摘要:

A total of 13 979 Norwegian trotters were born in Norway and registered in the Norwegian Trotting Association between 1972 and 1987. The generation intervals between sire and son(n= 333) and sire and daughter(n= 4366) were 11.23 and 10.91 years, respectively. The corresponding generation intervals between dam and son and dam and daughter were 11.71 and 11.12 years. The average mating age of stallions and mares were 9.81 and 9.91 years. Since 1972, the generation intervals between sire and son and sire and daughter increased significantly. Also, the average age of stallions and mares increased in this period. On average, the stallions and mares first reproduced at 4.69 and 6.24 years of age. Mean reproductive life was 6.40 years among stallions and 5.57 years among mares. The average size of progeny groups was 39.5 offspring per sire and 3.6 offspring per dam. Over the years, the amount of total and four-generation inbreeding steadily increased in the population.

ISSN:0906-4702    

DOI:10.1080/09064709309410138

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The study was conducted using about 93 000 records from the Swedish Sheep Recording Scheme (SRS) during the years 1983, 1985 and 1987. Fleece characteristics studied were: colour of fleece, size of curl, scores for colour, curl distribution and firmness, quality of hair and hair density. Litter size and age of lamb at assessment influenced almost all the fleece traits, and this was consistent over the years. The heritabilities of the fleece characteristics varied between 0.11 and 0.62. No genetic relationships were found between lamb weight at assessment and fleece characteristics. Breeding for heavier lambs can therefore be done without impairing the fleece quality. No unfavourable genetic correlations between the fleece traits were found. The results suggest that the reliability of the fleece inspection from a genetic point of view has not changed much over the last 20 years, although the fleece characteristics have been improved considerably during this period.

ISSN:0906-4702    

DOI:10.1080/09064709309410139

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Field records from Leicester, Texel, Oxforddown, Dorset, Shropshire and Marsh breeds from 1983 to 1989 were used to investigate the influence of environmental factors on weight at birth, 2 and 4 months and 0–60, 0–120 and 60–120 days gain. Significant effects of herd, year, litter size and sex were observed. Generally, lambs born in the middle of the lambing season were heaviest, and postnatal growth decreased with progressing lambing season. Lambs born by yearlings were smaller and had lower growth rates than lambs born by ewes of other age groups. Lambs born by 4–5 year old ewes showed the best performance. Two-way interactions between ewe age, litter size and sex were observed.

ISSN:0906-4702    

DOI:10.1080/09064709309410140

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Egg number (EN42) and egg weight (EW42) in the period between age at first egg and 42 weeks of age (P1) were used as the criteria of selection for ten generations in two specialised lines. Two other lines were selected for an index of egg number and egg weight for four generations, and thereafter these two lines were combined with egg mass in P1(EM42) as the criterion of selection. A random mated control population was also kept throughout the experimental period. Selection for EN42, EW42 and EM42 resulted in a direct cumulative response in generation 10 of about 30 eggs, 16 g of egg weight and more than 1000 g of egg mass in the respective lines in P1. Correlated results in the residual period were generally in good agreement with expectations. Crosses of the two specialised lines were compared with index/egg mass line, and it was concluded that there is an optimum value for the number of generations that the process of crossing the specialised lines is worthwhile, i.e. generation six in our experiment. The changes in the heritability of the various traits were generally in good agreement with theoretical expectations.

ISSN:0906-4702    

DOI:10.1080/09064709309410141

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Three experiments were carried out to study the long-term effects of four combinations of HIGH and LOW concentrate supplementation during the first and second lactation of 72 cows of the Norwegian Red breed: HIGH-HIGH (HH); HIGH-LOW (HL); LOW-HIGH (LH) and LOW-LOW (LL). Basal diets were 0–2 kg hay per cow daily and grass silagead libitum.Compared with HIGH level supplementation, the LOW level cows consumed 0.4 kg DM more forage in the first lactation and 0.4–1.0 kg DM in the second lactation. Milk yield was lower, respectively 2.5 kg and 1.9 kg 4% FCM (fat-corrected milk) daily, between HIGH and LOW in the first and second lactation, with significant cumulative and residual effects from the first to the second lactation. The difference in daily yield was 3.1 kg 4% FCM between HH and LL vs. 1.8 kg between HH and HL. During weeks 1–4 and 5–14 of the second lactation the average daily production was 2.0 and 1.6 kg higher for HH and HL as compared to LH and LL. Milk protein percentage in the second lactation was negatively affected (p<0.05) by LOW supplementation during the first lactation. The highest feed efficiency (kg 4% FCM per FEm) was obtained for LOW concentrate during the first lactation. For both lactations, including the dry period and corrections for body weight changes, efficiency was highest for the cows on HIGH supplementation during the first lactation.

ISSN:0906-4702    

DOI:10.1080/09064709309410142

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The effects of feeding intensity and protein source on growth, feed intake, slaughter and body measurements of 24 pre-pubertal Finnish Ayrshire heifers were studied. The heifers were fed a hay-barley diet supplemented with either urea or rapeseed meal (RSM). The treatments were: (1) LU, low feeding level+urea; (2) LR, low feeding level+RSM; (3) HU, high feeding level+urea; (4) HR, high feeding level+RSM. Hay was fedad libitumon HU and HR diets but was restricted on LU and LR diets. The average initial weight of the heifers was 87 kg, and the final weight 220 kg.

ISSN:0906-4702    

DOI:10.1080/09064709309410143

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The influence of vitamin E supplementation on blood serum vitamin E concentration as well as the seasonal variation of serum vitamin concentration was investigated. Forty horses were divided into a control and three vitamin E supplementation (experimental) groups. The levels of the vitamin E supplementation in the three experimental groups were 1, 3 or 5 mg/kg body weight (bwt) per day. The vitamin was dosed orally. The supplementation was started either at the beginning or in the middle of the indoor (winter) feeding period. There was seasonal variation in the serum vitamin E content; the serum vitamin concentration increased during the grazing and decreased during the indoor feeding period. The basal feeding and a daily supplement of 1 mg/kg bwt were not adequate to maintain or increase the serum vitamin E concentration during the indoor feeding period in an exercising horse. The minimum daily intake of vitamin E would seem to be greater than 1.5 mg/kg bwt. It is suggested that a daily supplement of 3 to 5 mg/kg bwt may be required by horses in training to increase the serum vitamin E levels. This amounts to 1500–2500 mg/day for a horse weighing 500 kg. Supplementation should be started at the beginning of the indoor feeding period.

ISSN:0906-4702    

DOI:10.1080/09064709309410144

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

High amounts of somatic cells in bulk tank milk from dairy herds indicate poor milk quality and low health status. Bulk tank somatic cell counts (BTSCC) are therefore regularly used to encourage good milk quality through price penalties and to detect mastitis problems in the dairy herd. The use of BTSCC for monitoring is complicated by variation and outliers in the data that may mask the changes that should be detected. The Kalman filter, a recursive algorithm for making short-term predictions, is suggested to reduce the noise in BTSCC data. A multi-process Kalman filter with three components applying to (1) normal variation in the data, (2) outliers and (3) abrupt changes in the level of the data is described with updating equations and an example. Retrospective smoothing of the data is also described. A graphical presentation with the smoothed level of historical BTSCC data and forecasted future BTSCC values, both with confidence intervals, is suggested for monitoring purposes.

ISSN:0906-4702    

DOI:10.1080/09064709309410145

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue

ISSN:0906-4702    

DOI:10.1080/09064709309410137

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor