scholarly journals Renewed selection for heat loss in mice: Direct responses and correlated responses in feed intake, body weight, litter size, and conception rate1

2007 ◽  
Vol 85 (3) ◽  
pp. 658-666 ◽  
Author(s):  
J. M. McDonald ◽  
M. K. Nielsen
Keyword(s):  
Body Weight ◽  
Heat Loss ◽  
Litter Size ◽  
Feed Intake ◽  
Correlated Responses ◽  
Selection For

Selection for litter size, body weight, and pelt quality in mink (Mustela vison): correlated responses

1994 ◽  
Vol 72 (5) ◽  
pp. 1126-1137 ◽  
Author(s):  
Gabrielle Lagerkvist ◽  
K. Johansson ◽  
N. Lundeheim
Keyword(s):  
Body Weight ◽  
Litter Size ◽  
Mustela Vison ◽  
Correlated Responses ◽  
Selection For

scholarly journals EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON CORRELATED RESPONSES TO SELECTION FOR POSTWEANING GAIN IN MICE

Genetics ◽  
1973 ◽  
Vol 74 (1) ◽  
pp. 157-170
Author(s):  
E J Eisen ◽  
J P Hanrahan ◽  
J E Legates
Keyword(s):  
Body Weight ◽  
Population Size ◽  
Effective Population Size ◽  
Litter Size ◽  
The Body ◽  
Selection Intensity ◽  
Correlated Responses ◽  
Effective Population ◽  
Population Sizes ◽  
Selection For

ABSTRACT Correlated responses to selection for postweaning gain in mice were studied to determine the influence of population size and selection intensity. Correlated traits measured were three-, six- and eight-week body weights, litter size, twelve-day litter weight, proportion infertile matings and two indexes of reproductive performance. In general, the results agreed with observations made on direct response: correlated responses in the body weight traits and litter size increased as (1) selection intensity increased and (2) effective population size increased. Correlated responses in the body weight traits and litter size were positive in the large population size lines (16 pairs), as expected from the positive genetic correlation between these traits and postweaning gain. However, several negative correlated responses were observed at small population sizes (one and two pairs). Within each level of selection intensity, traits generally associated with fitness tended to decline most in the very small populations (one and two pairs) and in the large populations (16 pairs) for apparently different reasons. The fitness decline at the small effective population sizes was attributable to inbreeding depression. In contrast, it was postulated that the fitness decline at the large effective population size was due to selection moving the population mean for body weight and a trait positively correlated genetically with body weight (i.e., percent body fat) away from an optimum

scholarly journals 269 Effects of high phytase supplementation in lactation diets on sow and litter performance

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 101-102
Author(s):  
Kelsey L Batson ◽  
Hilda I Calderon Cartagena ◽  
Robert D Goodband ◽  
Jason C Woodworth ◽  
Mike D Tokach ◽  
...  
Keyword(s):  
Body Weight ◽  
Litter Size ◽  
Feed Intake ◽  
Control Diet ◽  
Small Scale ◽  
Body Weight Change ◽  
Weaning Weight ◽  
Commercial Trial ◽  
Quadratic Response ◽  
Dietary Treatments

Abstract A total of 109 sows (Line 241; DNA, Columbus, NE) were used in a study to evaluate the effect of increasing phytase concentration in lactation diets on sow and litter performance. On d 107 of gestation, sows were blocked by body weight and parity and allotted to 1 of 3 dietary treatments of increasing phytase concentration (0, 1,000, or 3,000 FYT/kg; Ronozyme HiPhos 2700; DSM Nutritional Products, Inc., Parsippany, NJ). The control diet contained no phytase and was formulated to contain 0.50% standardized total tract digestible phosphorus (STTD P; 0.45% available P) and 0.62% STTD calcium (0.90% total Ca). The same STTD P and Ca concentrations were formulated for the phytase diets considering a release of 0.132 STTD P and 0.094 STTD Ca in both diets. Diets were fed from d 107 of gestation until weaning (d 18 ± 2). Litters were cross-fostered within treatment until 48 h post-farrowing to equalize litter size. Linear and quadratic response to phytase concentration was evaluated using the lmer function in R. There was no evidence for difference in sow body weight change, farrowing performance, wean-to-estrus interval, or litter size among dietary treatments. Sow average daily feed intake from farrowing to weaning tended to increase (linear, P=0.093) as phytase increased. Although not significant (linear, P =0.226), farrowing duration decreased as phytase increased. Litter weaning weight increased (quadratic, P=0.039) and overall litter gain increased (quadratic, P=0.047) with 1,000 FYT of phytase. In summary, sow feed intake tended to increase linearly with increasing phytase; however, feeding 1,000 FYT/kg maximized overall litter gain and weaning weight. This small-scale study suggests sow and litter performance benefits due to high inclusions of dietary phytase; however, a commercial trial with more sows is warranted to confirm these results.

scholarly journals PSVIII-38 Late-Breaking Abstract: Estimating genetic parameters of feed efficiency traits in American mink

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 347-347
Author(s):  
Pourya Davoudi ◽  
Duy Ngoc Do ◽  
Guoyu Hu ◽  
Siavash Salek Ardestani ◽  
Younes Miar
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
American Mink ◽  
Genetic Correlations ◽  
Final Body Weight ◽  
Selection For

Abstract Feed cost is the major input cost in the mink industry and thus improvement of feed efficiency through selection for high feed efficient mink is necessary for the mink farmers. The objective of this study was to estimate the heritability, phenotypic and genetic correlations for different feed efficiency measures, including final body weight (FBW), daily feed intake (DFI), average daily gain (ADG), feed conversion ratio (FCR) and residual feed intake (RFI). For this purpose, 1,088 American mink from the Canadian Center for Fur Animal Research at Dalhousie Faculty of Agriculture were recorded for daily feed intake and body weight from August 1 to November 14 in 2018 and 2019. The univariate models were used to test the significance of sex, birth year and color as fixed effects, and dam as a random effect. Genetic parameters were estimated via bivariate models using ASReml-R version 4. Estimates of heritabilities (±SE) were 0.41±0.10, 0.37±0.11, 0.33±0.14, 0.24±0.09 and 0.22±0.09 for FBW, DFI, ADG, FCR and RFI, respectively. The genetic correlation (±SE) was moderate to high between FCR and RFI (0.68±0.15) and between FCR and ADG (-0.86±0.06). In addition, RFI had low non-significant (P > 0.05) genetic correlations with ADG (0.04 ± 0.26) and BW (0.16 ± 0.24) but significant (P < 0.05) high genetic correlation with DFI (0.74 ± 0.11) indicating that selection for lower RFI will reduce feed intake without adverse effects on the animal size and growth rate. The results suggested that RFI can be implemented in genetic/genomic selection programs to reduce feed intake in the mink production system.

Comparative performance of Omani goats and sheep

1996 ◽  
Vol 127 (1) ◽  
pp. 117-121 ◽  
Author(s):  
F. M. S. Al-Nakib ◽  
E. S. S. Al-Shukaily ◽  
S. S. S. Al-Hanai ◽  
S. A. M. Al-Nabhani
Keyword(s):  
Body Weight ◽  
Litter Size ◽  
Performance Test ◽  
Comparative Performance ◽  
Rhodes Grass ◽  
Sheep Industry ◽  
Body Weights ◽  
Selection For ◽  
Performance Trial

SUMMARYAs part of a long-term breeding programme aimed at improving the performance of Omani goats and sheep, a 3-year performance trial was carried out between 1991 and 1993 to evaluate the reproductive and productive performance of three breeds of goat: Batinah (BT), Dhofari (DH) and Jabal Akhdar (JA), and one breed of local Omani sheep. In each year, flushing started on 1 September, mating started on 1 October and terminated on 15 November, and the kidding/lambing season started on average on 1 March. Kids and lambs were weaned at c. 3 months of age, then put on a 3-month performance test, fed on concentrates ad libitum and Rhodes grass hay. Some 3706 dam and 3011 progeny performance records were available over a 3-year period from 1991 to 1993. Ewes were lighter in body weight and lower in litter size weaned but higher in fertility than the does. Although the lambs had lighter birth weights, they were heavier at weaning and at 6 months of age. Among the goats, the DH does had lighter body weight but higher litter size weaned than both the BT and the JA goats. DH kids were somewhat lighter at birth, weaning and 6-month body weights than the other two breeds but had higher survival.The sheep had higher output per ewe exposed (3·28 kg, 33%) and per ewe lambed (3·27 kg, 26%) and were 35% more efficient in production than the goats. Although the DH goats had a lower output per doe exposed than the BT and JA goats (0·9 kg, 9 % and 0·76 kg, 7% respectively) and per doe kidded (1·11 kg, 9% and 1·29 kg, 10%), they had higher efficiency of production than both BT (0·05 units, 6%) and JA (0·11 units, 14%).In view of these results, attention should be paid to the sheep industry through the introduction of promotion schemes. The DH goats would be even more useful if involved in a crossbreeding scheme and the JA goats would benefit from selection for maternal care.

Response to selection in Australian Merino sheep. III. Single character selection for high and low values of wool weight and its components

1970 ◽  
Vol 21 (6) ◽  
pp. 955 ◽  
Author(s):  
HN Turner ◽  
MG Brooker ◽  
CHS Dolling
Keyword(s):  
Body Weight ◽  
Unit Area ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Initial Response ◽  
Skin Area ◽  
Correlated Responses ◽  
Fibre Number ◽  
Selection For ◽  
Staple Length

Direct and correlated responses are reported for 10 traits in eight pairs of lines under selection for high and low values of single characteristics : clean wool weight per head, clean wool weight per unit skin area (measured only in the groups under selection for it), body weight, wrinkle score, fibre number per unit skin area (adjusted for body weight), fibre diameter, staple length, and percentage clean yield. All groups showed overall divergence in the character under selection, though response was not always symmetrical, and in two cases (long staple and low fibre number) there was no continuing response after the initial response to extreme selection of the base parents. In all except one case, whenever previous estimates of genetic correlation were at the level of 0.2 or higher, correlated responses were in the predicted direction, though not always symmetrical in magnitude. The exception was a previously reported negative correlation between fibre number and staple length, which was not exhibited under selection for either character. Where two characters of a pair were under selection, reciprocal responses agreed in sign; magnitude will be examined in a later paper. Wool per unit area was shown to have a greater influence on clean wool weight than that of surface area, with staple length on this occasion being the most important component of wool per unit area. Reasons for an apparent decrease in the relative importance of fibre number are discussed. Three other points of importance in sheep breeding are again emphasized by these results : 1. Crimp in several pairs of groups was a poor indicator of fibre diameter. 2. Increases in clean wool weight were associated with falls in crimp number, even though fibre diameter actually became finer; diameter, not crimp, should therefore be used as a guide to wool quality. 3. The absence of genetic correlations DL and NL indicates that selection can be for high N (fibre number) with high L (staple length) and low D (fibre diameter) -in other words, a desirable fleece -with no impeding genetic correlations.

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