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PubMed1999

[Iodine deficiency, iodine requirement and iodine excess of farm animals--experiments on growing pigs].

Since insufficient iodine intake is widespread among the German population, farm animals should if possible receive iodine above requirement, thus concentrating the trace element in milk, eggs and possibly meat. Experiments with a total of 29 fattening pigs with grain soy-bean meal diets without iodine supplementation or with increasing supplements up to 1000 micrograms iodine/kg diet did not show any effect on growth intensity (gain) and feed efficiency. At and above 125 micrograms supplementary iodine/kg diet the thyroid was not or only little hypertrophied and iodine incorporation into thyroglobulin sufficed to sustain serum T4 concentration. The glucosinolates of rape feeds increase iodine requirement. In an experiment with a total of 36 fattening pigs the thyroid iodine depot was decreased due to rapeseed meal feeding, this in agreement with antithyroid drugs which had been also tested. A thyroid with emptied iodine depot is hardly able to synthesize and release hormone, the serum thyroxine concentration showed a drastic decrease. More iodine may compensate for effects of glucosinolates, however, only with not too much of these compounds in the feed. Excessive iodine dosages (10 mg/kg diet) were compared with supplements in the range of recommendations (100 and 1000 micrograms/kg diet) with a total of 120 pigs in three groups of 40 animals each. The dosage of 10 mg iodine/kg diet decreased serum T3 concentration. The enlarged thyroid with double weight had a very high iodine concentration. In comparison with physiological application (100 or 1000 micrograms iodine/kg diet) the thyroid deposited only little iodine in the group with the excessive iodine intake related to consumed iodine quantity. In case of sufficient and excessive iodine supply--industry of compounds feed applies up to 2.5 mg supplementary iodine/kg diet--T4 and iodine of serum but also thyroid weight cannot serve as markers. This range of usual iodine supply is better characterized by the iodine depot of the thyroid. As a rule, thyroid weight increase indicates glucosinolate effects, generally those of dietary antithyroid compounds, more seldom it shows extreme and longterm iodine undersupply or iodine excess.

Animal Feed↗

PubMed2002

Feeding behaviour of infants with cleft lip and palate.

AIM: To determine whether the feeding behaviour of infants with cleft lip and palate is improved with a type-P teat, which is widely used in Japan by such infants, compared with a standard teat. The difference in intra-oral movements between the type-P teat, modified for the evaluation of feeding behaviour, and an unmodified type-P teat was also compared using ultrasonography. METHODS: In part 1 of the study, 15 infants aged 2 to 3 mo and 7 infants aged 2 wk were evaluated for sucking pressure, expression pressure, frequency and duration of sucking. All the infants had a complete unilateral cleft lip and palate without any other abnormalities. In part 2, an ultrasonographic analysis of intra-oral movement was done for 5 infants enrolled in part 1 of the study. RESULTS: Sucking pressure did not occur in all infants. It was found that feeding efficiency improved with the type-P teat compared with the standard teat. The expression pressure with the type-P teat was significantly higher than that with the standard teat, and the feeding frequency with the type-P teat was lower than that with the standard teat. CONCLUSION: A type-P teat is suitable for infants with cleft lip and palate who have sucking difficulties. However, a type-P nipple with a squeezable bottle does not fully solve the feeding problems of infants with cleft lip and palate. New artificial teats that allow a higher expression pressure are desirable, and the measurement of the expression pressure may be helpful in the evaluation of artificial nipples.

Cleft Lip↗

PubMed1998

Effect of dietary oils, cholesterol and antioxidant vitamin supplementation on liver microsomal fluidity and xenobiotic-metabolizing enzymes in rats.

This study was undertaken to compare the effects of four oils: corn (C), olive (O), hazelnut (H) or fish (F), and the intake of two supplements: cholesterol, 1% (Ch) or dl-alpha-tocopherol acetate, 500 mg/kg, and beta-carotene, 30 mg/kg (V), on liver microsomal fluidity, cyt P450 content and aniline hydroxylase (AH), aminopyrine-N-dimethylase (AND) and UDP-glucuronyltransferase (UDP-GT) activities. Male Sprague-Dawley rats (n = 6/group) were fed semipurified diets containing 15% oil, without or with Ch or V, for 20 days. Dietary intake and feed efficiency were lower in rats fed F. Relative liver weight was higher in animals fed F, similar in O and H, and lower in the group fed C. The intake of V increased feed intake in C+V group and decreased the relative liver weight of F+V group, which also decreased with the intake of F+Ch. Ch intake increased the relative liver weight in all groups consuming vegetable oils. Cyt P450 content was higher in rats fed F. Decreased cyt P450 content was observed in C+Ch and F+Ch groups, while it augmented in H+Ch group. Mixture V increased cyt P450 in rats fed C+V, F+V and O+V. The highest membrane fluidity was observed in rats fed F. Fluidity was also higher in group H versus O or C. The intake of Ch decreased microsomal fluidity in all groups, while V induced an increase in microsomal fluidity in group O+V. Rats fed F exhibited higher enzyme activities. AND activity increased with V only in rats fed H+V, while AH activity increased with V intake in groups F+V and O+V. In the C+V group, fluidity was not affected by V, while the cyt P450 content and UDP-GT activity increased. The O+V group exhibited lower UDP-GT activity and higher fluidity and cyt P450 content. The activity of AH decreased in groups F+Ch and C+Ch. UDP-GT activity was higher in rats fed F. It diminished after the intake of Ch in H+Ch and F+Ch. These results indicate that although AH and AND act in the same microsomal metabolic pathway, their localization into the membrane may be determinant of their activity and the response to dietary lipids. It is shown that F intake exerts the most significant effects upon liver microsomal properties, e.g. higher fluidity, cyt P450 content and enzymatic activities, an effect that prevails over the intake of the supplements tested.

Animals↗

PubMed1996

Efficacy of supplemental 1 alpha-hydroxycholecalciferol and microbial phytase for young pigs fed phosphorus- or amino acid-deficient corn-soybean meal diets.

Young pigs (5 wk of age and 8 kg) were used to test the efficacy of 1 alpha-hydroxycholecalciferol (1 alpha-OH D3) and microbial phytase for improving the utilization of phytate phosphorus (P) and amino acids present in corn-soybean meal (SBM) diets. Phytase supplementation (1,200 units/kg) to a vitamin D3-adequate, P-deficient corn-SBM diet elicited a marked response (P < .05) in weight gain and ash content of fibula, scapula, and metatarsal bones, but dietary addition of 1 alpha-OH D3 (20 micrograms/kg) was without effect. A P- and vitamin D3-adequate, amino acid-deficient corn-SBM diet (15.5% CP) also was supplemented with 1,200 units/kg of phytase to evaluate the efficacy of phytase in improving amino acid utilization. Pigs gained faster (P < .05) and more efficiently (P < .05) when this diet was supplemented with limiting amino acids, and phytase addition also increased (P < .05) weight gain, regardless of whether the diet was deficient or adequate in amino acids. Feed efficiency was improved (P < .05) by phytase addition to the amino acid-deficient diet but not to the amino acid-adequate diet. Pigs fed the low-CP, amino acid-fortified diet gained as fast and as efficiently as those fed a 19.5% CP (1.19% lysine) positive-control diet.

6-Phytase↗

PubMed1978

The response of Bobwhite quail chicks to dietary ammonium and an antibiotic-vitamin supplement when fed B1 aflatoxin.

Dietary ammonium phosphate and a water soluble antibiotic-vitamin supplement were tested as possible means of preventing or minimizing the effects of aflatoxin in the diet of Bobwhite quail chicks. Aflatoxin (B1) was added to the diet at levels of 0, 0.4 and .8 ppm in Experiment 1 and 0, .8 and 1.2 ppm in Experiment 2. In addition, ammonium phosphate was included in the diet at levels of 0 or 1.46% and an antibiotic-vitamin supplement was added to the drinking water at 0 or 600 mg/liter. All treatments were given from 1 to 32 days of age in Experiment 1 and 1 to 28 days of age in Experiment 2. The addition of aflatoxin to the diet resulted in decreased body weight, feed consumption and percent tibia ash, increased mortality and increased feed required per unit of body weight. The addition of ammonia to the diet in the form of monoammonium phosphate did not alleviate the effects of aflatoxin. Water supplementation with an antibiotic-vitamin mixture improved weight and feed efficiency and decreased mortality of chicks receiving aflatoxin.

Aflatoxins↗

PubMed2001

Evaluation of nutritive value and functional qualities of sorghum subjected to different traditional processing methods.

Sorghum (Sorghum bicolar L. Moench), a staple food in many parts of the world, is underutilised compared to its potential due to inherent problems. A study was conducted to evaluate the effect of different traditional processing methods on the nutritional and functional qualities of sorghum. The review of literature established the main causes of the low level of sorghum utilisation to be low nutritional and inferior organoleptic qualities. It was further established that traditional processing methods, such as germination and fermentation, can promote its utilisation. Three processing methods, namely germination (G), fermentation (F), and germination combined with fermentation (GF), were used to prepare feeds from two sorghum varieties, Tegemeo and Udo. Evaluation of the feed qualities in terms of acceptability, retention, feed efficiency ratio (FER) and protein efficiency ratio (PER), using weanling rats was carried out and compared to the untreated one which served as control. An element of functional properties was assessed in terms of diastatic power (DP). Regarding feed intake, there was no significant difference between the feeds. Body retention for Tegemeo variety was higher than that for Udo. FER ranged from 0.019 +/- 0.015 to 0.095 +/- 0.015, PER ranged from 0.113 +/- 0.089 to 0.703 +/- 0.111 and diastatic power from 15.99 +/- 1.20 to 114.58 +/- 0.95. In all the three cases, germinated feeds had the highest values and were therefore considered of higher nutritional value. It was therefore concluded that germination was superior to the other processing methods in improving the nutritional and functional qualities of sorghum.

Analysis of Variance↗

PubMed1975

[Limiting amino acids of chickpeas (Cicer arietinum) for chickens and pigs].

Three experiments, two with broilers and one with pig, were conducted to determine the limiting amino acids of chickpea (Cicer arietinum). In the first 15% protein diets based on autoclaved chickpea were supplemented with methionine (0.20%), either alone or combined with threonine (0.025%) with no significant effect on growth or feed convertion of chicks; however, the addition of methionine tended to improve both parameters in relation to the unsupplemented diet. In the second experiment methionine (0.20%) and/or tryptophan (0.03%) were added to 15% protein diets based on either raw or autoclaved chickpeas. Cooking improved growth and feed efficiency in relation to the raw controls (P less than .05); methionine supplementation was beneficial for both raw and autoclaved diets (P less than .01); the addition of tryptophan was favourable only for the cooked chickpeas. A third experiment was conducted with weanling pigs to study the effect of methionine supplementation to sorghum-chickpea diets with 14 and 12% protein. In both cases, the addition of the sulphur amino acid improved growth and efficiency to the levels obtained with a 15.34% protein sorghum-soybean meal control.

Amino Acids↗

PubMed1995

Long-term weight cycling reduces body weight and fat free mass, but not fat mass in female Wistar rats.

OBJECTIVE: The effects of repeated weight gain and loss, the weight cycling (WC) phenomenon, on body composition have been controversial. WC history and age are two confounding factors which may contribute to this inconsistency. In the present investigation, we examined the effects of WC on body weight regulation, body composition and feeding efficiency in a long-term study when WC history was controlled. METHOD: Six groups of female Wistar rats were used in this study. Five of these six groups were made obese by feeding a high fat (HF) diet for 11 weeks and then divided into five groups: non-cycling control group (HFCON); one group which cycled three times (HFCYC); and three one-cycle groups which cycled only once corresponding to each of the three cycles in the HFCYC group. The sixth group was fed the low fat diet without cycling (LFCON). Weight cycling (WC) was produced by feeding 50% of a HF diet with extra protein, vitamin and mineral mixture until body weight of the cycled groups reached the level of the LFCON group. After three cycles (52-56 weeks), all rats were killed. RESULTS: Results showed that repeated WC reduced final body weight and fat free mass, but not body fat mass in the HFCYC group. Repeated WC also reduced rate of weight regain. During the third cycle, the amount of fat regained during refeeding was more than the fat mass lost during restricted feeding in the HFCYC group. For the three one-cycle groups, the rate of weight regain was slower but rate of weight loss was the same in older rats as in the younger rats. CONCLUSION: Thus repeated WC may favor more body fat retention in later cycles. Aging affected rate of weight regain but not rate of weight loss, nor body composition, while repeated WC affected both rate of weight loss and regain.

Animals↗

PubMed2001

Porcine growth hormone: a central metabolic hormone involved in the regulation of adipose tissue growth.

During the past 20 y, much has been learned about how porcine growth hormone (pGH) affects growth and nutrient partitioning in growing pigs. Our contemporary understanding of the biology of pGH has as its roots the seminal studies conducted by Larry Machlin. His studies and many subsequent reports by other investigators have established that treatment of growing pigs with pGH markedly stimulates muscle growth and, concurrently, reduces fat deposition. In growing pigs, maximally effective doses of pGH increase average daily gain as much as 10% to 20%, improve feed efficiency 15% to 30%, decrease adipose tissue mass and lipid accretion rates by as much as 50% to 80%, and concurrently increase protein deposition by 50%. These effects are associated with a decrease in feed intake of approximately 10% to 15%. These responses occur because pGH has a wide array of biological effects that modulate nutrient partitioning between adipose tissue and skeletal muscle. The decrease in adipose tissue growth is due to a reduction in lipogenesis that is the consequence of pGH blunting the effects of many insulin-dependent events. This article provides an overview of some of the biological effects pGH has in adipose tissue and discusses what is known about the underlying mechanisms that account for these effects.

Adipose Tissue↗

PubMed1980

The requirement and toxicity of selenium in rainbow trout (Salmo gairdneri).

This study measured the dietary selenium requirement of rainbow trout and their response to excessive levels of dietary selenium. A dietary selenium level of 0.07 microgram/g dry feed with a waterborne selenium level of 0.4 +/- 0.2 microgram/liter and a dietary vitamin E level of 0.4 IU/g dry diet was sufficient to prevent frank selenium deficiency symptoms. Maximal plasma GSH.px activity was obtained at a dietary selenium level between 0.15 and 0.38 microgram/g dry feed which is less than the average selenium concentration of commercial diets. Chronic dietary selenium toxicity occurred at 13 microgram selenium/g dry feed. Major effects of selenium toxicity were reduced growth rate, poor feed efficiency and a high number of mortalities. No histopathological lesions or significant deviation in the investigated blood parameters or liver somatic index were detected in trout raised on diets containing 13 microgram selenium/g dry feed. Tissue selenium analysis indicated that trout can maintain homeostasis with dietary selenium levels up to 1.25 microgram/g dry feed. The selenium uptake and accumulation in tissues of trout reared on diets containing in excess of 3 microgram/g dry feed may ultimately be toxic to trout if maintained over long periods of time.

Animals↗

PubMed1996

Economic viability of crosses of Bos taurus and Bos indicus for dairying in warm climates.

Countries in the warm climatic zones need greater domestic supplies of milk. To increase yields, the option that is least expensive and most widely used is to cross dairy breed sires with local cattle. First generation crosses have more vigor than other crosses under stressful environmental conditions; growth rate, milk yield, and reproduction rate exceed those of local breeds and other crossbred combinations. On average, lactating first generation crosses are fed energy at 45 to 60% below their potential response, which limits their capabilities. Other crosses with local breeds fall short of first generation crosses as do some of the present synthetic breeds with 5/8 to 3/4 dairy breeding. Well-fed (> 2.5 maintenance needs) Holstein or Jersey crosses containing 1/4, 1/2, or 3/4 Bos indicus (Zebu) tend to follow projections of parental means for milk yield, reproduction rate, and tolerance to heat stress; however, for crosses, losses exceed predictions for lactation length, persistency of milk yield, feed efficiency, and rate of milking. Size of thoracic and abdominal organs, size of endocrine glands, stomach weight, and intestine length are lower than expected compared with values for purebreds. The smaller digestive system affects feeding intake of B. indicus crosses, and the smaller endocrine glands appear to limit responses to high energy diets. Possible directional dominance of B. indicus needs further investigation. The first generation crosses could support their use for dairy purposes if feeding rate and management were optimal, but prospects for other crosses remain questionable.

Animal Feed↗

PubMed1986

Total substitution of leaf protein in the ration of laying hens.

Laying birds of the Harco strain (crossbred sex-linked Brown Leghorn and Rhode Island Red) were fed rations in which leaf protein replaced 0, 25, 50, 75, and 100% of the soybean meal. These five rations were compared with a standard layer ration that contained fish meal and ground nut cake. The results show that 75% of the soybean meal in layer rations can be replaced by leaf protein without any significant effect in egg production and feed efficiency when compared with the performance of birds receiving fish meal in their diet. Use of leaf protein as the sole supplemental source of protein for the birds significantly (P less than .05) reduced feed intake and also resulted in production of very watery droppings by the birds. Feeding of leaf protein also significantly (P less than .01) increased yolk color score.

Animal Feed↗

PubMed1988

Anticoccidial efficacy of narasin in floor pen trials.

Narasin is effective against all species of chicken coccidia when tested in short-term battery cage experiments. The efficacy of narasin at concentrations of 20, 40, 60, 80, and 100 ppm was evaluated in ten floor pen trials in which commercial broiler production conditions were simulated. To provide intentional exposure to different levels of coccidia challenge, the litter of some pens was seeded with oocysts of each of the pathogenic species of chicken coccidia, whereas some pens were left nonseeded. Weight gain, feed efficiency, and lesion score data from the ten trials were analyzed as one randomized block experiment. Medication with narasin resulted in a significant reduction in lesion scores and significant improvement in weight gain and feed:gain ratios when compared with scores and gain of nonmedicated controls for both seeded and nonseeded pens. Each increase in narasin concentration up to 100 ppm for the seeded pens and up to 80 ppm for the nonseeded pens resulted in a significant reduction in cecal lesion scores. Although maximum weight gain in the seeded pens was obtained with 40 ppm narasin, concentrations greater than or equal to 60 ppm narasin were significantly better than the 40 ppm concentration in improving feed:gain ratios. These results confirm the effectiveness of narasin in controlling coccidiosis in broilers exposed to oocysts in the litter of floor pens. Furthermore, a clear relationship between the response to narasin and the level of oocyst challenge was demonstrated.

Animals↗

PubMed1999

Patterns of growth and feed intake in divergent lines of laying domestic fowl selected for residual feed consumption.

At Generations 15 (males) and 18 (females) of a divergent selection experiment on residual feed consumption (RFC) in laying poultry, patterns of growth, feed consumption, and associated traits were monitored between the ages of 4 and 34 wk. This monitoring was done to determine how the well-established RFC and feed intake (FI) divergences between adults of the low intake R- line and of the high intake R+ line took place, in relation to the evolution of correlated traits. In males and females, BW and BW gain were higher in the R- line in the first weeks of test, but patterns of BW were quite similar in both lines afterwards. However, R- hens remained heavier than R+ females to the end of the experiment. Line difference for BW was achieved by 28 wk of age, at 2,974 and 2,094 g, and the R- line was then 135 and 133 g heavier, respectively, for males and females. After a fast initial increase in both sexes, FI diverged quickly around 16 to 18 wk of age (sexual maturity), to attain 13 g/d in males and 28 g/d in females, well before the end of the experiment. At the same time, a divergence was observed for wattle length, which was 21% higher in R+ females. Residual feed consumption gradually diverged in the two lines, and the difference became significant at 14 wk of age. At the same age, shanks were 8% longer in R+ hens. Finally, levels of triiodothyronine decreased faster in the R- line, as FI divergence was increasing. These results indicate that the RFC difference between R- and R+, lines obtained in adult birds by divergent selection lines, starts somewhat early in life. In addition, the RFC difference appears to be associated with specific growth periods, around 14 wk and 18 to 20 wk. It is at this time that large differences appear in morphological traits involved in body heat loss. No significant correlations were found between early (6 wk) measures of FI, feed efficiency, and RFC, with adult values (32 to 34 wk) for RFC and FI.

Animals↗

PubMed1979

[Addition of amino acids and oligopeptides to the diet of piglets. I. Effects on productive performance and development of intestinal microbial flora].

The effects in connection with the addition of small quantities of aminoacid and oligopeptide pools to balanced diets were studied on 36 male piglets, divided into three groups (1: control; 2: aminoacid pool; 3: aminoacid and oligopeptide pool). Piglets receiving the aminoacid pool (group 2) exhibited better performances: an increased weight gain resulting in higher feed efficiency and an increased overall microbial count with a predominance of the useful population.

Amino Acids↗

PubMed2006

The relationship between residual feed intake and feed intake behavior in group-housed Duroc barrows.

Because feed is the major input in pork production, conversion of feed into lean tissue at minimum costs has been a focus for improvement. Several researchers have proposed using residual feed intake (RFI) rather than feed conversion ratio (FCR) for genetic improvement of feed efficiency. Little is known about the variation in RFI in pigs. As several studies suggest a greater RFI is related to greater animal activity levels, the current study investigated the phenotypic relationship between RFI and feed intake (FI) behavior of 104 group-housed growing Duroc barrows allowed ad libitum access to feed. Feed intake, BW gain, feeding time (TIME), feeding frequency (VISITS), RFI, and FCR were calculated for 5 periods of 14, 23, 28, 21, or 23 d in length (periods 1 through 5, respectively) on animals that were between 73 to 95 d of age at the start of the testing period. Barrows that grew faster consumed more feed (P < 0.001), and barrows that consumed more feed were fatter (P < 0.01). There were no correlations between VISITS and TIME, between VISITS and FI, or between VISITS and RFI. Barrows that spent more time at the feeder, however, consumed more feed (P < 0.05) and had greater RFI in periods 1, 3, and 5 (P < 0.05). As expected, FI and FCR were highly correlated with RFI (P < 0.001). These results suggest that a greater FI rather than greater feed intake activity resulted in greater RFI values.

Animal Husbandry↗

PubMed2001

Effect of weaning status and implant regimen on growth, performance, and carcass characteristics of steers.

One hundred forty-three Angus x Simmental crossbred steers (initial BW = 155.1 +/- 4.5 kg) were used in a 2-yr study (yr 1, n = 67; yr 2, n = 76) to determine the effects of weaning age, implant regimen, and the weaning age x implant regimen interaction on steer growth and performance, organ mass, carcass characteristics, and cooked beef palatability. Steers were early-weaned at an average age of 108 d (EW) or normally weaned at an average age of 202 d (NW) and allotted by weight to an aggressive or nonaggressive implant regimen. On their respective weaning dates, EW and NW steers were penned individually and fed a grain-based diet until they were slaughtered at a final BW of 546 kg. A subsample of steers (n = 2 per treatment) were slaughtered at 254 kg. At 254 kg, EW steers implanted with the aggressive implant regimen had 64% greater backfat depth than those implanted with the nonaggressive implant regimen; conversely, NW steers implanted with the aggressive implant regimen had 52% lower backfat depth than those implanted with the nonaggressive implant regimen (weaning status x implant regimen interaction; P < 0.01). A similar interaction was observed for empty visceral organ weights. Early-weaned steers were younger (354.7 vs 372.4 d; P < 0.01) at final slaughter but were in the feedlot longer (246.5 vs 169.6 d; P < 0.01) than NW steers, whereas the aggressive implant regimen decreased days fed (203.3 vs 212.7; P < 0.07) compared to the nonaggressive implant regimen. Overall ADG was greater for EW than for NW steers (1.61 vs 1.50 kg/d; P < 0.01) and for the aggressive compared with the nonaggressive implant regimen (1.59 vs 1.52 kg/d; P < 0.02). Early-weaned steers consumed less DM per day (7.4 vs 8.5 kg/d; P < 0.01) and were more efficient (0.217 vs 0.208 kg/kg; P < 0.02) but consumed more total DM (1,817 vs 1,429 kg; P < 0.01) than NW steers while in the feedlot. Implant regimen did not affect DMI (P > 0.37) or feed efficiency (P > 0.15). Weaning status did not affect carcass characteristics (P > 0.14), final empty body composition (P > 0.25), or final longissimus muscle composition (P > 0.18); however, steaks from EW steers had higher (P < 0.05) taste panel tenderness and juiciness ratings than steaks from NW steers. The aggressive implant regimen decreased yield grade (P < 0.02), but did not affect quality grade (P > 0.86) compared to the nonaggressive implant regimen. Placing early-weaned steers on an aggressive implant regimen is a viable management option.

Age Factors↗

PubMed1983

Breed, heterotic and diet effects on postweaning litter growth and mortality in rabbits.

The effects of sire breed, dam genetic group and diet on postweaning litter growth and mortality were evaluated in 208 litters of rabbits. Sire breeds were New Zealand White (NN), California (CC) and Flemish Giant (FG). Dam genetic groups were NN and CC straightbred and California X New Zealand White (CN) and New Zealand White X Californian (NC) reciprocal crossbreds. Litters were fed either a commercial diet or a 74% alfalfa diet. Litter size and weight at 56 d and litter gain (the difference between 56- and 28-d litter weights) tended to be lower in NN- compared with CC-sired litters; while feed intake was significantly lower and mortality was higher in progeny of NN sires. Litter 56-d weight, litter gain and litter feed efficiency (gain/feed intake) were improved (P less than .05) in litters sired by FG vs NN or CC bucks. Direct heterosis (CN and NC compared with NN and CC litters) for litter size, growth and feed-related traits was generally low (less than 11% in absolute value), while moderate heterosis levels (-21 and -22%) were observed for diarrhea-related and total mortality. Differences between NN and CC straightbred dams for litter size and weight at 56 d and litter gain were small, but in favor of NN dams. Diarrhea-related and total mortality were higher (P less than .05) in litters reared by NN vs CC straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗