Validation of Indirect Measures of Body Fat in Lactating Cows

Abstract

The objective of the study was to establish and compare equations that would estimate the body fat content of lactating dairy cows from different indirect techniques. The techniques used were body condition scoring, dilution of D2O in body water, and determination of mean fat cell size diameter of the subcutaneous, abdominal, and perirenal depots. Each technique was validated against direct determination of body fat content of the same lactating cows. To apply equations to high producing, lactating dairy cows, cows were from a herd producing more than 9500 kg of FCM/305 d, were lactating, and were in less than average body condition. Eight days prior to slaughter, a single injection of D2O was injected into the jugular vein, and body dilution was followed for 4 d. Cows were scored for body condition on the day of injection and weighed daily for the 4 d prior to slaughter. Samples of subcutaneous, perirenal, and omental adipose depots were taken, and adipocyte size and number were determined. Body fat was not predicted well by D2O space alone, but inclusion of BW did improve the prediction of body fat from this variable. The best equations were derived from use of BW with body condition score or subcutaneous fat cell diameter: observed body fat = -122.1 + .21 x BW + 36.0 x body condition score, and -195.6 + .290 x BW + .927 x subcutaneous fat cell diameter; standard errors of the estimate were 4.6 and 5.5 kg, respectively. Equations using diameters of abdominal and perirenal fat cells gave similar relationships. Equations using all four predictors (live BW, fat cell diameter, condition score, and D2O space) were only slightly improved over these equations. Thus, use of body condition score, adipocyte diameter, and BW in laboratory and field conditions may help in the study and management of the use of body fat in lactating dairy cows.

Relationship between body condition score and health traits in first-lactation Canadian Holsteins

“…Nevertheless, fewer animals are at the extremes of the BCS scale (Ruegg and Milton, 1995;Roche et al, 2004;Berry et al, 2007), and Schröder and Staufenbiel (2006) summarized from various studies that a 1-unit change in BCS consistently correlated with about 50 kg of empty body fat. Additionally, Waltner et al (1994) reported a strong correlation between BCS and observed body fat. Conversely, other studies have linked the rarity of animals with BCS at the extremes with a reluctance to score near the end points (Kristensen et al, 2006) or a fear of offending the producer (Ward, 2003, as referred to by Bewley and Schutz, 2008).…”

“…Several studies have indicated that, although it is a subjectively measured trait, BCS is accurate enough to explain a large part of the variation in body reserves between animals (Waltner et al, 1994;Enevoldsen and Kristensen, 1997;Gregory et al, 1998). Body condition score meets all the criteria to be considered a useful indicator trait for health and fertility status in dairy cattle.…”

“…Body condition score possesses ample genetic variation throughout lactation to allow for successful selection Berry et al, 2003b;Mao et al, 2004;Loker et al, 2011). Because the body condition can be scored visually on freely moving cattle (Edmonson et al, 1989), it is easy, quick, and inexpensive to measure (Waltner et al, 1994). Last, BCS is moderately to strongly genetically correlated with health (Dechow et al, 2004;Neuenschwander, 2010) and reproduction status (Pryce et al, 2001;Banos and Coffey, 2010;Bastin et al, 2010a,b).…”

Meat quality traits and muscle composition of cows differing in lactation performance

“…As a result of this, and to meet the nutritional demands of milk synthesis, cows need to mobilise body reserves, mainly fat as energy source, until nutrient intake covers the demands (Nebel & McGilliard 1993, Hattan et al 2001, Grummer & Rastani 2003. The study of Waltner et al (1994) showed that fat cell diameter can be sensitive to alterations in lactation rate and stage, being an indicator of fat mobilisation. In high producing dairy cows, muscle degradation and protein catabolism can be involved in restoring energy balance in conjunction with lipolysis and an increase in appetite.…”

Changes of muscle fibre profile and fat cell size around first parturition in cows differing in lactation performance

“…The relationship of fat cell size to body lipid mass is quite strong in lactating cattle (McNamara, 2000). In adult or almost adult ruminants, the majority of changes in magnitude of the subcutaneous adipose depot is due to changes in mean cell size and can therefore be considered as a measure for fat storage or mobilization (Waltner et al, 1994). The study of Waltner et al (1994) showed that fat cell diameter is sensitive to alterations in rate and stage of lactation.…”