Changes in ultrasound measures of muscle and its genetic variation during lactation in dairy cows

2004 ◽  
Vol 79 (3) ◽  
pp. 365-372 ◽  
Author(s):  
K. Sloniewski ◽  
I. L. Mao ◽  
J. Jensen ◽  
P. Madsen

AbstractChanges in ultrasound measures of muscle area (UtM) during lactation in different breeds and parities and with different feeding levels were examined. Random regressions were fitted to repeated measures of UtM in order to study changes in variance components of UtM during lactation. Correlations between measures taken in different stages of lactation and in different parities were also calculated. The shape of UtM curves during lactation appeared to be fairly consistent for all breeds and parities. The lowest point of all curves coincided with the expected nadir of body reserves during lactation. With lower-than-normal feeding level, the drop of UtM after calving was deeper and the overall level was lower. A major proportion of the variance in UtM was found to be determined by additive genetic variation. In all three breeds studied, repeatability and heritability estimates were high and fairly consistent during lactation and between parities. The very high genetic correlations between measures taken in different periods of lactation suggested that muscle growth and recovery are controlled by the same gene complex throughout lactation.Our results suggest that UtM, if used jointly with other body measures such as body condition score, could be a useful indicator of tissue mobilization and deposition in the lactating cow, especially during the early stage of lactation.

2018 ◽  
Vol 58 (1) ◽  
pp. 145 ◽  
Author(s):  
K. A. Donoghue ◽  
S. J. Lee ◽  
P. F. Parnell ◽  
W. S. Pitchford

The genetics of body composition traits measured before calving and at weaning in the first and second parities were evaluated in 5975 Angus and 1785 Hereford cows. Traits measured were liveweight, body condition score and hip height and ultrasound scanned measurements of subcutaneous P8 and 12/13th rib fat depth, loin eye muscle area and intramuscular fat percentage. Corresponding yearling measures on these animals were obtained for analyses of relationships between yearling information with later-in-life traits. There was moderate genetic variation in all body composition traits measured at pre-calving and weaning in Angus (h2 = 0.14–0.59) and Hereford (h2 = 0.14–0.64) cows. Genetic correlations between measurements of the same trait at pre-calving and weaning were consistently positive and high in both parities for both breeds, indicating animals were ranking similarly for the same trait measured over time. Genetic correlations between measurements of different traits were generally consistent over time (pre-calving and weaning) in both breeds, indicating genetic relationships between traits were not changing significantly over time. Genetic correlations with corresponding yearling measures of body composition were consistently positive and high for the first parity, and lower for the second parity. The results of this study indicate that genetic improvement in body composition traits in cows is possible, and that body composition information recorded at yearling age is a reasonably good predictor of later in life performance for these traits.


2014 ◽  
Vol 54 (1) ◽  
pp. 37 ◽  
Author(s):  
M. L. Wolcott ◽  
D. J. Johnston ◽  
S. A. Barwick ◽  
N. J. Corbet ◽  
P. J. Williams

The genetics of cow growth and body composition traits, measured before first calving (pre-calving: in females before calving following their first 3-month annual mating period, at an average age of 34 months) and at the start of the subsequent mating period (Mating 2: on average 109 days later), were evaluated in 1016 Brahman (BRAH) and 1094 Tropical Composite (TCOMP) cows. Measurements analysed were liveweight, ultrasound-scanned measurements of P8 and 12/13th rib fat depth and eye muscle area, body condition score and hip height. Traits describing the change in these from pre-calving to Mating 2 were also included in the analysis. The maternal genetic component of weaning weight was estimated from weaning-weight records on these cows, their steer half-sibs and their progeny generated from up to six matings (n = 12 528). Within pregnant cows at pre-calving, BRAH were significantly lighter, leaner at the P8 site and taller than their TCOMP contemporaries, and these differences were also significant at Mating 2. There was a genetic basis for variation in growth and body composition traits measured at pre-calving and Mating 2 in BRAH (h2 = 0.27–0.67) and TCOMP (h2 = 0.25–0.87). Traits describing the change from pre- calving to Mating 2 were also moderately heritable for both genotypes (h2 = 0.17–0.54), except for change in hip height (h2 = 0.00 and 0.10 for BRAH and TCOMP, respectively). Genetic correlations between measurements of the same trait at pre-calving and Mating 2 were consistently positive and strong (rg = 0.75–0.98) and similar for both genotypes. In lactating cows, genetic correlations of growth and body composition traits with their change from pre-calving to Mating 2 showed that when animals had low levels of P8 and rib fat at Mating 2, change in eye muscle area was an important descriptor of genetic body condition score (rg = 0.63). This was supported by moderate genetic relationships, which suggested that lactating cows that were genetically predisposed to lose less eye muscle area were those that ended the period with higher P8 fat (rg = 0.66), rib fat (rg = 0.72) and body condition score (rg = 0.61). Change in liveweight, body condition score and, in particular, eye muscle area was significantly related to the maternal genetic component of weaning weight (rg = from –0.40 to –0.85) in both genotypes, suggesting that cows with higher genetic milk-production potential were those with the propensity for greater loss of these traits over the period from pre-calving to Mating 2. These results showed that for tropically adapted cows, the change in eye muscle area from pre-calving to Mating 2 was a more important descriptor of body condition at Mating 2 than was change in fat depth, and that higher genetic milk-production potential, measured as maternal weaning weight, was genetically related to higher mobilisation of muscle, and therefore body condition, over this period.


2009 ◽  
Vol 49 (6) ◽  
pp. 399 ◽  
Author(s):  
D. J. Johnston ◽  
S. A. Barwick ◽  
N. J. Corbet ◽  
G. Fordyce ◽  
R. G. Holroyd ◽  
...  

A total of 2115 heifers from two tropical genotypes (1007 Brahman and 1108 Tropical Composite) raised in four locations in northern Australia were ovarian-scanned every 4–6 weeks to determine the age at the first-observed corpus luteum (CL) and this was used to define the age at puberty for each heifer. Other traits recorded at each time of ovarian scanning were liveweight, fat depths and body condition score. Reproductive tract size was measured close to the start of the first joining period. Results showed significant effects of location and birth month on the age at first CL and associated puberty traits. Genotypes did not differ significantly for the age or weight at first CL; however, Brahman were fatter at first CL and had a small reproductive tract size compared with that of Tropical Composite. Genetic analyses estimated the age at first CL to be moderately to highly heritable for Brahman (0.57) and Tropical Composite (0.52). The associated traits were also moderately heritable, except for reproductive tract size in Brahmans (0.03) and for Tropical Composite, the presence of an observed CL on the scanning day closest to the start of joining (0.07). Genetic correlations among puberty traits were mostly moderate to high and generally larger in magnitude for Brahman than for Tropical Composite. Genetic correlations between the age at CL and heifer- and steer-production traits showed important genotype differences. For Tropical Composite, the age at CL was negatively correlated with the heifer growth rate in their first postweaning wet season (–0.40) and carcass marbling score (–0.49), but was positively correlated with carcass P8 fat depth (0.43). For Brahman, the age at CL was moderately negatively genetically correlated with heifer measures of bodyweight, fatness, body condition score and IGF-I, in both their first postweaning wet and second dry seasons, but was positively correlated with the dry-season growth rate. For Brahman, genetic correlations between the age at CL and steer traits showed possible antagonisms with feedlot residual feed intake (–0.60) and meat colour (0.73). Selection can be used to change the heifer age at puberty in both genotypes, with few major antagonisms with steer- and heifer-production traits.


2009 ◽  
Vol 49 (6) ◽  
pp. 413 ◽  
Author(s):  
K. C. Prayaga ◽  
N. J. Corbet ◽  
D. J. Johnston ◽  
M. L. Wolcott ◽  
G. Fordyce ◽  
...  

Genetic analyses of tropical adaptive traits were conducted for two tropically adapted genotypes, Brahman (BRAH) and Tropical Composite (TCOMP). Traits included tick scores (TICK), faecal egg counts (EPG), buffalo fly-lesion scores (FLY), rectal temperatures under hot conditions (TEMP), coat scores (COAT), coat colour on a light to dark scale (COLOUR), navel scores (NAVEL) and temperament measured as flight time (FT). The data comprised adaptive measures recorded at specific times on 2071 heifers comprising 966 BRAH and 1105 TCOMP. The genetic correlations of these adaptive traits with heifer growth, scanned carcass, pubertal measures and steer growth and carcass traits were estimated. BRAH recorded significantly (P < 0.05) lower TICK, EPG, FLY and TEMP than did TCOMP. BRAH also had significantly sleeker coats, lighter coat colour, more pendulous navels and more docile temperament than did TCOMP. The heritability of TICK and FLY was low (<20%), that of EPG, TEMP, NAVEL and FT was moderate (20–50%) and that of COAT and COLOUR high (>50%). In general, phenotypic correlations between these adaptive traits were low and genetic correlations were non-significant, implying trait independence. Genetic correlations between EPG and weight traits (0.29 to 0.44) indicated a positive relationship, implying no deleterious effect of worms on the growth at a genetic level, especially in TCOMP. The negative genetic correlations between COAT and body-condition score across genotypes (–0.33 to –0.48) indicated genetic advantage of sleek coats in tropics. A positive genetic correlation between COAT and the age at the first-observed corpus luteum (0.73) in BRAH indicated that BRAH with sleeker coats were genetically early maturing. Further, sleeker coats were genetically indicative of lower weights and lower fat cover at puberty in BRAH. The scanned fat measures at rump and rib sites for feedlot steers showed strong genetic correlation (0.50–0.58) with heifer TEMP, indicating genetically fatter animals had genetically lower heat tolerance. In BRAH, a positive genetic association between heifer COLOUR and scanned fat measures in steers (0.50–0.54) implied increased fatness in genetically darker animals. Further, in BRAH, a strong negative genetic correlation (–0.97) was observed between steer retail beef yield and heifer TEMP, indicating a favourable genetic association. In general, genetic correlations between adaptive traits and other economic traits were genotype specific. Further, it can be concluded that selection for productive and pubertal traits in tropical beef cattle genotypes would not adversely affect their tropical adaptability.


2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 75-75
Author(s):  
Kailey Bradley ◽  
Brooke Boyd ◽  
Lindsay Garrison ◽  
Morgan Higgins ◽  
Robert Newton ◽  
...  

Abstract Impact of grazing method on ewe performance, parasite infestation, and soil was examined using mature, non-lactating ewes divided into slow rotation (SR; n = 20) or daily rotation (DR; n = 20) groups. Pastures previously grazed by sheep were divided and soil sampled. Temporary electric fence provided daily pasture allocation for DR. Ewes had been adapted to temporary electric fence for two weeks. Both DR and SR were moved to new pasture at the same time. Ewes were weighed and fecal egg counts were conducted biweekly. On alternate weeks, ewes were body condition scored (BCS), FAMACHA scored, and dewormed if FAMACHA score was 4 or greater. After 10 weeks of grazing (June 1-August 10, 2018), final ewe weights and soil samples were collected. Body condition score, FAMACHA, fecal egg count, body weight, and soil test results were tested for effect of grazing group, date, and group by date interaction using procedures for repeated measures with JMP software (version 10, SAS Inst. Inc., Cary, NC). The FAMACHA scores were greatest on July 6 (P < 0.0001). BCS were greater on June 8 and 22 than July 6 and August 3 (P < 0.0001). Ewes were heaviest on June 1 and 15, lightest on July 27 and August 10 (P < 0.0001), and DR ewes were lighter than SR ewes on July 27 and August 10 (P < 0.0001). No effect of treatment, date, or treatment by date interaction on fecal egg count (P > 0.23) was detected. Soil organic matter decreased over the study (P = 0.0024), but organic matter change was less in DR than SR (P = 0.0092). DR did not influence parasitism, but may enhance soil organic matter.


2019 ◽  
Vol 59 (7) ◽  
pp. 1209 ◽  
Author(s):  
Viviane V. de Lacerda ◽  
Gabriel S. Campos ◽  
Daniel D. Silveira ◽  
Vanerlei M. Roso ◽  
Mario L. Santana ◽  
...  

The size and body condition of female livestock is critical for improving production efficiency. However, we know little about how height and body condition score in mature beef cattle are genetically related to traits observed when the animals are younger. In the present study, we used data from 321650 Nelore cattle, first, to compare genetic parameters and breeding values on the basis of different models employing weight (MW), height (MH) and body condition score (BCS) of mature cows (3–17 years old). Next, we estimated the genetic correlations between the three traits and assorted yearling traits (YW, weight; YC; conformation score; YP, precocity score; YM, muscling score; YN, navel score; LMA, longissimus muscle area; BF, back fat thickness). Finally, we obtained the expected direct responses to selection for MW, MH and BCS of cows and correlated responses for these traits when the selection was applied to yearling traits. For MW and MH, single-trait Bayesian analyses were used to evaluate the effects of including BCS when defining contemporary groups (BCS included, CG1; BCS not included, CG2). For BCS trait, linear and threshold animal models were compared. After, bi-trait analyses that included MW, MH or BCS with yearling traits were performed. The CG1 scenario resulted in a higher heritability for MW (0.45 ± 0.02) than did CG2 (0.39 ± 0.02). Both scenarios yielded the same heritability estimates for MH (0.35 ± 0.02). Sires’ rank correlations between predicted breeding values under CG1 and CG2 were 0.60–0.92 for MW and 0.90–0.98 for MH, considering different selection intensities. Thus, only for MW genetic evaluations, the incorporation of BCS in the definition of the contemporary groups is indicated. For BCS trait, the same sires were selected regardless of the model (linear or threshold). Genetic correlations between MW and five yearling traits (YW, YC, YP, YM and YN) ranged from 0.18 ± 0.03 to 0.84 ± 0.01. The MH had a higher and positive genetic association with YW (0.64 ± 0.02) and YC (0.54 ± 0.03), than with YN (0.18 ± 0.03). However, MH was negatively and lowly genetically correlated with YP (–0.08 ± 0.03) and YM (–0.14 ± 0.03). The BCS had positive genetic associations with all yearling traits, particularly with YP (0.61 ± 0.06) and YM (0.60 ± 0.07). Mature size and carcass traits exhibited a low to moderate negative genetic correlations. However, BCS had positive genetic associations with LMA (0.38 ± 0.12) and BF (0.32 ± 0.14). Despite a shorter generation interval, selection at the yearling stage will result in a slower genetic progress per generation than does direct selection for cow MW, MH or BCS. Moreover, using YW and YC as selection criteria will increase cattle size at maturity without altering BCS. Last, LMA or BF-based selection will reduce mature size, while improving BCS, as a correlated response.


1970 ◽  
Vol 33 (8) ◽  
pp. 339-342 ◽  
Author(s):  
M. J. Ortiz ◽  
E. M. Kesler ◽  
G. H. Watrous ◽  
W. H. Cloninger

An objective of this study was to investigate the relationship between body condition of the dairy cow and susceptibility of milk to rancidity. Initial milk samples were obtained from 166 cows in Spring, 1969, and all animals were retested after an interval of two months. Additional observations included the effects of stage of lactation, level of milk production, and herd effects. Each cow was evaluated for body condition, at the times when milk samples were obtained, by a method based on measures of weight and skeletal size and by a subjective scoring system. Spontaneous rancidity of the milk fat was allowed to develop upon storage for 48 hr; and induced rancidity was brought about by controlled agitation. As measured by acid degree values (ADV) the treatments imposed on the milk samples were successful in simulating development of spontaneous and induced lipolysis of the milk fat. However, the magnitude of the ADV was not related to body condition score. It is concluded that in well-fed herds, such as those used in this experiment, body condition of the cow does not influence the susceptibility of her milk to rancidity. These data may not apply under conditions of poor feeding and management. Advancing stage of lactation was associated with increases in both spontaneous and induced rancidity. This was indicated by positive correlations between days in milk and ADV, and by significantly higher values in the second sampling period than in the first. There was a negative correlation between the amount of milk produced and ADV. This may have been related to the decline in milk flow which accompanied advancing lactation. An unexplained herd difference existed with respect to the susceptibility of milk to induced rancidity.


2016 ◽  
Vol 83 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Torben Larsen ◽  
Lene Alstrup ◽  
Martin Riis Weisbjerg

The present study was conducted in order to investigate if selected minor milk components would be indicative for the nutritional situation of the cow. Forty-eight dairy cows were offered a high digestible ration vs. a lower digestible ration combined with 2 protein levels in a 4 × 4 Latin square design. Milk glucose, glucose-6-phosphate, cholesterol, triacylglycerides (TAG), uric acid and β-hydroxybutyrate (BHBA) were measured and correlated mutually and towards other milking parameters (yield, h since last milking, days in milk (DIM), urea, etc). The variation range of the suggested variables were broad, a fact that may support their utilisation as predictive parameters. The content of milk metabolites was significantly affected by the change in rations as milk glucose, glucose-6-phosphate, uric acid, and the ratio cholesterol: triacylglycerides increased with higher energy intake while BHBA and TAG decreased. The content of some of the milk metabolites changed during 24 h day/night periods: BHBA, cholesterol, uric acid and TAG increased whereas free glucose decreased in the night period. Certain associations between milk metabolites and calculated energy parameters like ECM, body condition score (BCS), and body weight gain were found, however, these associations were to some extent explained by an interaction with DIM, just as changes in milk metabolites during a 24 h period seems to interfere. It is concluded that the practical use of the suggested milk variables should be based on more than one metabolite and that stage of lactation and possibly time of the day where the milk is collected should be incorporated in predictive models.


1993 ◽  
Vol 73 (1) ◽  
pp. 67-77 ◽  
Author(s):  
E. Charmley ◽  
P. H. Robinson ◽  
R. E. McQueen

Twelve multiparous and three primiparous cows were used in a 10-wk lactation study with two repeated measures to evaluate diets containing 90% timothy–alfalfa silage (TA), 84% corn silage (CS) or an equal mixture of each (TA–CS). Each diet was supplemented with minerals to meet requirements; barley was used as a carrier. Diets CS and TA–CS were also supplemented with urea, casein and soybean meal, making them similar to TA for undegraded intake protein (UIP) and degraded intake protein (DIP) levels. Two of the cows on each treatment were fitted with a ruminal cannula. There were no treatment effects on intake (27 g DM kg−1 BW), body-weight change or body-condition score. Milk yield averaged 15.3 kg d−1 and was not treatment influenced (P > 0.05); however, yield of fat and protein and percentage of lactose in milk showed a linear response to increased corn silage in the diet (P < 0.05). Rumen pH was least and rumen ammonia concentration greatest in the mixed silage diet (P < 0.05). Rumen pool sizes of organic matter and neutral detergent fiber were not treatment influenced (P > 0.05). All treatments supported modest levels of production for cows in late lactation, with increasing dietary energy density from corn silage increasing energy output in milk. Key words: Dairy cow, silage diets, forage species, milk production


Author(s):  
A.J. Chay-Canul, R. A. Garcia- Herrera, N. F. O. Robertos ◽  
Ulises Macias- Cruz ◽  
Ricardo Vicente- Pérez ◽  
Víctor M. Meza- Villalvazo

Abstract 


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