Comparative grazing behaviour of lactating suckler cows of contrasting genetic merit and genotype

Abstract

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  Genotype had no effect on any recorded grazing behaviour variables  High genetic merit cows grazed for longer with more bites but had a lower grass dry matter intake  No significant differences across genetic merit or genotype were observed for rumination measures.  Beef x dairy cows more efficiently convert herbage to milk production than beef

Quantification of cow milk yield and pre-weaning calf growth response in temperate pasture-based beef suckler systems: A meta-analysis

“…The 66 g higher calf pre-weaning ADG from Dairybeef compared to Beef genotypes is in line with results from other studies (72-110 g, McGee et al, 2005;141-205 g, Murphy et al, 2008). The 14 kg heavier calves at weaning (210-day adjusted) from Dairybeef compared to Beef genotypes is in close agreement with a recent analysis of an Irish national database (McCabe et al, 2019b) and a cow genotype evaluation (McCabe et al, 2019a), which found that calves from beef x dairy cows were ca. 18 kg heavier at weaning (240-days) than beef genotypes.…”

“…Milk is the primary source of nutrients for the newborn calf in early postnatal life and remains a significant component of the diet until weaning (McGee et al, 2005;Grings et al, 2008;Roca Fraga et al, 2018). Beef suckler cows with higher milk yield (MY) generally produce heavier calves at weaning (Arthur et al, 1997;Murphy et al, 2008a;Minchin and McGee, 2011;Vaz et al, 2016;McCabe et al, 2019a); MY can account for up to ca. 74% of the variance in calf WW (Arthur et al, 1997).…”

Validation of a beef cattle maternal breeding objective based on a cross-sectional analysis of a large national cattle database

“…Nonetheless, validation of overall breeding objectives, in cattle at least, is not well publicized in the scientific literature (Ramsbottom et al, 2012;Newton et al, 2017;O'Sullivan et al, 2019). To our knowledge, only 1 study has evaluated the impact on phenotypic performance from selection on a maternal breeding objective in cattle and this was a relatively small controlled study undertaken in Ireland (McCabe et al, 2019). McCabe et al (2019) failed to detect a significant difference between a high genetic group (n = 41) and low genetic group (n = 41) for body weight, body condition score, milk yield, and a range of intake traits.…”

“…To our knowledge, only 1 study has evaluated the impact on phenotypic performance from selection on a maternal breeding objective in cattle and this was a relatively small controlled study undertaken in Ireland (McCabe et al, 2019). McCabe et al (2019) failed to detect a significant difference between a high genetic group (n = 41) and low genetic group (n = 41) for body weight, body condition score, milk yield, and a range of intake traits. Although the present study does demonstrate the impact of the maternal index on individual traits, financial information at a herd-level is lacking to truly validate the index.…”

“…Maternal breeding indexes in cattle are not often described in the scientific literature although Roughsedge et al (2005) and Ochsner et al (2017) outlined a maternal beef breeding index for the UK and USA, respectively. Using a relatively small controlled study of 82 beef cows divergent on the Irish national maternal index, McCabe et al (2019) failed to detect a significant difference between the high maternal index group (n = 41) and the low maternal index group (n = 41) for body weight, body condition score, milk yield, and a range of feed intake traits. McHugh et al (2014) evaluated the phenotypic performance of 38,619 beef cattle differing in genetic merit for individual fertility, calving performance, and weaning weight traits.…”