PREWEANING WEIGHT AS A MEASURE OF MILK PRODUCTION IN MICE

1971 ◽  
Vol 13 (2) ◽  
pp. 354-361 ◽  
Author(s):  
J. Nagai
Keyword(s):  
Weight Gain ◽  
Milk Production ◽  
Genetic Parameters ◽  
Litter Weight ◽  
Weight Gains ◽  
Cross Fostering

A cross-fostering experiment with random-bred mice was performed to determine the importance of milk production in 12-day weight of a litter containing either six or eight young and in litter weight gains (litter weight gain from birth to 12 days, and litter weight gain from 1-hour nursing at 12 days). Three and four dams that produced young on the same day formed a cross-fostering set in the six-young and eight-young groups, respectively.In the six-young and eight-young groups, milk production accounted for 65 and 66% of the variance, respectively, in 12-day litter weight. Litter weight gain from birth to 12 days and litter weight gain from 1-hour nursing at 12 days had 74 and 61% of their variance accountable to milk production in both young groups. The findings indicate that the importance of milk production (phenotype) in 12-day litter weight and litter weight gains is virtually the same in the two groups. The conclusion was drawn that unless the values of genetic parameters involved are different for litters of six and eight young, the accuracy of estimating the additive genotype of milk production from 12-day litter weight or litter weight gains is similar when a mother suckles six to eight young.

Genetic relationships between seasonal tissue levels in Scottish Blackface ewes and lamb growth traits

2005 ◽  
Vol 81 (1) ◽  
pp. 11-21 ◽  
Author(s):  
N. R. Lambe ◽  
S. Brotherstone ◽  
M. J. Young ◽  
J. Conington ◽  
G. Simm
Keyword(s):  
Weight Gain ◽  
Birth Weight ◽  
Litter Size ◽  
Growth Traits ◽  
Genetic Relationships ◽  
Genetic Correlations ◽  
Muscle Weight ◽  
Litter Weight ◽  
Weight Gains ◽  
Lamb Growth

AbstractScottish Blackface ewes (no. = 308) were scanned four times per year using X-ray computed tomography (CT scanning) (pre-mating, pre-lambing, mid lactation and weaning), from 18 months to 5 years of age, giving a maximum of 16 scanning events per ewe. Total weights of carcass fat, internal fat and carcass muscle were estimated from the CT images at each scanning event. Lambs produced by these ewes were weighed at birth, mid lactation and weaning to calculate litter growth traits: litter birth weight; litter weight gain from birth until mid lactation; and litter weight gain from birth until weaning. Genetic (rg) and phenotypic (rp) correlations were estimated between ewe CT tissue traits and litter growth traits. Correlations between ewe CT tissue traits and litter size (LS) were also estimated. Ewe CT tissue traits were either unadjusted or adjusted for total soft tissue weight (sum of weights of carcass fat, internal fat and carcass muscle) to investigate relationships with either absolute tissue weights of carcass fat (CFWT), internal fat (IFWT), and carcass muscle (CMWT), or relative proportions of carcass fat (CFP), internal fat (IFP), and carcass muscle (CMP). Litter growth traits were either unadjusted or adjusted for litter size, to investigate relationships with total lamb burden (total litter birth weight (TBW), total litter weight gain from birth until mid lactation (TWGM), total litter weight gain from birth until weaning (TWGW)) or average lamb performance (average lamb birth weight (ABW), average lamb weight gain from birth until mid lactation (AWGM), average lamb weight gain from birth until weaning (AWGW)).Moderate to large positive genetic correlations were estimated between absolute weights of all three ewe tissues (CFWT, IFWT, CMWT), or muscle proportion (CMP), and litter size (LS). Significant positive genetic correlations were also estimated between weight (CMWT) or proportion (CMP) of muscle carried by the ewe pre-mating and total birth weight (TBW) and weight gains (TWGM, TWGW) of her litter, largely due to the associated increase in litter size. Muscle proportion (CMP) was not significantly correlated to average lamb weights or weight gains (ABW, AWGM, AWGW). Pre-lambing carcass fat weight (CFWT) and proportion (CFP) in the ewe showed positive genetic correlations with average lamb weights and weight gains (ABW, AWGM, AWGW), whereas, after lambing, CFP was negatively correlated with these lamb traits. Internal fat weight (IFWT) pre-mating showed positive genetic correlations with all litter growth traits (TBW, TWGM, TWGW, ABW, AWGM, AWGW). Average lamb growth traits were negatively correlated with pre-lambing internal fat proportion (IFP), but positively correlated to IFP at mid lactation and weaning.Correlations were also estimated between each pair of CT traits. Total internal fat weight and total carcass fat weight were very highly correlated (rp= 0·75,rg= 0·96). Correlations with total carcass muscle weight were smaller and positive for both carcass fat weight (rp= 0·48,rg= 0·12) and internal fat weight (rp= 0·42,rg= 0·20).The results suggest that selection for increased carcass muscle weight or proportion in a Scottish Blackface hill flock would have a positive effect on total weights of litters reared, but that selection against carcass fat weight or proportion in a breeding programme for Blackface sheep may have an impact on the maternal ability of the ewe. However, maintaining fat in internal depots may reduce the depletion of carcass fat during pregnancy, allowing this depot to provide energy for lactation, and may have a positive impact on lamb growth.

The effect of year, suckling, dry season and type of dam (ewe or gimmer) on milk production in East African Blackheaded sheep as measured by lamb growth

1966 ◽  
Vol 66 (1) ◽  
pp. 93-95
Author(s):  
G. D. Sacker ◽  
J. C. M. Trail
Keyword(s):  
Weight Gain ◽  
Milk Production ◽  
Live Weight ◽  
Dry Season ◽  
East African ◽  
Live Weight Gain ◽  
Weight Gains ◽  
The Mean ◽  
Lamb Growth ◽  
Lower Production

1. The mean daily live weight gains of lambs were used to estimate the milk production of ewes and gimmers during the first 8 weeks of lactation. Records of 1178 lambings of East African Blackheaded sheep between the years 1952 and 1962 were available.2. Gimmers had significantly lower production than second and subsequent lamb ewes. Ewes rearing twins had a significantly higher yield than ewes rearing singles. There appeared to be no difference in yield between ewes producing twins but rearing singles, and ewes rearing natural singles.3. A long dry season with resultant lowered plane of nutrition significantly reduced the live-weight gain of lambs.

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

2020 ◽  
Author(s):  
Kelsey L Batson ◽  
Hilda I Calderón ◽  
Robert D Goodband ◽  
Jason C Woodworth ◽  
Mike D Tokach ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Litter Size ◽  
Feed Intake ◽  
Control Diet ◽  
Net Energy ◽  
Weaning Weight ◽  
Litter Weight ◽  
Dietary Treatments ◽  
Cross Fostering

Abstract A total of 109 sows (Line 241; DNA, Columbus, NE) were used to evaluate the effect of increasing dietary phytase in lactation diets, already adequate in P, 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 Hi Phos GT 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 phytase diets that contained 1,000 or 3,000 FYT/kg were also formulated to 0.50% STTD P and 0.62% STTD Ca including the release of 0.132% STTD P and 0.096% STTD Ca. Diets were balanced for net energy and fed from d 107 of gestation until weaning (d 18 ±3). All farrowings were monitored, with farrowing duration starting at the time the first pig was born until the first dispersal of placental tissues with no subsequent pigs born. Litters were cross-fostered within treatment until 48 h post-farrowing to equalize litter size. There were no differences among treatments in sow body weight at d 107 of gestation, 24-h after farrowing, or at weaning. Sow average daily feed intake from farrowing to weaning tended to increase (linear, P = 0.093) as phytase increased. There was no evidence for difference in the number of total born pigs, as well as the percentage of stillborns, mummies, and born alive pigs at the completion of farrowing. Similarly, phytase supplementation did not influence (P > 0.05) wean-to-estrus interval or litter size after cross-fostering among dietary treatments. Although not significant (linear, P = 0.226), farrowing duration decreased as added phytase increased with a decrease of 47 minutes (12%) for 3,000 FYT compared to the control. There were no differences in pig weight at weaning, but as a result of increased survivability (linear, P = 0.002), litter weaning weight and overall litter weight gain increased (quadratic, P < 0.05) up to 1,000 FYT of added phytase with no further benefit observed in sows fed 3,000 FYT. In conclusion, sow feed intake tended to increase linearly with increasing added phytase. Feeding 1,000 FYT/kg maximized overall litter gain and weaning weight; however, a larger scale study with more sows is needed to determine the addition of phytase in lactation diets to reduce farrowing duration.

The role of growth hormone, prolactin and insulin-like growth factors in the regulation of rat mammary gland and adipose tissue metabolism during lactation

1992 ◽  
Vol 135 (2) ◽  
pp. 195-202 ◽  
Author(s):  
M. C. Barber ◽  
R. A. Clegg ◽  
E. Finley ◽  
R. G. Vernon ◽  
D. J. Flint
Keyword(s):  
Adipose Tissue ◽  
Mammary Gland ◽  
Lipid Metabolism ◽  
Weight Gain ◽  
Lipoprotein Lipase ◽  
Milk Production ◽  
Secretory Cells ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Litter Weight

ABSTRACT Inhibition of prolactin secretion with bromocriptine and neutralization of GH action with a specific antiserum to rat GH (rGH) were used to explore the modes of action of GH and prolactin in maintaining lactation in the rat. Treatment of dams with anti-rGH caused a small reduction in litter weight gain whilst bromocriptine reduced litter weight gain by 50%. When both treatments were combined, however, milk yield ceased completely and this wasaccompanied by a wide variety of effects on mammary lipid metabolism including decreases in the mRNA concentrations of acetyl CoA carboxylase, fatty acid synthase, malic enzyme and lipoprotein lipase. Activities of acetyl CoA carboxylase and lipoprotein lipase were also significantly reduced. Reciprocal changes were evident in adipose tissue with increases in acetyl CoA carboxylase and lipoprotein lipase activities. In conjunction with a decreased lipolytic response to noradrenaline in adipose tissue of animals given the combined treatment of bromocriptine and anti-rGH, this represented a co-ordinated series of changes to reduce lipid synthesis in the mammary gland and enhance lipogenesis and triglyceride storage in adipose tissue as milk production ceased. All of these effects could be prevented in part by concurrent treatment with GH, but insulin-like growth factor-I (IGF-I) and IGF-II failed to affect any of the parameters measured. Taken as a whole, these data suggest that (1) both prolactin and GH induce a co-ordinated series of changes in the mammary gland, (2) the intracellular controls involved clearly operate at the level of gene transcription although post-translational controls are also probably involved, (3) the effects of GH on the mammary gland could not be mimicked by IGFs and (4) although GH clearly regulates lipid metabolism in adipose tissue in a manner which should favour nutrient utilization by the mammary gland, these effects are probably too small to account for the effects of GH on milk production. Since GH receptors have not been reported to be present on mammary secretory cells, the precise mode of action of GH remains uncertain. Journal of Endocrinology (1992) 135, 195–202

scholarly journals The Impacts of Waterproof Insulated Jackets on Lamb Performance on a UK Lowland Farm

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 217
Author(s):  
Eleanor Brooke Collins ◽  
Nicola Blackie
Keyword(s):  
Weight Gain ◽  
Cold Stress ◽  
Morbidity And Mortality ◽  
Daily Weight Gain ◽  
Birth Date ◽  
Body Temperatures ◽  
Average Daily Weight Gain ◽  
Treatment Groups ◽  
Surface Temperatures ◽  
Weight Gains

The majority of lamb losses occur within the first two weeks of life, with cold stress being a major cause of lamb morbidity and mortality. This study investigated the effect of insulating lamb jackets on newborn lambs. One hundred and four newborn lambs were randomly allocated by birth date to two treatment groups, (a) non-jacketed (n = 52) or (b) jacketed (n = 52), for fourteen days after birth. The live weights of lambs were recorded regularly up to 21 days, and average daily weight gains were calculated from these data. For the first two days after recruitment to the study, surface and body temperatures of lambs were also recorded. The jackets significantly increased the lambs’ surface temperatures, providing a warmer microclimate and reduced cold stress for jacketed lambs. There was no significant effect of the insulating jackets on estimated body temperatures, live weights or average daily weight gain of the lambs in this study. There were no detrimental effects of the jackets, and no rejection of lambs occurred.

The effect of winter food level on compensatory growth of weaned, suckled calves grazed at two sward heights

1986 ◽  
Vol 43 (2) ◽  
pp. 211-223 ◽  
Author(s):  
I. A. Wright ◽  
A. J. F. Russel ◽  
E. A. Hunter
Keyword(s):  
Weight Gain ◽  
Compensatory Growth ◽  
Live Weight ◽  
Food Level ◽  
Live Weight Gain ◽  
Subsequent Performance ◽  
Herbage Intake ◽  
Winter Food ◽  
Weight Gains ◽  
Winter Feeding

ABSTRACTTwo experiments were conducted with weaned, suckled calves to investigate the effect of feeding level during the post-weaning winter on their subsequent performance when continuously grazed on pasture maintained at two sward heights. Low, medium and high levels of winter feeding resulted in winter live-weight gains of 0·31, 0·58 and 0·79 (s.e. 0·027) kg/day (P < 0·001) during the 152-day winter in experiment 1 and 0·44, 0·69 and 0·84 (s.e. 0·029) kg/day (P < 0·001) for 189 days in experiment 2. During summer (93 days in experiment 1 and 87 days in experiment 2) there was a significant effect of winter food level on performance when live-weight gains were 1·10, 1·02, 0·87 and 1·35, 1·23 and 1·19 (s.e. 0·060) kg/day for the low, medium and high winter food levels on the short and tall swards respectively in experiment 1 (P < 0·01) and 0·86, 0·66, 0·51 and 1·26, 1·18 and 0·91 (s.e. 0090) kg/day in experiment 2 (P < 0·001). The cattle showing compensatory growth had higher herbage intakes and it is postulated that this occurred because of a negative association between body fat and herbage intake. Sward height had a large positive effect on herbage intake and live-weight gain and it is concluded that for maximum intake on ryegrass swards, herbage height should be at least 8 cm. Lower levels of winter live-weight gain delayed the time to slaughter, but allowed cattle to achieve heavier carcass weights at a fixed level of fatness.It is concluded that there is no single optimum winter food level for weaned, suckled calves but that the choice will depend upon several factors, including availability of winter and summer food resources, the length of the winter feeding period, the desired date of slaughter and type of carcass to be produced.

Effects of nutrition in late pregnancy on subsequent milk production in Ewes

1970 ◽  
Vol 12 (1) ◽  
pp. 23-36 ◽  
Author(s):  
T. T. Treacher
Keyword(s):  
Milk Production ◽  
Dry Matter ◽  
Live Weight ◽  
Late Pregnancy ◽  
Lower Content ◽  
Weight Changes ◽  
Total Birth ◽  
Weight Gains ◽  
Ad Libitum ◽  
Voluntary Intake

SUMMARY1. Scottish Half-bred ewes carrying twin foetuses were fed individually to make live-weight gains in the last six weeks of pregnancy of (1) 20%, (2) 10% and (3) 0% of their live weight in week 14 of pregnancy. In lactation the ewes were fed ad libitum. The lambs were removed 12 to 16 hr after parturition and the ewes were machine-milked twice daily for the first six weeks of lactation.2. Total birth weights per ewe of twin lambs from the treatments were (1) 10·10 kg, (2) 9·44 kg and (3) 8·18 kg and differed significantly.3. The level and pattern of voluntary intake in lactation did not differ significantly between the treatments. Total dry-matter intakes in the six weeks of lactation were (1) 121·9 kg (2) 105·9 kg and (3) 109·5 kg.4. The pregnancy treatments affected the level of milk production and the shape of lactation curves. The total yields in the first six weeks of lactation were (1) 58·8 kg, (2) 43·5 kg and (3) 26·9 kg. Higher contents of fat and protein and the lower content of lactose in the milk from treatment-3 ewes on days 1 and 3 of lactation indicated a slower onset of lactation in these ewes. Between days 7 and 35 of lactation the contents of fat and SNF were lowest on treatment 3 but the differences were not significant.5. The live-weight changes in lactation, which were in inverse order to the gains in late pregnancy, were (1) 3·4 kg, (2) 5·5 kg and (3) 9·5 kg.

scholarly journals Estimates of genetic parameters and eigenvector indices for milk production of Holstein cows

2013 ◽  
Vol 96 (11) ◽  
pp. 7284-7293 ◽  
Author(s):  
R.P. Savegnago ◽  
G.J.M. Rosa ◽  
B.D. Valente ◽  
L.G.G. Herrera ◽  
R.L.R. Carneiro ◽  
...  
Keyword(s):  
Milk Production ◽  
Genetic Parameters ◽  
Holstein Cows
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