Effect of reduced dietary non-phytate phosphorus concentration, with or without calcium reduction, in diets supplemented with phytase for weaned piglets from 28 to 63 days of age

2019 ◽  
Vol 59 (12) ◽  
pp. 2236 ◽  
Author(s):  
A. N. Sélos ◽  
J. L. Donzele ◽  
R. F. M. O. Donzele ◽  
T. R. Castro ◽  
E. F. Cardoso ◽  
...  
Keyword(s):  
Average Daily Gain ◽  
Positive Control ◽  
Metacarpal Bone ◽  
Weaned Piglets ◽  
Phytate Phosphorus ◽  
Bone Ash ◽  
Significant Difference ◽  
Bone Mineralisation ◽  
The Impact ◽  
Daily Gain

The aim of this study was to investigate the impact of reduced dietary non-phytate phosphorus (nPP) or nPP and calcium (Ca) concentrations in diets supplemented with phytase on performance, bone mineralisation and serum parameters of weaned piglets from 28 to 63 days of age. A total of 168 barrows and gilts, weaned at 28 days of age, with an average initial bodyweight of 8.11 ± 0.61 kg were randomly allocated in a completely randomised block design. Treatments consisted of a positive control and an additional six treatments, in a 3 × 2 factorial arrangement, totalling seven treatments (Trt). The positive control (PC) diet was formulated to meet or exceed the nutrient requirements of pigs weighing 8–30 kg bodyweight, without phytase supplementation, and the six other diets were formulated similar to the PC, except with a reduction in the nPP concentration of 0.065, 0.130 or 0.195% (Phase Feeding 1 (PF1), PF2 or PF3 respectively) or similar to PF1, PF2 and PF3 minus 0.16% Ca, supplemented with 2000 FTU/kg of phytase, with eight replicate pens/Trt of three piglets each, in a three-phase feeding program. From Day 28 to Day 35, the average daily gain was higher (P < 0.05) and the feed conversion rate was lower (P < 0.05) respectively for piglets fed the PC when compared with those fed PF3 and PC treatment minus 0.160% calcium and minus 0.195% nPP (PF6). In contrast, when evaluating the period from Day 28 to 49, piglets fed PC presented the highest average daily gain, but only differed (P < 0.05) to those fed PF3 and PF6. When considering the overall period, at 63 days of age, no significant difference was detected (P > 0.05) between the PF Trts tested and the PC regarding performance. As for bone mineralisation at 63 days, bone P (BP) decreased as nPP in the diet decreased, regardless of the Ca level. However, except for PF3 and PF6, BP and third metacarpal bone ash concentration were respectively higher for pigs fed the PF Trts, when compared with PC. All treatments containing phytase resulted in a lower bone Ca:BP ratio when compared with PC. Serum P concentrations decreased as nPP in the diet decreased, regardless of the level of dietary Ca. However, with the exception of PF3 and PF6, serum P was not significantly different than pigs fed the PC. In conclusion, reducing nPP or nPP and Ca in diets containing 2000 FTU Ronozyme® HiPhos/kg phytase had no adverse effects on growth performance and increased BP and third metacarpal bone ash concentration compared with pigs fed a nutritionally adequate control diet.

scholarly journals PSIV-20 Impact of OutPace® Feed Additive on nursery pig growth performance: A meta-analysis

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 175-176
Author(s):  
Benjamin Bass ◽  
Stacie Crowder ◽  
Terry Weeden ◽  
Murali Raghavendra Rao ◽  
Brenda de Rodas ◽  
...  
Keyword(s):  
Feed Intake ◽  
Feed Efficiency ◽  
Meta Analysis ◽  
Block Design ◽  
Phase 1 ◽  
Average Daily Gain ◽  
Feed Additive ◽  
Significant Difference ◽  
The Impact ◽  
Daily Gain

Abstract OutPace® Feed Additive (OP), contains a carefully researched blend of activated medium chain fatty acids (MCFAs; PMI, Arden Hills, MN), formulated to help mitigate the effects of stress in nursery pigs. Several studies using OP in both late and full nursery periods resulted in improved pig performance. A meta-analysis using 9 studies (4 studies during late nursery [15 to 26.8 kg BW] and 5 studies during the full nursery [5.9 to 25.4 kg]) was done to determine the impact of OP (included at 0.25% Phase 1 and 2; 0.125% Phase 3) on average daily gain, average daily feed intake, and feed conversion. The combined data was considered a randomized complete block design. Analysis of variance was completed with mixed models using the GLIMMIX procedure of SAS (SAS 9.4, SAS Institute Inc., Cary, NC) and least squares means were compared using Fisher’s least significant difference (P < 0.05). In the analysis of 5 studies conducted in late nursery (45 pens/treatment of 6 to 20 pigs/pen), pigs provided OP had higher average daily gain (0.67 vs 0.63 kg/d; P < 0.05), increased average daily feed intake (0.99 vs 0.97 kg/d; P < 0.05), and improved feed efficiency (0.67 vs 0.65 kg gain/kg feed intake; P < 0.05) compared to pigs fed control diets. Additionally, when pigs were provided OP throughout the nursery period (20 pens/treatment of 7 to 20 pigs/pen), average daily gain was increased 6.1% (0.48 vs 0.45 kg/d; P < 0.05), average daily feed intake tended to be increased 2.2% (0.62 vs 0.61 kg/d; P < 0.1), and feed efficiency was improved 2.7% (0.76 vs 0.74 kg gain/kg feed intake; P < 0.05) compared to pigs provided control diets. In conclusion, providing OP to pigs during the nursery period improved ADG and feed efficiency.

scholarly journals Porcine ear necrosis in weaned piglets: prevalence and impact on daily weight gain

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mateusz Malik ◽  
Alexandra Schoos ◽  
Ilias Chantziaras ◽  
Dries Donkers ◽  
Siska Croubels ◽  
...  
Keyword(s):  
Average Daily Gain ◽  
Control Measures ◽  
Daily Weight Gain ◽  
Weaned Piglets ◽  
Nursery Pigs ◽  
Low Concentrations ◽  
Pig Farm ◽  
The Impact ◽  
Daily Gain ◽  
Black Discoloration

Abstract Background Porcine ear necrosis (PEN) in pigs is characterized by a blue to black discoloration of the tip or margin of the ear followed by necrosis. The present study investigated the prevalence of PEN in a Belgian pig farm with PEN problems in nursery pigs, the effect of a mycotoxin detoxifier added to the feed on PEN prevalence, and the impact of PEN on the piglets’ growth. Six consecutive batches of weaned piglets [565–751 piglets per batch, (n = 3898)] were included. For each weaning batch, the presence and severity of PEN during the nursery period (3–10 weeks of age) were recorded weekly. Average daily gain (ADG) was calculated by weighing 597 individual piglets divided over the six batches. Additionally different mycotoxins were measured in the feed using LC–MS/MS analysis, and to three randomly selected batches, a mycotoxin detoxifier (Mycofix® Plus 5E, Biomin) was added to the feed. Results At the end of the nursery period, 11.0–32.0% of the piglets in each batch were affected. The prevalence increased with the number of weeks post-weaning, especially from week 4 after weaning onwards. Mild, moderate, severe and very severe lesions represented 84.6%, 14.0%, 1.3% and 0.1% of all lesions, respectively. Different mycotoxins were present in the feed, but all at low concentrations. The mean ADG (± SD) for pigs without (n = 243) and with (n = 158) lesions was 391 g (± 71 g) and 394 g (± 65 g), respectively (P > 0.05). The ADG for mildly affected (387 g ± 68 g) and moderately affected piglets (420 g ± 44 g) was not significantly different (P > 0.05). The PEN prevalence in the batches without or with the mycotoxin detoxifier was 25% and 22%, respectively (P > 0.05). Conclusions Twenty-three percent of animals showed lesions at the end of the nursery. Affected pigs did not have a lower ADG compared to non-affected animals, which might be explained by the fact that most affected piglets only had mild lesions. The addition of a mycotoxin detoxifier did not influence the prevalence of PEN, possibly because of the low levels of mycotoxin contamination. Further research is warranted to assess the impact of more severe PEN lesions and the effect of control measures.

Dietary calcium requirements of Sheldrake ducklings from 1 to 21 days of age

2019 ◽  
Vol 59 (5) ◽  
pp. 887 ◽  
Author(s):  
Y. W. Zhu ◽  
X. X. Jiang ◽  
J. Wen ◽  
W. C. Wang ◽  
L. Yang
Keyword(s):  
Average Daily Gain ◽  
Basal Diet ◽  
Dietary Calcium ◽  
Regression Analyses ◽  
Mineral Density ◽  
Phytate Phosphorus ◽  
Maximal Weight ◽  
Bone Mineralisation ◽  
Tibia Ash ◽  
Daily Gain

An experiment was conducted to investigate the effect of dietary calcium (Ca) level on growth performance and bone characteristics to evaluate the Ca requirements for Sheldrake ducklings from 1 to 21 days of age. A total of 1080 day-old male Campbell Sheldrake ducklings were randomly allotted to one of six treatments with six replicate cages of 30 birds per cage with a completely randomised design. A basal diet with 0.40% non-phytate phosphorus was supplemented with Ca source (calcium carbonate) to achieve graded concentrations of Ca (0.45–1.20%) in diets with an increment of 0.15%. The bodyweight, average daily gain and average daily feed intake displayed quadratic responses to increasing concentrations of dietary Ca with maximal responses for ducklings fed the diets with 0.60 and 0.75% Ca. Serum Ca concentration, tibia ash percentage, Ca content in tibia ash and bone mineral density were increased linearly (P < 0.02) as dietary Ca concentrations increased. According to the non-linear regression analyses, the Ca requirements for maximal weight gain and bone mineralisation of Sheldrake ducklings from 1 to 21 days of age were estimated at 0.60% and 0.64–0.87% respectively.

scholarly journals Grid search approach to discriminate between old and recent inbreeding using phenotypic, pedigree and genomic information

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Pattarapol Sumreddee ◽  
El Hamidi Hay ◽  
Sajjad Toghiani ◽  
Andrew Roberts ◽  
Samuel E. Aggrey ◽  
...  
Keyword(s):  
Common Ancestor ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Recent Common Ancestor ◽  
Pedigree Information ◽  
Grid Search ◽  
Genomic Information ◽  
The Impact ◽  
Daily Gain ◽  
Harmful Effects

Abstract Background Although inbreeding caused by the mating of animals related through a recent common ancestor is expected to have more harmful effects on phenotypes than ancient inbreeding (old inbreeding), estimating these effects requires a clear definition of recent (new) and ancient (old) inbreeding. Several methods have been proposed to classify inbreeding using pedigree and genomic data. Unfortunately, these methods are largely based on heuristic criteria such as the number of generations from a common ancestor or length of runs of homozygosity (ROH) segments. To mitigate these deficiencies, this study aimed to develop a method to classify pedigree and genomic inbreeding into recent and ancient classes based on a grid search algorithm driven by the assumption that new inbreeding tends to have a more pronounced detrimental effect on traits. The proposed method was tested using a cattle population characterized by a deep pedigree. Results Effects of recent and ancient inbreeding were assessed on four growth traits (birth, weaning and yearling weights and average daily gain). Thresholds to classify inbreeding into recent and ancient classes were trait-specific and varied across traits and sources of information. Using pedigree information, inbreeding generated in the last 10 to 11 generations was considered as recent. When genomic information (ROH) was used, thresholds ranged between four to seven generations, indicating, in part, the ability of ROH segments to characterize the harmful effects of inbreeding in shorter periods of time. Nevertheless, using the proposed classification method, the discrimination between new and old inbreeding was less robust when ROH segments were used compared to pedigree. Using several model comparison criteria, the proposed approach was generally better than existing methods. Recent inbreeding appeared to be more harmful across the growth traits analyzed. However, both new and old inbreeding were found to be associated with decreased yearling weight and average daily gain. Conclusions The proposed method provided a more objective quantitative approach for the classification of inbreeding. The proposed method detected a clear divergence in the effects of old and recent inbreeding using pedigree data and it was superior to existing methods for all analyzed traits. Using ROH data, the discrimination between old and recent inbreeding was less clear and the proposed method was superior to existing approaches for two out of the four analyzed traits. Deleterious effects of recent inbreeding were detected sooner (fewer generations) using genomic information than pedigree. Difference in the results using genomic and pedigree information could be due to the dissimilarity in the number of generations to a common ancestor. Additionally, the uncertainty associated with the identification of ROH segments and associated inbreeding could have an effect on the results. Potential biases in the estimation of inbreeding effects may occur when new and old inbreeding are discriminated based on arbitrary thresholds. To minimize the impact of inbreeding, mating designs should take the different inbreeding origins into consideration.

scholarly journals PSIII-5 Effects of ingredient composition of oral drenches in small piglets post-farrowing on average daily gain and pre-wean mortality

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 238-238
Author(s):  
Olivia Harrison ◽  
Samantha Tauer ◽  
Brent Frederick
Keyword(s):  
Birth Weight ◽  
Average Daily Gain ◽  
High Energy ◽  
Experimental Unit ◽  
Swine Industry ◽  
Bioactive Proteins ◽  
Randomized Design ◽  
Significant Difference ◽  
Key Factor ◽  
Daily Gain

Abstract Number of pigs born alive has been a key factor of the increasing efficiency of the U.S. swine industry. However, with increased pigs in the uterus, birth weight has been negatively impacted, with more small or at-risk pigs being born per litter. In order to overcome these changes, a study testing three commercial oral drenches against a control to determine which would increase average daily gain and decrease preweaning mortality. In a completely randomized design, 877 one-day-old suckling pigs from a high-health farm were selected for the experiment if they appeared to be in the bottom 20% of bodyweight compared to their contemporaries. Selected pigs were given one of four drenching treatments: 1) none (control), 2) bioactive proteins (BP), 3) high energy sugars (HES), and 4) immunoglobulins (IgY). Pigs were weighed on d 1 and d 19 of age (weaning), with mortality tracked during the suckling period. Data were analyzed using SAS v 9.4 (Cary, NC), with pig as the experimental unit and an accepted alpha of 0.05. Treatment had no detected effect on birth weight, weaning weight, ADG, or mortality (P = 0.79, 0.96, 0.86, 0.38 respectively). Likewise, statistical contrasts were used to determine there was no detected impact (P > 0.10) of drench, regardless of type, compared to the control in any measured response criteria. Interesting, pigs drenched with BP or IgY had numerically lower preweaning mortality (11.2 and 11.5% respectively), than those administered the control or HES (15.4 and 15.2%, respectively). In conclusion, this experiment showed no significant difference in the performance between piglets given no product vs. those drenched with bioactive proteins, high energy sugars, or immunoglobulins. However, additional research is warranted with greater replication or disease stressors to better understand if oral drenches may improve preweaning performance or mortality in different situations.

scholarly journals Effect of Zinc Source and Level on Growth Performance and Zinc Status of Weaned Piglets

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2030
Author(s):  
Anna Szuba-Trznadel ◽  
Anna Rząsa ◽  
Tomasz Hikawczuk ◽  
Bogusław Fuchs
Keyword(s):  
Zinc Oxide ◽  
Growth Performance ◽  
Average Daily Gain ◽  
Environmental Damage ◽  
Weaned Piglets ◽  
Group Iii ◽  
Group I ◽  
Therapeutic Doses ◽  
Daily Gain ◽  
Excessive Accumulation

The aim of this study was to evaluate the effect of zinc (Zn) supplementation in different commercial forms on the growth performance, health status, and Zn balance of weaners in field conditions. The animals were fed pre-starter (from the 28th to 47th day of life) and starter (from the 48th to 74th day of life) mixtures differing in Zn form and concentration. Group I was given ZnSO4 at 150 mg kg−1; Group II received pre-starter zinc oxide (ZnO) at 3000 mg kg−1 and starter at 150 mg kg−1; and Group III was given 150 mg kg−1 of zinc oxide nanoparticles (nZnO). We found that the average daily gain in Group I was significantly lower, compared to Groups II and III. A commonly accepted level of Zn (150 mg kg−1) as nZnO can be recommended, instead of therapeutic doses of Zn preparations with the same efficiency. Moreover, a lower level of Zn in the diet can prevent the excessive accumulation of this element in waste and, thus, reduce environmental damage.

scholarly journals THE EFFECTS OF LEVELS OF ISOLATION, OR VARIETAL DIFFERENCES IN, HIGH FIBRE HULL FRACTION OF LOW GLUCOSINOLATE RAPESEED MEALS ON RAT OR PIG PERFORMANCE

1978 ◽  
Vol 58 (4) ◽  
pp. 743-752 ◽  
Author(s):  
J. J. KENNELLY ◽  
F. X. AHERNE ◽  
A. J. LEWIS
Keyword(s):  
Feed Intake ◽  
Average Daily Gain ◽  
Rapeseed Meal ◽  
Sprague Dawley ◽  
Crude Fibre ◽  
Gain Ratio ◽  
Sprague Dawley Rats ◽  
Significant Difference ◽  
Pig Performance ◽  
Daily Gain

Forty-eight crossbred pigs of average initial weight 21 kg were fed 10% Tower rapeseed meal (RSM) and 10% Candle RSM as partial replacements for soybean meal (SBM). Diets were formulated to be isocaloric. Pigs fed the SBM diet consumed less feed, gained significantly (P < 0.01) faster and were more efficient at converting feed to gain than those fed the RSM diets. Performance of pigs fed Candle RSM was not significantly different to that obtained with Tower RSM. In a second experiment, dehulled Tower RSM and Tower RSM hulls were mixed in amounts to produce RSM with crude fibre levels of 6.8, 10.8, 13.5 and 15.8%. The simulated RSM and Tower and Candle RSM were used to completely replace SBM in the diets of weanling (75 g) Sprague-Dawley rats. Rats fed SBM had significantly (P < 0.05) higher average daily gain (ADG) than those fed Tower or Candle RSM, or diets containing the rapeseed meats. There was no significant (P < 0.05) difference in ADG, feed intake or feed to gain ratio of rats fed either Tower or Candle RSM. Feed intake, feed to gain ratio and fecal volatile fatty acid concentrations increased while average daily gain decreased with increasing level of hulls in simulated RSM diets. There was no significant difference (P < 0.05) in thyroid weight between rats fed SBM, Tower RSM or Candle RSM.

scholarly journals The Impact of Selection using Residual Average Daily Gain and Marbling EPDs on Growth Performance and Carcass Traits in Angus Steers

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
T. R. Krause ◽  
E. R. Moore ◽  
J. Duggin ◽  
J. R. Segers ◽  
T. D. Pringle
Keyword(s):  
Growth Performance ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Backfat Thickness ◽  
Feeding Trial ◽  
Body Weights ◽  
Selection For ◽  
Carcass Merit ◽  
The Impact ◽  
Daily Gain

ObjectivesProfitability in the beef industry has narrow margins regulated by revenue from output traits like growth and carcass merit, but profitability is also largely impacted by input expenses like feed costs. Selecting for improvements in feed efficiency during the finishing phase, one of the most feed intensive segments of the industry, can help to mitigate those input costs. This study compared growth performance, feed efficiency, body composition, and carcass characteristics in Angus steers (n = 321) from bulls divergently selected for feed efficiency and marbling.Materials and MethodsAngus sires were selected based on high (10th percentile or better) and low (85th percentile or worse) residual average daily gain (RADG) EPD as well as high (fifth percentile or better) and average (near 50th percentile) marbling (MARB) EPD. These criteria resulted in a 2 × 2 factorial design with four breeding lines: high RADG/high MARB, high RADG/average MARB, low RADG/high MARB, low RADG/average MARB. Data were analyzed using MIXED procedures of SAS with RADG and MARB as main effects. Significance was set at α = 0.05. Generation was also analyzed, where generation one (GEN1) steers were from a selected sire while generation two (GEN2) steers were from a selected sire and a selected dam.ResultsUltrasound and carcass data revealed no differences (P ≥ 0.12) in 12th rib backfat thickness from weaning through slaughter for the RADG EPD groups. Yield grade and dressing percent did not differ (P ≥ 0.56) across RADG or MARB groups. At the beginning and end of the feeding trial, the high RADG (P ≤ 0.02) group had larger ultrasound ribeye area (REA) than the low RADG group. Carcass REA tended (P = 0.08) to be larger in the high versus low RADG steers. During the feedlot trial and through slaughter, body weight was heavier (P ≤ 0.006) for the high versus low RADG steers but did not differ (P ≥ 0.44) across MARB EPD. Feed efficiency measures did not differ (P ≥ 0.32) across RADG or MARB groups apart from the tendency (P = 0.08) for residual feed intake to be lower in the high versus low RADG steers. Marbling scores differed (P ≤ 0.04) across RADG and MARB groups with the low RADG steers and the high MARB steers having improved marbling. The quality grade distribution across MARB EPD revealed that the average MARB steers graded 73% Choice and 25% Prime while the high MARB steers graded 56% and 42%, respectively. Slice shear force did not differ (P ≥ 0.32) across RADG or MARB EPD. Body weights tended (P = 0.06) to be heavier at the start of the feeding trial for GEN1 versus GEN2 steers. Total gain, average daily gain, and feed to gain (F:G) differed by generation (P ≤ 0.007) with increased rates of gain and reduced F:G in the GEN2 versus GEN1 steers. Body weights did not differ (P = 0.72) across GEN at the end of the feeding trial. Backfat thickness at the start and end of the feedlot phase was less (P ≤ 0.03) and marbling score was improved (P = 0.02) in the GEN2 versus GEN1 steers, respectively.ConclusionThese results suggest that selection using RADG EPD has negligible impacts on meat quality; and that progress in selection for efficiency can be achieved while advancing carcass quality and value. Furthermore, continued divergent selection for feed efficiency and marbling has the potential to improve feed efficiency through advancements in the rate of gain, while enhancing carcass merit through marbling.

scholarly journals Productive performance of finishing lambs fed with faveleira fodder salt (Cnidoscolus quercifolius Pohl)

2016 ◽  
Vol 37 (2) ◽  
pp. 977
Author(s):  
João Vinícius Barbosa Roberto ◽  
Bonifácio Benicio de Souza ◽  
Gabriel Jorge Carneiro de Oliveira  ◽  
Jaime Miguel de Araujo Filho ◽  
Thaiz Lamy Alves Ribeiro ◽  
...  
Keyword(s):  
Feed Efficiency ◽  
Dry Matter ◽  
Salt Intake ◽  
Average Daily Gain ◽  
Daily Intake ◽  
Mineral Salt ◽  
Productive Performance ◽  
Feed Conversion ◽  
Significant Difference ◽  
Daily Gain

This study evaluated food intake and productive performance of crossbred (½ Santa Inês x ½ dorper) lambs supplemented with different levels of faveleira (Cnidoscolus quercifolius Pohl) fodder salt. Thirty male sheep fed tifton grass hay, water, and faveleira fodder salt were randomly allocated into five treatments with six replicates each. The treatments consisted of diets with different inclusion levels of faveleira hay in the fodder salt composition: Treatment 1 (1% mineral salt + 99% faveleira hay), Treatment 2 (3% mineral salt + 97% faveleira hay), Treatment 3 (5% mineral salt + 95% faveleira hay), Treatment 4 (7% mineral salt + 93% faveleira hay), and Treatment 5 (Control - 100% mineral salt). Intake of dry matter, tifton hay and water, average daily gain, feed conversion, and feed efficiency were not affected by fodder salt supplementation (P > 0.05). There was a significant difference (P < 0.05) in fodder salt intake between Treatments 4 and 5, and daily intake was higher in animals submitted to Treatment 4 (61.0 g day-1). Mineral salt intake increased significantly with increasing mineral salt levels in the diet. However, no significant difference was observed in average daily gain across treatments, indicating that faveleira hay, even in small quantities, and tifton hay were able to meet the nutritional requirements of animals to support a good average daily gain. The inclusion of up to 99% faveleira hay in fodder salt formulations did not affect voluntary intake of forage, water and dry matter, average daily gain, feed conversion, and feed efficiency. Lambs supplemented with faveleira fodder salt had average daily gains within the optimal range for slaughter and high feed conversion and feed efficiency values. Faveleira was shown to be an effective supplementary feed alternative in sheep.

Genetic improvement of meat sheep. 1. A comparison of different methods of correcting weaning weight for age of lamb

1976 ◽  
Vol 16 (80) ◽  
pp. 325 ◽  
Author(s):  
IP Gregory ◽  
EM Roberts ◽  
JW James
Keyword(s):  
Birth Weight ◽  
Genetic Improvement ◽  
Average Daily Gain ◽  
Weaning Weight ◽  
Significant Difference ◽  
Meat Sheep ◽  
Daily Gain ◽  
Weight For Age

Several methods of correcting lamb weaning weight for age were compared. Lambs were weighed at birth, at 90 � 1 day of age, when the oldest and when the youngest lamb was 90 days and when the average age of lambs was 90 days. Weights were adjusted to 90 days by the methods of regression, regression pooled within sire groups, average daily gain with and without a standard birth weight and weight per day of age. All the correction methods examined gave similar results and there was no significant difference between methods. The correlations between the actual 90-day weight and the adjusted weights ranged from 0.922 to 0.960 and were highest when the weights taken when the average age of lambs was 90 days were used as the basis for adjustment. All adjusted weights were significantly biased as estimates of actual 90-day weight, but the bias was least for weights when average age was 90 days.

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