1, IGF1R, LEPR, POMC in the F(1) genotype, possibly mediating improved feed efficiency in cross-bred cows. In conclusion, key genes involved in energy homeostasis and appetite behaviour are differentially expressed due to cow genotype in a tissue-dependent fashion. POMC and GLP1R are potential candidate genes for the identification of single nucleotide polymorphisms regulating energetic efficiency in the dairy cow, which may be incorporated into future breeding programmes.

Detection of anthelmintic resistance on two Irish beef research farms.

Beef and milk production systems in Ireland are largely dependent on a grass-based diet with cattle spending long periods of the year at pasture (Drennan and McGee 2009). As a result, cattle are frequently exposed to gastrointestinal nematode (GIN) challenge. Within grass-based production systems, anthelmintics are essential to optimising performance and any reduction in their efficacy may lead to reduced animal performance. Although anthelmintic resistance (AR) is more commonly reported in sheep (Sutherland and Leathwick 2011), it has been increasingly reported in cattle worldwide (Stafford and Coles 1999, Loveridge and others 2003, Soutello and others 2007, Demeler and others 2009, Edmonds and others 2010). To date, there have been no published reports of AR in cattle in Ireland. We report the findings of a faecal egg count reduction test (FECRT) conducted at two Irish agricultural research farms (Study A and B). Two different software programmes were used to determine anthelmintic efficacy. All animal procedures performed in this study were conducted under experimental license (B100/2869) from the Irish Department of Health and Children, in accordance with the Cruelty to Animals Act 1876 and the European Communities (Amendment of Cruelty to Animals Act 1876) Regulation 2002 and 2005. Study A was conducted at Teagasc, Johnstown Castle, Wexford, Co. Wexford, Ireland (longitude 6°30′ W; latitude 52°17′ N; …

Physico-chemical and sensory characteristics of young dairy bull beef derived from two breed types across five production systems employing two first season feeding regimes

BACKGROUND The present study aimed to assess the physico-chemical and sensory characteristics of Longissimus thoracis muscle from young dairy bulls: Holstein-Friesian (HF) and Jersey × Holstein-Friesian (JEX). Bulls slaughtered at 15 months of age differed with respect to the finishing system, whereas 19-month-old bulls differed in energy consumption during a second grazing season and finishing period. All bulls were offered different diets during the first grazing season. RESULTS Insoluble and total collagen contents increased with slaughter age, whereas collagen solubility and hue angle reduced with age. Bulls fed a higher concentrate finishing diet held a longer beef flavour. Intramuscular fat (IMF) content and beef flavour score were enhanced by higher concentrate intake during the second season and finishing period. Beef from a higher forage diet displayed a more intense red colour and higher thawing loss. There was limited effect of silage finishing or first and second grazing season on quality traits. Beef from JEX breed had a higher IMF content, higher flavour, juiciness and texture-related scores while lower moisture content compared to HF beef. CONCLUSION The eating quality of beef from young dairy bulls was generally good. Slaughter age and the energy level of diet had obvious effects on quality characteristics. Cross-breeding Jersey with the HF breed can improve the beef quality of young dairy bulls.

Animal performance and economic implications of alternative production systems for dairy bulls slaughtered at 15 months of age

Abstract The objectives of this experiment were to investigate (i) the influence of varying levels of concentrate supplementation during the grazing season, (ii) alternative finishing strategies for dairy bulls slaughtered at 15 mo of age and (iii) economic implications of these management strategies. Bulls were assigned to a 2 (level of concentrate supplementation during the grazing season: 1 kg [LA] and 2 kg [HA] dry matter [DM]/head daily) × 2 (finishing strategies: concentrates ad libitum group [AL] or grass silage ad libitum plus 5 kg DM of concentrates/head daily group [SC]) factorial arrangement of treatments. Average daily gain (ADG) during the grazing season was greater (P < 0.01) for HA than for LA. Consequently, HA bulls were 16 kg heavier at housing: 214 and 230 kg, respectively (P < 0.05). During the finishing period, ADG tended (P = 0.09) to be greater for LA than for HA. Carcass weight tended (P = 0.08) to be greater for HA than for LA. Fat score was greater for HA. Live weight at slaughter (P < 0.001) and carcass weight (P < 0.001) were 41 and 23 kg greater for AL than for SC, respectively. Conformation (P < 0.05) and fat score (P < 0.05) were greater for AL than for SC. The Grange Dairy Beef Systems Model simulated whole-farm system effects of the production systems. Net margin/head was greater for LA than for HA and greater for SC than for AL. Sensitivity analysis of finishing concentrate price, calf purchase price and beef price showed no re-ranking of the systems on a net margin basis. Although greater animal performance was observed from the higher plane of nutrition, overall profitability was lower.

Animal performance and economic implications of Holstein-Friesian, Jersey and Jersey × Holstein-Friesian cows under seasonal pasture based systems

Animal performance and economic implications of Holstein-Friesian, Jersey and Jersey × Holstein-Friesian cows under seasonal pasture based systems R. Prendiville, L. Shalloo, K.M. Pierce, F. Buckley Teagasc, Moorepark, Dairy Production Research Centre, Fermoy, Co. Cork, Ireland School of Agriculture, Food Science and Veterinary Medicine, UCD, Belfield, Dublin 4, Ireland Email: robert.prendiville@teagasc.ie