scholarly journals Performance of lactating suckler cows of diverse genetic merit and genotype under a seasonal pasture-based system

Author(s):  
S. McCabe ◽  
N. McHugh ◽  
N.E. O’Connell ◽  
R. Prendiville

The objective of this study was to investigate the effect of genetic merit of the national Irish maternal index and genotype (i.e. beef vs. beef × dairy [BDX]) of beef cows and subsequent performance of their progeny. With the exception that high genetic merit cows produced 0.57 kg more milk and tended to have 0.04 of a lower body condition score (BCS), no significant differences were observed between cows of diverse genetic merit. Differences between contrasting cow genotype were apparent. Beef cows were 50 kg heavier and had a BCS 0.27 greater than BDX cows. The BDX cows produced 1.67 kg more milk and had a greater 24-d submission rate than beef cows. Calves generated from BDX cows were 19 kg heavier at weaning and were worth €51 more than progeny generated from beef cows. Beef cow progeny, however, had 0.77 of a greater conformation score at slaughter than BDX. While differences were observed across cows of different replacement strategies, results from the current study showed that genetic selection for national maternal index had no effect on the overall performance of suckler cows in a pasture-based spring-calving system.

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 22-22
Author(s):  
Amanda Holder ◽  
Aksel Wiseman ◽  
Adam McGee ◽  
David Lalman ◽  
Claire Andresen

Abstract Several factors influence the overall maintenance requirements of a mature beef cow including age, gain, lactation, pregnancy, and fleshing ability. However, limited research is available to distinguish what sets a hard-fleshing cow apart from an easy-fleshing cow. Cows that are hard-fleshing maintain a lower body condition score (BCS) throughout the year compared to easy-fleshing counterparts. The objectives of this experiment are to determine the differences in characteristics and production between cows classified as easy- vs. hard- fleshing. Characteristics of interest include feed intake, milk yield, milk composition, body weight changes, BCS changes, and other body composition measurements, as well as calf weaning weight. In this study, 24 spring-calving, mature Angus beef cows were classified as either hard-fleshing or easy-fleshing based on BCS and ultrasound measurements for back fat and rump fat. The intake study took place during the second trimester, cows were assigned to an easy- or hard-fleshing pen based on treatment where they remained for the entirety of the 45-day intake study. Each treatment was replicated three times in a completely randomized design. Milk data collection began one month after calving with monthly milkings from May-August. There were no differences (P = 0.9) in DMI, although hard-fleshing cows had greater DMI calculated on a metabolic body weight basis (P = 0.05). There was a trend (P = 0.12) for hard-fleshing cows to wean heavier calves, although there was no difference in mean milk yield (P = 0.44). Body condition score was positively correlated with protein and carbohydrate content of milk with easy-fleshing cows having greater contents of both (P = 0.02 and P < 0.01, respectively). Overall, an increase in BCS without an increase in DMI may be beneficial from a reproductive standpoint, though more research in this area is needed.


1999 ◽  
Vol 24 ◽  
pp. 119-127 ◽  
Author(s):  
J. E. Pryce ◽  
P. Løvendahl

AbstractGenetic selection for milk production has been very successful. However to achieve high yields, the metabolic load on dairy cows is believed to be substantial. If the size of this load is large enough then the animal may become ‘metabolically stressed’. Signs of this may include some sort of distortion of normal physiological function. There is evidence from both population studies and research herds to suggest that intense selection for milk yield has led to a deterioration in some aspects of health and fertility. Genetic correlation estimates between production and measures of fertility are unfavourable. As an example, calving intervals of high merit animals from Langhill are on average 12 days longer than those of average genetic merit, which is mostly due to a delay in days to first heat. It is suggested that some aspects of health and fertility problems in high genetic merit animals are a consequence, in part, of so-called metabolic stress. Future breeding goals should be broadened to include a broad spectrum of traits related to efficient milk production, in addition to either health and fertility traits themselves, or traits believed to be precursors of them, such as those related to metabolic stress. The complexity and subjectivity of metabolic stress and its components makes it very difficult to include in future breeding goals. However, traits related to energy balance, such as some measures of condition score, dry-matter intake and live weight may be useful in breeding programmes where one of the goals is to alleviate metabolic stress.


1986 ◽  
Vol 43 (3) ◽  
pp. 391-396 ◽  
Author(s):  
I. A. Wright ◽  
A. J. F. Russel ◽  
E. A. Hunter

ABSTRACTForty-eight Hereford × Friesian and Blue Grey cows ranging in body condition score from 1·75 to 4·0, 12 weeks before calving, were fed to achieve three levels of body condition score at calving. Half the cows were fed on an increasing plane of nutrition as pregnancy advanced and half were fed on a flat-rate feeding system. The condition scores achieved by the three groups at calving were 2·28, 2·47 and 2·70 (s.e.d. 0·071; P < 0·001). Differences in cow body condition at calving were reflected in cow live weight and condition 6 weeks later, but there was no effect on calf performance. Hereford × Friesian cows lost more weight in early lactation, tended to produce more milk and their calves were heavier. Pattern of feeding had no effect on cow condition score or weight at calving or on subsequent performance.It was calculated that each unit of body condition-score loss in late pregnancy contributes the equivalent of 3200 MJ dietary metabolizable energy while 6600 MJ dietary metabolizable energy are required for 1 unit of condition-score gain.


2017 ◽  
Vol 8 (s1) ◽  
pp. s55-s59 ◽  
Author(s):  
S. McCabe ◽  
N. McHugh ◽  
R. Prendiville

This study aimed to determine estimates of production efficiency among primiparous suckler cows of diverse genetic merit (GM) for the national Irish maternal index. Data from 82 heifers of diverse GM across two different replacement strategies (suckler (S) or dairy (D) sourced) were available. Milk yield, grass dry matter intake, cow BW and body condition score (BCS) were recorded. The maternal index had no significant effect on any parameters investigated, whereas S cows were 86 kg heavier in BW, had a 0.33 greater BCS and 0.6 UFL greater NEM requirement compared with D beef crossbred (F1) cows. The F1 produced 2.2 kg/day more milk and had greater lactation energy requirements (0.8 UFL) than S. The F1 produced 0.48 kg milk per 100 kg BW and 0.15 kg more milk per unit intake. An interaction between GM and cow origin (CO) showed that F1 low merit cows consumed an additional 1 kg DM than F1 high, and that S high merit cows produced 1.5 kg less milk than their S low counterparts resulting in a 0.5 UFL greater energy requirement for milk production for S low. The F1 high merit cows produced 0.12 kg more milk per unit intake than F1 low cows, whereas S low cows produced 0.12 kg less milk per unit intake than S high. The F1 low cows consumed 0.17 kg more DM per unit BW than F1 high. Thus, genetic selection for maternal traits has not resulted in differences in production efficiency traits, however CO differences were observed.


2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 62-62
Author(s):  
Amanda Holder ◽  
Aksel Wiseman ◽  
Adam McGee ◽  
David Lalman ◽  
Claire Andresen

Abstract Several factors influence the overall maintenance requirements of a mature beef cow including age, gain, lactation, pregnancy, and fleshing ability. However, limited research is available to distinguish what sets a hard-fleshing cow apart from an easy-fleshing cow. Cows that are hard-fleshing maintain a lower body condition score (BCS) throughout the year compared to easy-fleshing counterparts. The objectives of this experiment are to determine the differences in characteristics and production between cows classified as easy- vs. hard- fleshing. Characteristics of interest include feed intake, milk yield, milk composition, body weight changes, BCS changes, and other body composition measurements, as well as calf weaning weight. In this study, 24 spring-calving, mature Angus beef cows were classified as either hard-fleshing or easy-fleshing based on BCS and ultrasound measurements for back fat and rump fat. The intake study took place during the second trimester, cows were assigned to an easy- or hard-fleshing pen based on treatment where they remained for the entirety of the 45-day intake study. Each treatment was replicated three times in a completely randomized design. Milk data collection began one month after calving with monthly milkings from May—August. There were no differences (P = 0.9) in DMI, although hard-fleshing cows had greater DMI calculated on a metabolic body weight basis (P = 0.05). There was a trend (P = 0.12) for hard-fleshing cows to wean heavier calves, although there was no difference in mean milk yield (P = 0.44). Body condition score was positively correlated with protein and carbohydrate content of milk with easy-fleshing cows having greater contents of both (P = 0.02 and P < 0.01, respectively). Overall, an increase in BCS without an increase in DMI may be beneficial from a reproductive standpoint, though more research in this area is needed.


Author(s):  
Carole Lafreniere ◽  
Robert Berthiaume ◽  
Leo Giesen ◽  
Cheryl Campbell ◽  
Dale Gardner ◽  
...  

Pregnant beef cows (56; 727 ± 102 kg BW) in second trimester were used to examine black spruce (BSP) needles and branches for replacing alfalfa silage in wintering cow diets. Five dietary treatments assessed BSP inclusion rates (0, 15, 22.5, 30, 37.5% in the diet) for 92 days up until 2 weeks before start of calving using a randomized complete block design (10-12 cows/treatment). There were linear decreases (P < 0.001) in total weight gain, average daily gain (ADG) and dry matter intakes (DMI) as amounts of dietary BSP increased. Low DMI feeding BSP may be attributed to palatability issues and lower rates of digestion. Changes in body condition score (BCS) increased(P < 0.003) as dietary BSP increased. These effects are supported by corresponding linear decreases (P < 0.001) for changes in rump fat cover and increases (P < 0.001) in serum non-esterified fatty acids as dietary BSP increased. Post-feeding of test diets, there were no dietary treatment differences (P > 0.42) for calf birth and weaning weights and cow pregnancy and culling rates. Based on this study, incorporation of BSP into gestating cow diets cannot be recommended.


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