Three experiments were conducted to determine the effects of dietary
supplementation with a novel antimethanogenic compound (AM) on methane
production and growth in Brahman (Bos indicus) steers.
The compound was a chemical complex of bromochloromethane (BCM) and
α-cyclodextrin, which is chemically stable when added to feed, thus
overcoming the highly volatile nature of BCM. In these experiments the AM
compound was administered to steers as a mixture with different feed
supplements.
In Expt 1 the effect on in vivo methane production of
feeding steers the AM compound was determined using a confinement-type
respiration chamber. Methane production of AM-treated steers (0 ±
2·4 mL/min) was lower (P < 0·001)
than that of control steers (205 ± 5·2 mL/min) over 28 days.
In Expt 2 we determined the effect of AM treatment over 12 weeks on growth of
steers fed on a low quality roughage diet. The most marked effect of AM
treatment was reduced (P < 0·01) voluntary
roughage dry matter intake (DMI), and reduced (P <
0·01) acetate : propionate molar ratio (A : P) in rumen fluid. Average
daily liveweight gain (ADG) (0·22 ± 0·01 kg/day) and
feed : gain ratio (F : G) (20·7 ± 1·46 kg DMI/kg
liveweight) were not significantly affected by AM treatment.
In Expt 3 we determined the effect of AM treatment over 10 weeks on growth of
steers fed on a medium quality roughage diet, in steers that were either
treated or not treated with a hormonal growth promotant (HGP; oestadiol
17β). AM treatment reduced (P < 0·05) DMI
below that of steers not treated with AM, whereas DMI was not significantly
affected by HGP treatment. Both AM (P < 0· 1)
and HGP (P < 0·05) treatments separately
reduced A : P ratio in rumen fluid. AM treatment had no significant effect on
ADG, whereas ADG of HGP-treated steers was higher (P
< 0·05) than that of steers not treated with HGP (0·76
± 0·27 v. 0·60 ±
0·027 kg/day). F : G was reduced (P <
0·01) by HGP treatment. F : G of both HGP-treated steers and those
steers not treated with HGP was reduced (P <
0·05) by AM treatment.
We conclude that feeding steers with this novel AM compound enables the potent
antimethanogenic properties of BCM to be realised under commercial conditions,
and that prolonged use over 10–12 weeks is associated with an improved
feed conversion efficiency in steers fed on better quality roughage diets.
Background/Aims: There are many controversies regarding side effects on craniofacial and extremity growth due to growth hormone (GH) treatment. Our aim was to estimate GH action on craniofacial development and extremity growth in GH-deficient patients. Methods: Twenty patients with GH deficiency with a chronological age ranging from 4.6 to 24.3 years (bone age from 1.5 to 13 years) were divided in 2 groups: group 1 (n = 6), naive to GH treatment, and group 2 (n = 14), ongoing GH treatment for 2–11 years. GH doses (0.1–0.15 U/kg/day) were adjusted to maintain insulin-like growth factor 1 and insulin-like growth factor binding protein 3 levels within the normal range. Anthropometric measurements, cephalometric analyses and facial photographs to verify profile and harmony were performed annually for at least 3 years. Results: Two patients with a disharmonious profile due to mandibular growth attained harmony, and none of them developed facial disharmony. Increased hand or foot size (>P97) was observed in 2 female patients and in 4 patients (1 female), respectively, both not correlated with GH treatment duration and increased levels of insulin-like growth factor 1. Conclusions: GH treatment with standard doses in GH-deficient patients can improve the facial profile in retrognathic patients and does not lead to facial disharmony although extremity growth, mainly involving the feet, can occur.
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