The effects of genotype, age, pregnancy, lactation and rumen characteristics on voluntary intake of roughage diets by cattle

1986 ◽  
Vol 37 (5) ◽  
pp. 549 ◽  
Author(s):  
RA Hunter ◽  
BD Siebert
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Late Pregnancy ◽  
Poor Quality ◽  
Heteropogon Contortus ◽  
Lactating Cows ◽  
Significant Difference ◽  
Pregnancy And Lactation ◽  
Rate Of Decline ◽  
Brahman Steers

The effects of genotype, age and liveweight, pregnancy and lactation on the voluntary feed intake by cattle of roughage diets of different qualities were studied in a number of experiments. The diets ranged from poor quality (low-nitrogen, high-fibre) spear grass (Heteropogon contortus) hay on which intakes were low ( 1 1 g DM/kg liveweight (LW)) to good quality lucerne (Medicago sativa) hay (26 g DM/kg LW). On the poorest-quality diet, differences in intake between Bos taurus and Bos indicus were not significant. However, on the higher quality diets Herefords (Bos taurus) ate significantly (P < 0.05) more than Brahmans (Bos indicus). In addition, as the quality of the diet improved from speargrass through to lucerne, the breed difference in favour of the Herefords became progressively greater and the variability between animals progressively smaller as a proportion of intake. Another study showed that with increasing age and liveweight of steers, intake per unit body weight declined, the rate of decline being significantly (P < 0.05) greater on good-quality lucerne compared to a poor-quality speargrass diet. There was no significant difference between Aberdeen Angus (Bos taurus) and Brahman steers in the rate of decline of intake of each diet with increasing age and liveweight of the steers. Another experiment which measured intake of pregnant and lactating heifers showed that the amount of feed eaten by pregnant heifers increased with increasing liveweight in late pregnancy, with intake per unit liveweight remaining constant. Lactating cows ate 35% more on a liveweight basis than their nonpregnant, non-lactating counterparts. These results are discussed in relation to mechanisms which control intake of roughage diets in ruminants, especially those associated with energy metabolism.

scholarly journals Utilization of low-quality roughage by Bos taurus and Bos indicus cattle

1985 ◽  
Vol 53 (3) ◽  
pp. 637-648 ◽  
Author(s):  
R. A. Hunter ◽  
S. D. Siebert
Keyword(s):  
Cell Wall ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Digestion Rate ◽  
Heteropogon Contortus ◽  
Breed Difference ◽  
Cell Wall Constituent ◽  
Brahman Steers

1. Six Hereford and six Brahman steers were fed ad lib. Pangola grass (Digztaria decumbens) and Spear grass (Heteropogon contortus) hay alone and supplemented with rumen-degradable nitrogen and sulphur and minerals. The rumen digestion of the two feeds was determined by reference to the disappearance of substrate from nylon bags suspended in the rumen and withdrawn after intervals ranging from 8 to 120 h.2. The digestion of the unsupplemented Pangola grass diet occurred more rapidly in Brahmans than in Herefords and was associated with higher rumen ammonia concentrations in Brahmans (40 v. 16 mg/l). The rumen NH3, concentrations were increased to over 100 mg/l by supplementation. The digestion rate increased in both breeds after supplementation and the breed difference disappeared. Increases in digestion rate were not achieved above NH3, concentrations of 60–80 mg/l.3. Spear grass, especially the cell-wall-constituent fraction, was more resistant to digestion than Pangola grass. Digestion of the unsupplemented Spear grass diet proceeded more rapidly in Brahmans than in Herefords. The digestion rate in Brahmans were similar irrespective of whether the diet was supplemented or not. Supplementation increased digestion rate in Herefords.

Milk yield and mammary function in dairy cows milked four times daily

1990 ◽  
Vol 57 (3) ◽  
pp. 285-294 ◽  
Author(s):  
J. Eric Hillerton ◽  
Christopher H. Knight ◽  
Alan Turvey ◽  
Stephen D. Wheatley ◽  
Colin J. Wilde
Keyword(s):  
Milk Yield ◽  
Enzyme Activities ◽  
Milk Protein ◽  
Lactating Cows ◽  
Milk Protein Content ◽  
Significant Difference ◽  
The Mean ◽  
Milking Frequency ◽  
Rate Of Decline

SummaryGroups of lactating cows and heifers were milked four times daily in two diagonally opposed glands for 4 weeks, and the effects on milk yield studied relative to twice-daily milked glands as controls. Mammary enzyme activities, in vitro synthesis rates of milk constituents and histological scoring were determined in mammary biopsy samples obtained at the end of this period. These were used for assessment of mammary function. Frequent milking increased milk yield only in the treated glands, the contralateral control glands continuing to decline in yield at ~ 2%/week. There was no significant difference in response between cows and heifers; the mean increase in yield was 10·4%. The rate of decline in milk yield tended to decrease with frequent milking, to ~ 1%/week. Consequently the yield of the treated glands continued to be elevated above that of the controls for some time after reversion to overall twice daily milking. Milk protein content was increased slightly by frequent milking. Mammary enzyme activities were ~ 18% higher in the treated glands than in the controls. Synthesis rates of lactose, casein and total protein were unaffected by milking frequency, but were all lower in the gland selected for the second biopsy, reflecting the reduction in milk yield caused by the first biopsy. DNA synthesis was increased by milking frequency, as were the size and number of epithelial cells in histological sections.

scholarly journals Utilization of low-quality roughage byBos taurusandBos indicuscattle

1985 ◽  
Vol 53 (3) ◽  
pp. 649-656 ◽  
Author(s):  
R. A. Hunter ◽  
B. D. Siebert
Keyword(s):  
Dry Matter ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Dietary Factors ◽  
Plasma Urea ◽  
Mean Retention Time ◽  
Digitaria Decumbens ◽  
Breed Difference ◽  
Significant Difference ◽  
The Mean

1. In a number of experiments voluntary food intake of three low-quality roughages, either alone or supplemented with rumen-degradable nitrogen and sulphur and minerals, was measured in Brahman (Bos indicus) and Hereford (Bos taurus) steers. The chaffed hays were Spear grass (Heteropogon conform) (6.2 g N/kg organic matter (OM)), Pangola grass (Digitaria decumbens) (7.9 g N/kg OM), and Pangola grass (12.0 g N/kg OM). Rumen characteristics relating to rate of fluid outflow from the rumen were also determined.2. There was no significant difference between breeds in the dry-matter intakes of the unsupplemented diets which ranged from 11.3 to 17.8 g/kg body-weight (BW) by Herefords and from 11.8 to 16.1 g/kg BW by Brahmans.3. Supplementation of Spear grass with N and S significantly (P < 0.05) increased intake by Herefords (24%) but not by Brahmans. When the lower-N Pangola grass was supplemented there was a significant increase in intake by both breeds with the magnitude of the response in Herefords (42%) (P < 0.001) being greater than that in Brahmans (15%) (P < 0.05). The intakes of both the supplemented Spear grass and the lower-N Pangola diets were significantly (P < 0.05) greater by Herefords than Brahmans. There was no breed difference in intake when the higher-N Pangola grass was supplemented. Both breeds recorded an 8% intake response to supplementation, although the increase was only significant (P < 0.05) in Herefords.4. The mean retention time of fluid in the rumen on the unsupplemented Pangola grass diet of lower N content was 12.7 h in Brahmans compared with 17.5 h in Herefords (P < 0.01). When the higher-N Pangola was fed, both alone and supplemented, the mean retention times were similar on both diets (10.5 and 9.9 h for Herefords; 9.5 and 8.1 h for Brahmans for unsupplemented and supplemented diets respectively).5. Plasma urea concentrations were higher in Brahmans than in Herefords on all diets. Rumen ammonia concentrations were significantly (P < 0.001) higher in Brahmans than Herefords when the lower-N Pangola grass diet was unsupplemented.6. The intakes and the variable intake responses to supplementation between breeds and diets are discussed in relation to a number of animal and dietary factors.

Digestion of mature pangola grass (Digitaria decumbens) by Bos taurus and Bos indicus cattle

1986 ◽  
Vol 37 (6) ◽  
pp. 665 ◽  
Author(s):  
RA Hunter ◽  
BD Siebert
Keyword(s):  
Cell Wall ◽  
Crude Protein ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Nitrogen Flow ◽  
Tropical Grasses ◽  
Protein Requirements ◽  
Digitaria Decumbens ◽  
Significant Difference ◽  
Flow Through

The digestion of mature pangola grass (Digitaria decurnbens) by Hereford (Bos taurus) and Brahman (Bos indicus) steers was studied. There was no significant difference between breeds in the digestion of organic matter (OM) and cell wall constituents (CWC). The OM digestibility in the whole tract was 0.59 with 90% of the digestion occurring in the stomachs. There was a significantly (P < 0.05) greater nonammonia nitrogen flow through the abomasum in Herefords (66 g/day) than Brahmans (59 g/day). Likewise the ratio of crude protein digested in the intestines to digestible OM (DCPi:DOMI) was higher (P < 0.05) in Herefords (0.120) than in Brahmans (0.102). In both breeds 66% of the nitrogen associated with the CWC was digested in the whole tract, essentially all digestion occurring in the stomachs. These results for pangola grass, especially the DCPi:DOMI ratios, are compared with the digestion characteristics of other tropical grasses and are discussed in terms of the capacity of tropical grasses to meet the protein requirements of growing cattle.

Corrigendum - Relative efficiency of Merino and Border Leicester × Merino ewes

1978 ◽  
Vol 29 (3) ◽  
pp. 605
Author(s):  
DO Kleemann ◽  
CHS Dolling
Keyword(s):  
Organic Matter ◽  
Late Pregnancy ◽  
Animal Tissue ◽  
Carcass Weight ◽  
Ewe Lambs ◽  
Significant Difference ◽  
Ewe Lamb ◽  
Pregnancy And Lactation ◽  
Ad Libitum ◽  
The Difference

Thirteen South Australian strong-wool Merino ewes and eight Border Leicester × Merino ewes mated to Poll Dorset rams were fed on lucerne pellets ad libitum during late pregnancy and lactation in pens. Each of their single-born progeny was slaughtered at 33 kg full liveweight. Breeds were compared for efficiency of the ewe (organic matter intake per unit liveweight and clean wool per unit intake), efficiency of the lamb (liveweight and body solids gain per litre of milk), and efficiency of the ewe-lamb unit (liveweight and carcass weight per unit intake). Border Leicester × Merino ewes ate 7% less organic matter per unit liveweight than Merino ewes during lactation; however, there was no significant difference during late pregnancy. In terms of absolute intake 120 Merinos = 100 Border Leicester × Merinos. Border Leicester × Merino ewes were 73% as efficient in converting feed to clean wool as Merino ewes. Merino ewes grew wool of smaller diameter and higher crimp frequency than crossbreds. Lambs from the Merino ewes were as efficient in converting milk into animal tissue as the progeny from Border Leicester x Merino ewes during the first 4 weeks of suckling. Lambs from Merino ewes required on average 25 extra days to grow to the same slaughter weight and ate 110% more organic matter from solid feed than lambs from crossbred ewes. However, the proportion of feed eaten by the lamb was small (10%) compared with that eaten by the ewe. Lambs from crossbred ewes were 23% heavier than those from Merino ewes at the same age. The crossbred ewe-lamb unit, however, consumed 20% more feed and hence was as efficient as the Merino ewe–lamb unit. The Merino ewe–lamb unit was more efficient than the crossbred ewe-lamb unit when the lamb genotypes were slaughtered at the same liveweight (P < 0.05); however, the difference was not significant when expressed as carcass weight per unit intake.

PSXII-19 Organ and cellular contributions to heat production in Brahman and Angus steers

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 422-423
Author(s):  
Briana Hawryluk ◽  
Morgan McKinney ◽  
Chloe Gingerich ◽  
Lindsey Bell ◽  
Patricia Ramos ◽  
...  
Keyword(s):  
Metabolic Activity ◽  
Heat Production ◽  
Citrate Synthase ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Cellular Level ◽  
Organ Size ◽  
Heart Weight ◽  
Brahman Steers ◽  
And Shifts

Abstract Reductions in basal metabolism and growth rate appear to contribute to decreased heat production of Bos indicus breeds. Lower metabolic rate may be due to smaller organ size and lower metabolic activity. Liver and heart account for high percentage of metabolic activity relative to their weight, and at a cellular level, mitochondria are responsible for producing energy for cellular maintenance. Our objective was to determine liver and heart weight and evaluate expression of key mitochondrial proteins in Bos indicus (80–100% Brahman) and Bos taurus (80–100% Angus) steers. Steers (n = 14 per breed) were harvested at the university meat laboratory. After evisceration, livers and hearts were weighed, and samples were frozen in liquid nitrogen for further analyses. Western blotting was used to determine expression of proteins in mitochondrial energy production: citrate synthase, a marker of mitochondria content; succinate dehydrogenase B (SDH-B), complex II; cytochrome c oxidase subunit IV, complex IV; and ATP synthase subunit 5A (ATP5A), complex V. Data were analyzed using an unpaired t-test in SAS-JMP. Although steers were similar age at slaughter (P = 0.84), Brahman steers weighed less (P &lt; 0.0001) and thus produced lighter carcasses (P &lt; 0.0001) and smaller livers and hearts (P &lt; 0.0001). On a relative basis (kg organ/kg BW), Brahman tended to possess smaller hearts (P = 0.06) and smaller livers (P = 0.03). Expression of mitochondria proteins in heart did not differ between breeds (P &gt; 0.3). However, Brahman exhibited lower expression of SDH-B (P = 0.005) but tended to have higher expression of ATP5A (P = 0.07) in liver. Altogether, this supports that smaller organ size is a contributing factor to lower heat production in heat-tolerant Brahman steers, and shifts in mitochondria protein expression in liver may impact energy metabolism at the cellular level.

The performance of Brahman-Shorthorn and Sahiwal-Shorthorn beef cattle in the dry tropics of northern Queensland. 3. Birth weights and growth to weaning

1993 ◽  
Vol 33 (2) ◽  
pp. 119 ◽  
Author(s):  
G Fordyce ◽  
TA James ◽  
RG Holroyd ◽  
NJ Beaman ◽  
RJ Mayer ◽  
...  
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Growth Rates ◽  
Bos Taurus ◽  
Growth Traits ◽  
Bos Indicus ◽  
Late Pregnancy ◽  
Growing Season ◽  
Late Generation ◽  
Calving Season

The birth weights and weaning weights of Bos indicus cross calves from 4 inter se mated herd groups in a dry tropical environment were studied. The calving season commenced in late October, about 2 weeks before the start of the pasture-growing season. Second and subsequent generations of 1/2 Brahman and 1/2 Sahiwal crosses and first backcross, and later generations of 3/4 Brahman and 3/4 Sahiwal crosses, were represented. The Bos taurus component of the crosses was primarily Beef Shorthorn. In general, Brahman crosses were heavier at birth and grew faster to weaning than Sahiwal crosses (P<0.05), with consequent advantages in weaning weights of 11 and 6 kg in first backcross and late generation crosses, respectively. There was a birth weight advantage (P<0.05) of 1/2 crosses over 3/4 crosses, which was eroded by the time of weaning. Superior growth rates of 3/4 crosses were primarily expressed in years with greater nutritional stress and appeared to be due to better adaptation to environmental stresses by the calf. The only difference between filial generations was the growth rate advantage (P<0.05) of F2 1/2 crosses over F3 1/2 crosses, apparently due to suckling of F1 and F2 dams, respectively. Males exhibited an 8% average advantage (P<0.05) over females for all weight and growth traits in late generation calves. Calves with mature dams were 1.8 kg heavier (P<0.05) at birth. This, along with their higher (P<0.05) preweaning growth rate (19-49 g/day), resulted in calves with mature dams being 4-10 kg heavier (P<0.05) at weaning than calves of young cows. Differences between years in birth weights and preweaning growth rates were <25% (P<0.05). Birth weight was affected by nutrition of the dam in late pregnancy (early calves were generally about 1 kg lighter than late calves), and growth of calves was higher in years when the pasture growing season commenced earlier.

Genetic and environmental effects on the fertility of beef cattle in a tropical environment.

1989 ◽  
Vol 40 (5) ◽  
pp. 1085 ◽  
Author(s):  
MJ Mackinnon ◽  
DJS Hetzel ◽  
JF Taylor
Keyword(s):  
Y Chromosome ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Phenotypic Selection ◽  
High Grade ◽  
Breeding Lines ◽  
Lactating Cows ◽  
Filial Generation ◽  
Reciprocal Crossing ◽  
Calving Rate

Calving data recorded over a 28-year period were analysed for the effects of breed, filial generation, lactational status, cow liveweight at mating and year of mating. The herd comprised six distinct breeding lines ('breeds') and analysis was performed both within and across breeds. The least fertile breeds were the high grade (314-718) Africander (A) and high grade (718-purebred) Brahman (B) cows which had average calving rates of 56% and 55%, respectively. Crossing these with a Hereford- Shorthorn line, which had an average calving rate of 6O%, resulted in 19% heterosis (in absolute calving percentage units) in the F1 Africander-cross (AX) and 16% heterosis in the F1 Brahman-cross (BX). In subsequent generations, 13% residual heterosis remained in the AX, while in the BX only 1% remained. Reciprocal crossing of the AX and BX lines generated 6% heterosis in the Fl AXBX, and all of this was maintained in subsequent generations. In the F2 et seq. generations of the AXBX, the line of animals carrying the Bos indicus Y chromosome was similarly fertile (P> 0.05) to the line carrying the Bos taurus Y chromosome. Lactating mature (3 5-year-old) cows were on average 15% less fertile than non-lactating cows. This lactation effect was larger in younger cows. There was a curvilinear response in fertility to increasing liveweight at mating which was most pronounced in 2-year-old heifers. Breed appeared to react differently to the effects of environmental stress where the AX and HS cows were limited more by liveweight, and the BX and AXBX were more limited by lactation effects per se. Lactating cows that also lactated in the previous year were 6% more fertile than lactating cows that were dry the previous year, suggesting that calving records are moderately repeatable and therefore that permanent differences in fertility could be established by phenotypic selection.

The performance of Brahman-Shorthorn and Sahiwal-Shorthorn cattle in the dry tropics of northern Queensland. 4. Postweaning growth and carcass traits

1993 ◽  
Vol 33 (5) ◽  
pp. 531 ◽  
Author(s):  
G Fordyce ◽  
ID Loxton ◽  
RG Holroyd ◽  
RJ Mayer
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Meat Processing ◽  
Wet Season ◽  
Average Growth ◽  
Longissimus Dorsi Muscle ◽  
Dry Seasons ◽  
The Difference ◽  
Breed Crosses ◽  
Brahman Steers

Postweaning growth to slaughter at 42 months of age in males and to initial mating at 27 months of age in females was studied in 4 inter se mated Bos indicus crosses in a dry tropical environment. Six-monthly growth periods from weaning (at about 6 months of age) generally coincided with wet and dry seasons. The cattle represented were second and subsequent generations of 112 Brahman and 112 Sahiwal crosses and first backcross and later generations of 314 Brahman and 314 Sahiwal crosses, The Bos taurus component of the crosses was primarily Beef Shorthorn. Annual growth averaged 300 g/day, with annual gain ranging from 60 to 180 kg. Average growth rates were about 50 g/day in the dry season (-352 to +374 g/day) and 500 g/day in the wet season (221-830 g/day). Postweaning growth of Brahman crosses was about 4% higher than Sahiwal crosses, with most of this advantage expressed in wet seasons. Sahiwal crosses were earlier maturing than Brahman crosses. Wet season growth was higher in 314 crosses than in 1/2 crosses, which probably reflected significant environmental stress in this period. Higher growth of 3/4 crosses tended to be maintained during dry seasons. Calves born late in a wet season grew more rapidly in dry seasons than early-born calves, so that liveweight differences which were apparent at weaning were reduced by one-third at 24 months of age. The difference between liveweights of weaners with young dams and those with mature dams was also reduced from 12-18 kg to 5-6 kg by 24 months. Dressing percentages of 3/4 cross steers at slaughter were 0.6 units higher than in half crosses, with no difference between Brahman and Sahiwal crosses. Sarcomere lengths, Warner-Bratzler shear force values, and Instron compression values together showed that M. longissimus dorsi muscle samples from 1/2 Brahman steers were the most tender of the breed crosses studied. Samples from Sahiwal cross and 3/4 Brahman steers appeared most affected by connective tissue toughness. Those from 3/4 Sahiwals appeared most affected by meat processing factors, causing them to be the least tender.

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